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Uppermost Hettangian to lowermost Pliensbachian (Lower Jurassic) biostratigraphy and ammonoid fauna of… Pálfy, József 1991

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U P P E R M O S T H E T T A N G I A N T O L O W E R M O S T PLIENSBACHIAN (LOWER JURASSIC) B I O S T R A T I G R A P H Y A N D A M M O N O I D F A U N A OF T H E Q U E E N C H A R L O T T E ISLANDS, BRITISH COLUMBIA by JOZSEF P A L F Y Diploma in Geology, Lorand Eotvos University, Budapest, 1986  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR T H E DEGREE OF MASTER OF SCIENCE  in THE F A C U L T Y OF G R A D U A T E STUDIES D E P A R T M E N T OF GEOLOGICAL SCIENCES  We accept this thesis as conforming to the required standard  T H E UNIVERSITY OF BRITISH COLUMBIA 1991 April (c) Jozsef Palfy, 1991  In presenting this thesis in partial fulfilment of the  requirements for an advanced  degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department  or by his  or  her  representatives.  It  is  understood  that  copying or  publication of this thesis for financial gain shall not be allowed without my written permission.  Department of  feoLpfric  AL-  ScietJcsS  The University of British Columbia Vancouver, Canada Date  DE-6 (2/88)  APn.it-  ya  l  \*°> i  ii ABSTRACT  E x t e n s i v e fossil collections from the upper part of the Sandilands and the lowermost Ghost Creek F o r m a t i o n s allowed a detailed taxonomic study of the latest H e t t a n g i a n to earliest P h e n s b a c h i a n a m m o n o i d fauna of the Queen C h a r l o t t e Islands. 61 taxa, allocated to 27 genera, are described. Sunrisites Plesechioceras  yakounense,  Tetraspidoceras  pacificum  and  Tetraspidoceras  recognitum  senihlevis,  are introduced  as  sections, serves as a basis  to  new species. T h e vertical d i s t r i b u t i o n of ammonites, distinguish six successive  assemblage  V a r i a n s Zone, Harbledownense established  earlier, the  resolution  correlation  zones: the  Zone, and  documented Canadensis  i n measured  Zone, " C o r o m c e r a s "  R e c o g n i t u m Zone. O f these only the  Zone, A r n o u l d i Canadensis  Zone  remaining five are defined here for the first time. T h i s zonation permits of  the  sections.  The  total  thickness  of  uppermost  Hettangian  to  Zone, was high-  lowermost  P l i e n s b a c h i a n s t r a t a i n sections on K u n g a Island is estimated at 385 m . A comparison of selected zones i n different sections shows a subtle thickness increase to the south. T h e contact of the Sandilands F o r m a t i o n and the o v e r l y i n g G h o s t Creek F o r m a t i o n is diachronous, younging gradually to the south. T h e faunal succession i n the Queen C h a r l o t t e Islands agrees well w i t h that of the Taseko Lakes area and N e v a d a , p r o m i s i n g regional a p p l i c a b i l i t y of the proposed zones. Intercontinental correlation w i t h the northwest E u r o p e a n standard zonation is possible at diffrent levels. T h e H e t t a n g i a n / S i n e m u r i a n b o u n d a r y is contained  within  the  Canadensis  columbiae  a n d Metophioceras  Zone. It  is best  approximated  b y the  first  appearance of  Badouxia  spp. T h e position of the R e c o g n i t u m Zone at the S i n e m u r i a n / P l i e n s b a c h i a n  b o u n d a r y remains problematic; most evidence on h a n d points to its P l i e n s b a c h i a n affinities. T h e ammonite fauna consists of t a x a w i t h pandemic, T e t h y a n , A t h a b a s c a n , East Pacific, and Pacific d i s t r i b u t i o n . P r o v i n c i a l i s m was not prominent but existed d u r i n g the S i n e m u r i a n time. T h e high p r o p o r t i o n of T e t h y a n  forms is in accord w i t h the  theory suggesting  a more southerly o r i g i n a l paleolatitude  for  W r a n g e l l i a . T h e d i s t r i b u t i o n of T e t h y a n forms can be explained b y the early opening of the H i s p a n i c C o r r i d o r , proven to be i n existence by the P l i e n s b a c h i a n . A l t e r n a t i v e l y , the pantropic d i s t r i b u t i o n model cannot be ruled out, although the faunal record from the eastern T e t h y s is inadequate to prove it. T h e  strong representation  of A t h a b a s c a n and East Pacific elements renders long-distance l o n g i t u d i n a l tectonic  dislocation of W r a n g e l l i a unlikely. T h e paleoecology and t a p h o n o m y of ammonites, associated macrofauna, and trace fossils is used for paleoenvironmental  reconstruction.  The  general  lack  of  bioturbation,  predominance  of  thin-shelled,  presumably pseudo-planktonic bivalves, and the intact preservation of fish and a crinoid specimen indicate prevailing oxygen deficient b o t t o m conditions. T r a c e fossils provide evidence for periodic improvements of b o t t o m oxygenation. Different modes of ammonite preservation are controlled b y shell morphology as well as the v a r y i n g sedimentation rate and diagenetic regime. T h e latter reflects changes i n redox conditions i n the upper sediment layers.  iv T A B L E OF CONTENTS  ABSTRACT  ii  T A B L E OF CONTENTS  iv  LIST OF TABLES  vii  LIST OF FIGURES  viii  LIST OF PLATES  x  ACKNOWLEDGEMENT CHAPTER 1  xii  INTRODUCTION  1  1.1  LOCATION AND ACCESS OF T H E STUDY A R E A  1  1.2  PURPOSE OF STUDY  1  1.3  PREVIOUS WORK  3  1.4  METHODS  6  GENERAL GEOLOGY  7  2.1  GEOLOGICAL SETTING OF T H E QUEEN C H A R L O T T E ISLANDS  7  2.2  STRATIGRAPHY  9  CHAPTER 2  2.2.1  SYNOPSIS OF UPPER TRIASSIC T O LOWER JURASSIC  STRATIGRAPHY  CHAPTER 3  9  2.2.2  SANDILANDS FORMATION  10  2.2.3  GHOST CREEK FORMATION  12  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  13  INTRODUCTION  13  BIOSTRATIGRAPHY OF T H E MEASURED SECTIONS  19  PALEOBIOGEOGRAPHY  47  4.1  INTRODUCTION  47  4.2  EARLIER NORTH AMERICAN SYNTHESES  47  4.3  ASSESSMENT OF T H E QUEEN C H A R L O T T E ISLANDS FAUNA  48  4.4  MODELS EXPLAINING T E T H Y A N FAUNAS IN T H E CORDILLERA  53  . 3.1 3.3 CHAPTER 4  V  CHAPTER 5  PALEOECOLOGY AND TAPHONOMY  55  5.1  AMMONITE PALEOECOLOGY  55  5.2  THE PRESERVATION OF AMMONITES  56  5.2.1  56  5.3  CASE HISTORIES  PALEOECOLOGY OF THE ASSOCIATED MACROFAUNA  59  5.3.1  BIVALVES  59  5.3.2  VERTEBRATES  60  5.3.3  STALKED CRINOID  60  5.4  TRACE FOSSILS  61  5.5  RESULTS  62  SYSTEMATIC PALEONTOLOGY  63  6.1  INTRODUCTION  63  6.2  SYSTEMATIC DESCRIPTIONS  65  CHAPTER 6  PhyUoceras  65  Juraphylhtes  66  Lyioceras  73  Adnethiceras  75  Tragolytoceras  77  Audaxlytoce'ras  79  Eciocentntes  81  Eolytoceras  82  Angulaticeras  86  Sulcifentes  89  Sunnsites  95  Badouxia  98  Vermiceras  108  Metophioceras  114  Coroniceras  120  vi  CHAPTER 7  Amioceras  122  Asteroceras  136  Hypasteroceras  142  Epophioceras  145  Plesechioceras  148  Paltechioceras  156  Oxynoticeras  163  Gleviceras  165  Radstockic eras  167  Crucilobiceras  170  Tetraspidoceras  172  Posidonotis  181  CONCLUSIONS  184  REFERENCES  186  APPENDIX  202  PLATES  209  vii LIST O F T A B L E S  Table 4-1  T e m p o r a l p a t t e r n of genus level p r o v i n c i a l i s m  52  Table 4-2  T e m p o r a l p a t t e r n of species level p r o v i n c i a l i s m  52  viii LIST O F F I G U R E S  F i g u r e 1-1  Index map of the measured stratigraphic sections and fossil localities  2  F i g u r e 2-1  Tectonostratigraphic terranes of the C a n a d i a n C o r d i l l e r a  8  F i g u r e 2-2  U p p e r Triassic-Lower Jurassic l i t h o s t r a t i g r a p h y of the Queen C h a r l o t t e Islands  9  F i g u r e 3-1  Zonation and relative stratigraphic ranges of the ammonite t a x a  15  F i g u r e 3-2  Sketch map of K e n n e c o t t P o i n t showing the location of the measured sections  20  F i g u r e 3-3  Legend for the lithologic columns on F i g . 3-4 to F i g . 3-13  21  F i g u r e 3-4  B i o s t r a t i g r a p h y of Section D at K e n n e c o t t P o i n t  22  F i g u r e 3-5  B i o s t r a t i g r a p h y of Section F at K e n n e c o t t P o i n t  23  F i g u r e 3-6  B i o s t r a t i g r a p h y of Section G at K e n n e c o t t P o i n t . . .  24  F i g u r e 3-7  B i o s t r a t i g r a p h y of Section B at K e n n e c o t t P o i n t  25  F i g u r e 3-8  B i o s t r a t i g r a p h y of Section H at Y a k o u n R i v e r , central G r a h a m Island  26  F i g u r e 3-9  B i o s t r a t i g r a p h y of Section I at Y a k o u n R i v e r , central G r a h a m Island  28  F i g u r e 3-10  B i o s t r a t i g r a p h y of Section L at G h o s t M a m R o a d c u t , central G r a h a m Island  29  F i g u r e 3-11  B i o s t r a t i g r a p h y of Section M on M a u d e Island  31  F i g u r e 3-12  B i o s t r a t i g r a p h y of Section S on K u n g a Island  33  F i g u r e 3-13  B i o s t r a t i g r a p h y of Section T on K u n g a Island  34  F i g u r e 3-14  Biostratigraphic correlation of the measured sections  35  F i g u r e 3-15  L a t e r a l thickness changes of selected zones  36  F i g u r e 3-16  D i a c h r o n i s m at the contact of the Sandilands and G h o s t Creek F o r m a t i o n s  38  F i g u r e 3-17  A p p r o x i m a t e correlation of the proposed ammonite assemblage  zones w i t h the  E u r o p e a n and A l p i n e zonations.  northwest 39  F i g u r e 4-1  . H i s t o g r a m of the number of genera w i t h different d i s t r i b u t i o n p a t t e r n  49  F i g u r e 4-2  H i s t o g r a m of the number of species w i t h different d i s t r i b u t i o n p a t t e r n  50  F i g u r e 4-3  E x a m p l e s of species w i t h different paleobiogeographic d i s t r i b u t i o n  51  F i g u r e 6-1  Septal suture of Juraphylhtes  71  F i g u r e 6-2  Septal suture of Lytoceras  sp  aff. nardn  75  ix  Figure 6-3  Cross section of the holotype of Sunrisites  Figure 6-4  Scatter d i a g r a m of U D vs. D M A X of Badouxia  canadensis  a n d Badouxia  columbiae  100  Figure 6-5  Scatter d i a g r a m of P R H W vs. U D of Badouxia  canadensis  a n d Badouxia  columbiae  101  Figure 6-6  R i b frequency curves of Vermiceras  Figure 6-7  R i b frequency d i a g r a m of Vermiceras  Figure 6-8  R i b frequency curves of Metophioceras  cf. rursicostatum  117  Figure 6-9  R i b frequency curves of Metophioceras  aff. rotarium  119  Figure 6-10  R i b frequency curves of Arnioceras  arnouldi  124  Figure 6-11  R i b frequency curves of Arnioceras  speciosum  131  Figure 6-12  R i b frequency curves of Plesechioceras  yakounense  Figure 6-13  R i b frequency curves of Plesechioceras  ? harbledownense  Figure 6-14  R i b frequency curves of Paltechioceras  cf. romanicum,  Figure 6-15  R i b frequency curves of Paltechioceras  aff. boehmi  Figure 6-16  T u b e r c l e frequency cuves of Tetraspidoceras  Figure 6-17  P r i m a r y r i b frequency of Tetraspidoceras  senililevis  n . sp  96  ex gr. coregonense  112  sp  114  n . sp  pacificum recognitum  151 a n d P. ? aklavikense  P. cf. rothpletzi  and P. sp  155 158 161  n . sp n. sp  175 178  x LIST O F P L A T E S  Plate 1  Juraphyllites  cf. transylvaniens  hmatus, Juraphyllites PLATE 2  Ectocentrites  Eolytoceras  cf. occidentals,  PLATE 4  Badouxia  oregonensis,  PLATE 5  Badouxia  canadensis,  ^ lerTTwceras Vermiceras  PLATE 7  cf. trapezoidalis,  Sulciferites  Badouxia  ? guexi ?, Adnethiceras  Angulaticeras  marmoreus,  columbiae, columbiae,  ex gr. coregonense,  Sunrisites  senililevis,  215 ? sp  217  sp  219  Metophioceras  aff.  rotanum, 221  Arnioceras  miserabile,  Arnioceras  cf.  densicosta,  spp., A r m o c e r a s sp., A r i e t i t i n a e gen. et sp. indet  Arnioceras  cf. speciosum,  P L A T E 10  Arnioceras  ex  Arnioceras  gr.  ceratitoides,  aff. margarita,  Plesechioceras  ? harbledownense,  P L A T E 12  Plesechioceras  yakounense,  P L A T E 13  Paltechioceras  cf.  Crucilobiceras  ? sp.,  aff.  saltriense  Plesechioceras  arnouldi  Gleviceras  cf. rothpletzi,  Oxynoticeras  Oxynoticeratidae  gen.  cannatum,  Asteroceras  229  cf.  subguibalianum,  cf. aklavikense.... Radstockiceras  sp  Posidonotis  indet.,  231  Tetraspidoceras  P L A T E 16  Phricodoceras  ex  233 gr. 235  semiplicata,  Tetraspidoceras  sp.,  Tetraspidoceras Tetraspidoceras  recognitum P L A T E 15  vanans,  ? h arble down ens e ?  Paltechioceras  sp.  cf.  ?  cf. simpsoni, et  225 227  Paltechioc eras aff. boehmi, Plesechioceras?  romanicum,  Paltechioceras  223  Hyp aster ocer as ? sp  Epophioceras  Asteroceras  P L A T E 11  242  ? sp.,  ? sp  PLATE 9  pacificum,  adnethicum,  Sulciferites  Badouxia  Vermiceras  cf. supraspiratum,  ex gr. mendax, Arnioceras  P L A T E 14  cf.  cf. ventneosum  aff. occidentahs,  A r n i o c e r a s cf. oppeli, Arnioceras  numismale,  spezianum,  Angulaticeras  Badouxia  Vermiceras  rursicostatum,  arnouldi,  cf. 211  PLATE 8  Asteroceras  sp., Juraphyllites  sp  ? sp., Eolytoceras  Badouxia  cf.  Metophioceras  spp., Lytoceras  , Phylloceras  213  sp., Coroniceras  Metophioceras  aff. nardii  aff. audax  tasekoi, Sulciferites  Badouxia  PLATE 6  Lytoceras  ? sp., Tragolytoceras  Audaxlytoceras PLATE 3  sp.,  , Juraphyllites  237 recognitum,  Posidonotis  semiplicata,  sp., F i s h remains, Miltoceras  Crucilobiceras  sp., Gemmellaroceras  ? sp sp., Alsatites  239 cf.  proaries  xi P L A T E 17  Camptonectes  (Camptochlamys)  sp., Otapvna sp. A , P t e r i a c e a gen. et sp. indet. 1, P t e r i a c e a  gen. et sp. indet. 2, Pseudomytiloides c e n t r u m , Isocrinida gen. et sp. indet  sp., Limea  ? sp., Oxytoma  sp., Ichthyosaur vertebral 243  xii ACKNOWLEDGEMENT  T h i s thesis was produced under the guidance and supervision of P . L . S m i t h . I wish to express m y thanks for his continuous support, w h i c h often extended b e y o n d the limits of this project, his advice on research problems, and his patience as I adapted to a very different environment. M o s t of the funding for this study was p r o v i d e d through an N S E R C grant to S m i t h . H . W . T i p p e r (Geological S u r v e y of Canada) i n t r o d u c e d me to the rewarding a n d demanding field work i n the Queen C h a r l o t t e Islands and shared his wealth of knowledge on Jurassic biostratigraphy. He provided w o r k i n g space and access to his lab facilities i n the G S C . He is also t h a n k e d for arranging the loan of type material from the G S C collections and for m a k i n g his research material from the Taseko Lakes area available for comparative studies. I a m grateful for the use of S m i t h ' s and T i p p e r ' s research l i b r a r y w h i c h proved to be an invaluable resource. T h e i r detailed and thoughtfu comments on earlier drafts of this thesis resulted i n major improvements of the text. W . C . Barnes ( U B C ) and G . E . Rouse ( U B C ) acted as members of m y supervisory committee and I benefited from their guidance and valuable comments on the thesis m a n u s c r i p t . T h e research was p a r t l y funded by the F r o n t i e r Geoscience P r o g r a m of the G S C and I wish to express m y thanks to this organization for the logistical support i n the summers of 1989 and 1990. T h a n k s are especially due to J . W . Haggart ( G S C ) for m a k i n g m y whole family feel at home i n the Queen C h a r l o t t e Islands. M . N e y l a n provided assistance i n the field. E n l i g h t e n i n g discussions w i t h D . G . T a y l o r ( P o r t l a n d ) a n d the o p p o r t u n i t y of s t u d y i n g his p a r t l y u n p u b l i s h e d material from N e v a d a and Oregon c o n t r i b u t e d to m y u n d e r s t a n d i n g of some systematic and stratigraphic problems. G . Bloos ( S t u t t g a r t ) and S. E . D a m b o r e n e a ( L a P l a t a ) helped interpret taxonomic problems related to the arietitids and bivalves, respectively. Fellow graduate students p a r t i c i p a t e d i n the formation of this s t u d y i n m a n y ways. G . Jakobs helped throughout this project, i n the field as well as i n the lab and b y numerous discussions. T h e c o m p a n y of C . G a m b a , J . Indrelid, J . H e s t h a m m e r , P . Lewis, and S. T a i t e was most enjoyable i n the field, while discussions about the geology of the Queen Charlottes enhanced m y t h i n k i n g on various topics. T a i t e is also thanked for the time and energy she spent i n i n t r o d u c i n g me to the geology of the T a s u S o u n d area, and for m a k i n g her collections from Section R available. B . L i a n g gave advice on c o m p u t i n g problems. I wish to express m y thanks to K . G o r d a n i e r - S m i t h for the caring and professional photography related to this project. D u r i n g m y stay i n C a n a d a I enjoyed the support a n d encouragement of m y collegues i n the Departments of Paleontology of the H u n g a r i a n N a t u r a l H i s t o r y M u s e u m a n d the E o t v o s L o r a n d U n i v e r s i t y , Budapest. M y studies at U B C were an endeavor for the whole family. O u r parents gave a reassuring link to home while tolerating our long absence. I owe m u c h to m y wife M a r i a , who shared only little of the pleasures but most of the hardship related to m y work. W i t h o u t her whole-hearted support the tightrope performance of researching, s t u d y i n g and parenting simultaneously w o u l d not have been possible.  INTRODUCTION  1  CHAPTER 1  1.1  INTRODUCTION  LOCATION A N D ACCESS OF T H E STUDY A R E A  T h e Q u e e n C h a r l o t t e Islands lie o n the western edge of the continental m a r g i n off central B r i t i s h C o l u m b i a . T h e conspicuously wedge-shaped archipelago consists of more t h a n 150 islands of w h i c h the t w o major ones are Graham Island in the north and M o r e s b y Island in the south. A helicopter was used to provide transportation to K e n n e c o t t P o i n t i n northwest G r a h a m Island. Sections i n central G r a h a m Island are easily accessible from Queen C h a r l o t t e C i t y on a network o f logging roads. Shoreline sections of M a u d e Island a n d Sandilands Island were reached b y inflatable boat. Localities i n the T a s u S o u n d area are accessible b y four-wheel drive vehicle on logging roads from Sewell Inlet logging camp. A helicopter or boat can be used to get to K u n g a Island, where an inflatable boat is helpful to move from one section to the other." For  easy  reference  stratigraphic  Fossiliferous levels (collection sites)  sections  are coded  w i t h c a p i t a l letters from n o r t h  w i t h i n each section are numbered  to south.  i n ascending stratigraphic  order.  L o c a l i t y i n f o r m a t i o n is listed i n the A p p e n d i x . T h e location of the measured sections where fossil collections were obtained is s h o w n o n F i g . 1-1.  1.2  PURPOSE OF STUDY  T h i s s t u d y is a c o n t r i b u t i o n to the F r o n t i e r Geoscience P r o g r a m i n the Q u e e n C h a r l o t t e Islands. T h e mandate of the F r o n t i e r Geoscience P r o g r a m is to comprehensively investigate the onshore geology to help future offshore h y d r o c a r b o n exploration. T h e U p p e r N o r i a n to Lower P l i e n s b a c h i a n Sandilands a n d G h o s t Creek F o r m a t i o n s are proven potential source rocks; therefore  biostratigraphic studies are of v i t a l  importance. T h e r i c h latest H e t t a n g i a n to earliest Pliensbachian ammonite fauna of the upper part of the Sandilands a n d lower part of the G h o s t Creek F o r m a t i o n s , well suited for precise dating, was k n o w n  INTRODUCTION  0  Figure 1-1  5  10  20  30  40  50  Index map of the measured stratigraphic sections and fossil localities.  3  INTRODUCTION  a l t h o u g h no detailed study has been undertaken earlier. A l s o , this s t u d y was i n i t i a t e d as part of an effort to erect a regional ammonite zonation for the Lower Jurassic of western N o r t h A m e r i c a . T h e Queen C h a r l o t t e Islands yield one of the most diverse and abundant assemblage of this age. T h e m a i n aims of this thesis can be s u m m a r i z e d as follows: 1.  To  provide  a  complete  taxonomic  treatment  of  the  latest  Hettangian  to  earliest  P l i e n s b a c h i a n ammonite fauna collected from the Queen C h a r l o t t e Islands.  2.  To delimit in measured sections the stratigraphic ranges of the taxa described.  3.  T o establish a local ammonite zonation valid for the Queen C h a r l o t t e Islands w i t h possible  extension of its use to other areas i n western N o r t h A m e r i c a . 4.  T o use the above zonal scheme for correlation w i t h other areas i n western N o r t h A m e r i c a  a n d to discuss the possibilities of global correlation. 5.  T o analyze the paleobiogeographic affinities of the Queen C h a r l o t t e fauna to contribute d a t a  about the h i s t o r y of W r a n g e l l i a . 6. other  T o use the paleoecological conclusions derived from ammonite, trace fossil, bivalve, and  macrofossil assemblages  to help interpret  the depositional environment of the upper  part of the  Sandilands Formation. 7.  T o apply h i g h resolution biochronology to the problems of basin e v o l u t i o n such as  the  lateral thickness trends w i t h i n the studied part of the Sandilands F o r m a t i o n and the t i m i n g of t r a n s i t i o n of the  Sandilands  and  Ghost  Creek F o r m a t i o n s , and  to review some  aspects of the  sedimentology  and  depositional history of the Sandilands F o r m a t i o n .  1.3  PREVIOUS W O R K  Geological investigation of the Queen C h a r l o t t e Islands dates back to the 1870's and paleontological studies have formed a crucial part since the beginning. Comprehensive summaries of Jurassic stratigraphy  INTRODUCTION  4  were given by McLBARN (1949) and more recently by CAMERON and TIPPER (1985). Instead of largely repeating these, a brief account is given w i t h special reference to the Sandilands F o r m a t i o n . In 1872 J . R i c h a r d s o n was the first geologist to visit the Queen C h a r l o t t e Islands but his report  (RICHARDSON, Lower Jurassic  1873) was p r i m a r i l y concerned w i t h the "coal-bearing s t r a t a " and d i d not deal w i t h what is according to our m o d e r n u n d e r s t a n d i n g .  BILLINGS  (1873) examined R i c h a r d s o n ' s  fossil  collections and, based on ammonites, concluded that Jurassic as well as Cretaceous rocks were present. G . M. Dawson's fundamental work is the first comprehensive treatment of the geology of the islands. His opus  (DAWSON,  1880) is j u s t l y amongst the classic pioneer works on C a n a d i a n geology. He recognized  the succession of four u n n a m e d units: a thick pile of volcanic rocks overlain by grey limestones, flaggy, black, Monotis-beanng  beds and flaggy, black argillites. He visited several localities where the black argillite (1. e.  the Sandilands F o r m a t i o n in m o d e r n terms) cropped out, i n c l u d i n g Carpenter southern M o r e s b y Island  (SUTHERLAND BROWN  1968, p. 51, 55), K u n g a Island (p. 61), Skedans B a y (p. 62)  and M a u d e Island (p. 63). He considered the whole section as Triassic subcirculans.  B a y and Section Cove i n  based m a i n l y on the age of  Monotis  A major disturbance was envisaged separating the deposition of this sequence and the overlying  package of five units ( E to A ) , the age of w h i c h was thought  to be Cretaceous.  U n i t E (the " L o w e r  Sandstones") is p r o b a b l y equivalent to the M a u d e G r o u p of modern lithostratigraphy. A persistent confusion of Jurassic and Cretaceous fossils stemmed from a failure to recognize two sandstone units of closely similar lithology but of d i s t i n c t l y different age. J . F . W h i t e a v e s carried out m u c h of the early paleontological research on Mesozoic faunas.  He  recognized Jurassic as well as Cretaceous faunas but favoured a Cretaceous age h a v i n g been p u z z l e d by the above mentioned p r o b l e m and confused by i m p r o p e r l y located collections  (WHITEAVES,  1883, 1884). T h e  revision of Dawson's stratigraphic framework started w i t h the recognition of a major unconformity between U n i t s E..and D (i.e. present-day M a u d e and Y a k o u n groups) (CLAPP, 1914). T h e lithologic description of argillites, locally called " r i b b o n rocks" w i t h i n unit E p r o b a b l y refers to what is now k n o w n as the Sandilands Formation argillite.  (CLAPP,  1914, p. 19).  MACKENZIE  (1916) n a m e d the M a u d e F o r m a t i o n and i n c l u d e d the black  INTRODUCTION  5  The next important contribution was made by  F. H . McLearn in several papers devoted to the  Jurassic-Cretaceous rocks and fossils of the islands. In a detailed treatment of the Maude Formation (MCLEARN, 1949) he referred to the argillites as unfossiliferous beds found on the south shore of Maude Island, in Whiteaves Bay, and on Sandilands Island. The oldest assemblage described by him was the Late Pliensbachian Fannmoceras fauna. A . Sutherland Brown's thorough and comprehensive mapping was a major step beyond the earlier reconnaissance  work. His stratigraphic  revision led to  the  introduction of the  Kunga  Formation  (SUTHERLAND BROWN and JEFFREY, I960) and its further subdivision into three informal members, the highest being the "black argillite" member (SUTHERLAND BROWN, 1968). Fossils from this unit identified by H. FREBOLD (SUTHERLAND BROWN, 1968, p. 60-61: Armotites {Melanhippites) harbledownense,  Arniotites  sp., and Arietites s.l.) indicated a Sinemurian age. In fact, this was the first published record of Sinemurian fossils from the Queen Charlotte Islands. The Maude Formation was retained in a restricted sense as compared to MC LEARN's (1949) interpretation. Another major advance in refining the lithostratigraphy was made by CAMERON and TIPPER (1985). The Kunga and Maude formations were elevated to group status and SUTHERLAND BROWN's (1968) members within his Kunga Formation were treated as independent formations: the "black argillite" was formally named the Sandilands Formation. Similarly the Maude Group was subdivided into five formations, the lowermost being the Ghost Creek Formation (discussed to some extent later in the present study). Likewise a major step forward was made by working out a biostratigraphic scheme (for details see Chapter 2)  INTRODUCTION  6  Interest i n the geology of the Q u e e n C h a r l o t t e Islands has been spurred b y the F r o n t i e r Geoscience P r o g r a m of the Geological S u r v e y of C a n a d a aimed at p r o d u c i n g comprehensive, high quality, 1:50 000 scale maps of the islands and a synthesis of their geological e v o l u t i o n . D e t a i l e d studies at K e n n e c o t t P o i n t for the first time furnished faunal evidence for the presence of uppermost Triassic (CARTER et al., 1989) a n d H e t t a n g i a n (TIPPER, 1989) s t r a t a w i t h i n the Sandilands F o r m a t i o n . F o r the S i n e m u r i a n , p r e l i m i n a r y results of the present s t u d y were published b y PALFY et al. (1990).  METHODS  1.4  A n extensive fossil collection o b t a i n e d d u r i n g a full field season i n 1989 a n d an a d d i t i o n a l 3 weeks field work i n 1990 formed the basis of the present study. E x a m i n a t i o n of the preexisting collections of the Geological S u r v e y of C a n a d a added  supplementary  information. Collections were made  stratigraphic sections. T h e majority of these were measured using the tape technique  except  for  K u n g a Island where  the  Jacob's  staff  from  measured  more accurate B r u n t o n compass and (Pogo stick) m e t h o d  was  employed  (COMPTON, 1962). In the first case the true stratigraphic thicknesses were calculated u t i l i z i n g the F o r t r a n program S T R A T  (SMITH, 1976). T h e considerable thickness of the formation (at some sections several  h u n d r e d meters exposed), the relative scarcity of fossils at some horizons, and the l a m i n a t e d lithology renders the ideal case of bed-by-bed collection i m p r a c t i c a l . However, p a r t i c u l a r care was taken to ensure that collections  were  as  closely spaced  as  possible. T h e  mean  stratigraphic  distance  between  superjacent  collections is 2-3 m w i t h a spread between 0.2 a n d 30 m . In the t a x o n o m i c work, the majority of the N o r t h A m e r i c a n S i n e m u r i a n a m m o n o i d type material (that of FREBOLD a n d CRICKMAY) was s t u d i e d for comparison. T o facilitate d a t a entry, qualitative and quantitative descriptions conform w i t h the A M M O N database developed at U B C (SMITH, 1986).  GENERAL GEOLOGY  CHAPTER 2  2.1  GENERAL GEOLOGY  GEOLOGICAL SETTING OF T H E Q U E E N C H A R L O T T E ISLANDS  T h e Queen C h a r l o t t e Islands are located on the western m a r g i n of the C a n a d i a n C o r d i l l e r a f o r m i n g part of the Insular B e l t . T h e western part of the C o r d i l l e r a is viewed as a collage of allochthonous terranes, foreign to the N o r t h A m e r i c a n craton. E a c h terrane is a fault-bounded crustal fragment  with distinctive  stratigraphy (CONEY et al., 1980, MONGER, 1984). T h e Queen C h a r l o t t e Islands share their U p p e r Paleozoic to Lower Jurassic stratigraphic record w i t h south-central A l a s k a , most of V a n c o u v e r Island, a n d d i s p u t e d l y w i t h northeastern Oregon, and are considered part of the displaced terrane W r a n g e l l i a (JONES et al., 1977) ( F i g . 2-1). C o m p e l l i n g paleomagnetic and paleontologic evidence suggests that W r a n g e l l i a was formed far south of its present latitude (HlLLHOUSE, 1977; Y O L E and IRVING, 1980; TAYLOR et al., 1984). G e o p h y s i c a l d a t a for its original longitude and possible trajectories constrained  prior to d o c k i n g to N o r t h A m e r i c a are not  well  (DEBICHE et al., 1987). Different plate tectonic models have been proposed to e x p l a i n the  accretion of W r a n g e l l i a to N o r t h A m e r i c a . T h e amalgamation of W r a n g e l l i a and the A l e x a n d e r terrane m a y have led to the formation of a composite terrane by the Late Jurassic (MONGER et al., 1982) as evidenced b y the overlapping G r a v i n a - N u t z o t i n assemblage i n A l a s k a (BERG et al., 1972). A n alternative  interpretation  suggests that these two terranes were assembled as early as the L a t e Paleozoic (GARDNER et a l . , 1988). T h e accretion of this composite terrane lead to the onset of m a g m a t i c a c t i v i t y i n the Coast P l u t o n i c C o m p l e x (MONGER et al., 1982) i n m i d - E a r l y Cretaceous time (ARMSTRONG, 1988). A l t e r n a t i v e l y , the C o a s t P l u t o n i c C o m p l e x m a y represent the root of a magmatic arc w i t h i n the earlier assembled Insular a n d  Intramontane  composite terranes formed b y an east-dipping s u b d u c t i o n zone (VAN DER HEYDEN, 1989). T h e subsequent fragmentation and n o r t h w a r d translation by right-lateral strike-slip movements is possibly a result of the oblique convergence of F a r a l l o n , K u l a , and N o r t h A m e r i c a n plates (DEBICHE et al., 1987).  GENERAL GEOLOGY  Figure 2-1 Tectonostratigraphic terranes of the Canadian Cordillera (after ARMSTRONG, 1988).  GENERAL GEOLOGY  STRATIGRAPHY  2.2  2.2.1  SYNOPSIS  OF UPPER  TRIASSIC  TO LOWER  JURASSIC  STRATIGRAPHY  Upper Triassic to Lower Jurassic strata of the Queen Charlotte Islands form a coherent sedimentary cycle in a continuous sequence (Fig. 2-2). A brief account is given here to provide the necessary background for the interpretation of Sinemurian rocks. The Karmutsen Formation is a several kilometer thick pile of mostly submarine tholeiitic basalts  CHRONOSTRATIGRAPHY AALENIAN  Ma  187  TOARCIAN  co co < or  ZD  >or <  1111111111111111ITTTTT PHANTOM CREEK FORMATION WHITEAVES FORMATION  193 o  LITHOSTRATIGRAPHY  FANNIN FORMATION  PLIENSBACHIAN GHOST CREEK FORMATION  _ J  198  o_ 3 O CH O LU  a  < zs.  SINEMURIAN Z04  SANDILANDS FORMATION  HETTANGIAN  oo < rr  o <  PERIL FORMATION  NORIAN LU  10  ZD  CH 208  O  a.  225  SADLER LIMESTONE  230  KARMUTSEN FORMATION  CAR N IAN  LADINIAN  Figure 2-2 Upper Triassic-Lower Jurassic lithostratigraphy of the Queen Charlotte Islands (modified from LEWIS et al, in press).  o  zz  ZD  GENERAL  GEOLOGY  forming  basement  the  of  10  the  overlying K u n g a a n d  Maude  Group  sedimentary  rocks.  Geochemical  characteristics suggest a rifting back-arc environment for the K a r m u t s e n basalts (ANDREW and GODWIN, 1989, PLAFKER et al., 1989). T h e K a r n i a n Sadler Limestone represents low-energy s u b t i d a l environment of a carbonate shelf (DESROCHERS and  ORCHARD, i n press).  Deepening of the  shelf is recorded  by  dark  calcareous mudstones of the P e r i l F o r m a t i o n ranging up to Late N o r i a n time. T h e U p p e r N o n a n to Lower P l i e n s b a c h i a n Sandilands a n d overlying G h o s t Creek F o r m a t i o n s , deposited i n a more distal basin,  are  discussed i n detail below. T h e F a n n i n F o r m a t i o n (Lower P l i e n s b a c h i a n to lowermost T o a r c i a n ) is considered a regressive  succession  (CAMERON and TIPPER, 1985). T h e paraconformably  overlying W h i t e a v e s  and  P h a n t o m Creek F o r m a t i o n s p r o b a b l y represent a subsequent, smaller, eustatically controlled sedimentary cycle (CAMERON and TIPPER, 1985).  2.2.2  SANDILANDS  FORMATION  T h e Sandilands F o r m a t i o n was i n t r o d u c e d b y CAMERON and TIPPER (1985) for the black argillite member of SUTHERLAND BROWN (1968) after raising the formerly used K u n g a F o r m a t i o n to group status. T h e Sandilands  F o r m a t i o n ranges in age from the  Late N o r i a n (CARTER et  al., 1989)  to the  Early  P l i e n s b a c h i a n (SMITH et a l , 1990). Detailed lithological description of the Sandilands F o r m a t i o n is given by SUTHERLAND BROWN (1968) and CAMERON and TIPPER (1985). It is t y p i c a l l y composed of mterbedded dark shale and dark grey or blue siltstone.  F i n e to m e d i u m grained, sometimes  graded  sandstone and  tuffaceous  interbeds  are  c o m m o n . T h e rock is generally t h i n l y bedded, i n d i v i d u a l beds seldom exceed 10 c m i n thickness, averaging between 2-5 c m . It is well i n d u r a t e d and fissile along the bedding planes. T u r b i d i t i c origin for part of the formation was proposed by CAMERON and TIPPER (1985). O u r field observations suggest that the entire formation can be interpreted by a distal t u r b i d i t e depositional model. Complete B o u m a sequences are not found. G r a d e d sandstones (division A) are c o m m o n at K e n n e c o t t P o i n t but do not exceed 5 c m i n thickness. Massive or parallel l a m i n a t e d sandstone (division B ) f o r m several  GENERAL  11  GEOLOGY  u n u s u a l l y thick beds (up to 1 m ) on K u n g a Island (Section T ) a n d i n the T a s u S o u n d area (Section R ) . R i p p l e d a n d convolute bedding are most frequent  at K e n n e c o t t P o i n t . V o l u m e t r i c a l l y the formation is  m a i n l y composed of division D-E couplets of the B o u m a sequence. T o g e t h e r w i t h the remarkable u n i f o r m i t y and lack of lateral changes of i n d i v i d u a l beds i n outcrop, this suggests basin p l a i n (MUTTI, 1977) a n d unchannelized lower fan facies (WALKER, 1984). T h e overall dark color of the formation is related to its high organic content due to p r e v a i l i n g anoxic bottom conditions. S u p p o r t i n g paleoecological evidence is presented i n C h a p t e r 5. The anaerobic-dysaerobic regime m a y have been controlled b y basin topography (silled basin m o d e l : DEMAISON a n d MOORE, 1980) a n d / o r h i g h p r i m a r y p r o d u c t i v i t y . T h e h y d r o c a r b o n source rock p o t e n t i a l of the formation is assessed by BUSTIN a n d MACAULEY (1988) a n d VELLUTINI (1988). T h e t o t a l thickness of the formation is difficult  to estimate  due to s t r u c t u r a l complexities. A n  estimate of the uppermost H e t t a n g i a n to lowermost P l i e n s b a c h i a n part is made i n C h a p t e r 3. T h e subtle increase i n thickness to the south is also discussed i n C h a p t e r 3. T h e lateral facies changes over a distance of approximately 120 k m i n N W - S E direction are m i n o r . This  uniformity  northeastern  is possibly greater  i f the closely similar  t i p of V a n c o u v e r Island is considered  Harbledown  Formation  exposed  near  (JELETZKY, 1970). CAMERON a n d TIPPER  the  (1985)  proposed a back-arc basin depositional m o d e l w i t h volcanic arc source l y i n g to the west. L a t e r a l c o n t i n u i t y along the basin axis is i n keeping w i t h this interpretation a n d one w o u l d expect more p r o x i m a l facies to the west. In fact the westernmost  localities ( K e n n e c o t t P o i n t a n d Section R at T a s u Sound) differ from the  others i n h a v i n g more A , B, a n d C divisions o f the B o u m a sequence. Section R also yielded ornate gastropods and coral fragments interpreted as a resedimented shallow water assemblage from a i m t h i c k quartz-rich sandstone bed (S. TAITE, pers.  comm.). A t Kennecott  P o i n t , west  of the measured  sections  massive  sandstone beds possibly represent channel facies ( C . GAMBA, pers. c o m m . ) . T h i c k sandstone beds w i t h i n the Sandilands F o r m a t i o n are also found near Shields B a y ( P . LEWIS, pers. c o m m . ) . T h e more p r o x i m a l facies of a fan system m a y be submerged or cut off b y the Queen C h a r l o t t e F a u l t s y s t e m a n d transported farther to northwest. W i t h regard to a source area, the T a l k e e t n a A r c of the P e n i n s u l a r terrane i n southeast A l a s k a  GENERAL GEOLOGY  12  and the B o n a n z a G r o u p volcanic rocks of V a n c o u v e r Island were suggested as possibilities (CAMERON a n d TIPPER, 1985, LEWIS et al., i n press). T h e observed southward thickening and the shift of S a n d i l a n d s / G h o s t Creek transition together w i t h the westward increasing p r o x i m a l i t y point to a source i n southwest according to present coordinates.  S.S.3  GHOST  CREEK  FORMATION  T h e G h o s t Creek F o r m a t i o n was introduced b y CAMERON a n d TIPPER (1985) for a recessive dark shale unit comformably overlying the Sandilands F o r m a t i o n . T h e contact is gradational a n d i n the studied sections no sharp boundary can be d r a w n between the two formations. T h i s study is concerned o n l y w i t h the lower part o f the G h o s t Creek F o r m a t i o n i n central G r a h a m Island a n d M a u d e Island. T h e age a n d the diachronous nature of the contact is discussed i n C h a p t e r 3. T h e G h o s t Creek F o r m a t i o n ranges from the R e c o g n i t u m Zone (introduced here as probably latest S i n e m u r i a n to earliest P l i e n s b a c h i a n ) to the W h i t e a v e s i Zone ( E a r l y Pliensbachian) i n age (TIPPER et al., 1991). T h e predominant lithology is soft, dark shale. Sandstone a n d tuffaceous interbeds are less frequent t h a n i n the u n d e r l y i n g Sandilands F o r m a t i o n . T h i s indicates decreased volcanic a c t i v i t y i n the source area or alternatively increased distance from the depositional site, resulting i n the preponderance of hemipelagic m u d sedimentation less frequently i n t e r r u p t e d b y turbidites or tuffaceous  interbeds.  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  CHAPTER 3  13  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  INTRODUCTION  3.1  A m m o n i t e s , the most a b u n d a n t macrofossils of the S a n d i l a n d s F o r m a t i o n , are the preferred fossils for dating and correlation of marine Mesozoic rocks. In E u r o p e , where stratigraphic studies and the use of ammonites for correlation date back to the late 1700's, OPPBL a n d QUENSTEDT laid d o w n the foundation of a Jurassic zonal scheme nearly 150 years ago. A relentless effort to refine this framework c u l m i n a t e d i n a classic paper b y DEAN et a l . (1961) formalizing a s t a n d a r d z o n a t i o n for the Lower Jurassic of northwest E u r o p e . T r a d i t i o n a n d superior level of knowledge justify its status as being the p r i m a r y s t a n d a r d for biochronology (CALLOMON, 1984). However, the effect  of a m m o n i t e  p r o v i n c i a l i s m was recognized early  (NEUMAYR, 1883); e.g. WAHNER i n his classical series of monographs (1882-1898) proposed a zonal scheme for the A l p i n e region different f r o m that of northwest E u r o p e due to the significant faunal differences. T h e correlation between the M e d i t e r r a n e a n a n d Northwest E u r o p e a n provinces has not yet been fully resolved and this emphasizes the need for independent regional zonal schemes (CALLOMON, 1984). Reconnaissance work i n W e s t e r n C a n a d a relied o n gross correlation w i t h the northwest (e.g. FREBOLD a n d TIPPER, 1970). M o r e detailed  standard  paleobiogeographic differences,  analysis has, however, demonstrated  i n c l u d i n g endemic Pacific elements,  sequences, a n d different ranges of c o m m o n taxa, warrant  European that  overall closer affinities w i t h T e t h y a n  the erection of a regional  chronostratigraphic  standard useful for regional correlation before proceeding to a global scale. In this context a P l i e n s b a c h i a n zonation for N o r t h A m e r i c a was recently developed b y SMITH et a l . (1988). In  this  study  a local  biostratigraphic  zonation  for the uppermost  Hettangian  to  lowermost  Pliensbachian of the Queen C h a r l o t t e Islands is proposed. T h e ranges of ammonite t a x a are documented i n measured sections. S i x a m m o n i t e zones are established a n d their usefulness for correlation w i t h i n the Queen C h a r l o t t e Islands and s u b d i v i s i o n of the lithologically monotonous Sandilands F o r m a t i o n is demonstrated.  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  14  Geological implications such as thickness trends a n d age relationship w i t h  the overlying Ghost Creek  F o r m a t i o n are also discussed. The succession  fossiliferous in  the  and apparently  Queen  Charlotte  complete  Islands  uppermost  provides  a  Hettangian  basis  to  the  to lowermost erection  of  Pliensbachian an  ammonite  chronostratigraphic zonation for the S i n e m u r i a n of western N o r t h A m e r i c a . V a l i d chronozones should be based o n biozones recognizable over a wide geographic area (CALLOMON, 1984; GUEX, 1987). T h e local zones are evaluated i n this wider perspective by comparison w i t h the record of other N o r t h A m e r i c a n localities a n d possible correlation w i t h the p r i m a r y standard northwest E u r o p e a n scale as well as zonations developed i n other areas of the w o r l d . T h e ongoing project of Lower Jurassic biostratigraphy of the Queen C h a r l o t t e Islands involves a t e a m of biostratigraphers. A n ammonite zonation against  w h i c h zonal schemes of other  such as the one proposed here, can serve as a reference  fossil groups  (e.g. radiolanans, nannofossils, i c h t h y o l i t h s ) can be  calibrated (TIPPER et a l , 1991).  3.2  T H E A M M O N I T E ZONATION FOR T H E Q U E E N C H A R L O T T E ISLANDS  F r o m the d a t a presented i n chapter 3.3 a composite range chart was c o m p i l e d ( F i g 3-1). B a s e d on the v e r t i c a l d i s t r i b u t i o n of a m m o n o i d t a x a a local zonal scheme is proposed for the uppermost H e t t a n g i a n to lowermost P l i e n s b a c h i a n of the Queen C h a r l o t t e Islands. T h e characteristics of the six a m m o n i t e assemblage zones i n ascending order are as follows.  3.2.1  The Canadensis  Zone  T h e Canadensis Zone, proposed by FREBOLD (1967), was the first formal a m m o n i t e zone i n the Lower Jurassic of N o r t h A m e r i c a . In the Queen C h a r l o t t e Islands it is characterized b y a rich assemblage of the very a b u n d a n t Badouxia,  early arietitids and endemic lytoceratids accompanied b y rare schlotheimiids  BIOSTRATIGRAPHY AND  STAGE  HETT.  ?  PLI.  Imlayi  Recognitum  Harbledownense  Varians  Arnouldi  TAXA^X Schtothemia n. sp. Afsatitesct proah»s Badouxia oregonensis Backxixia canadensis Vermiceras cf. supraspiraturn  "Coroniceras"  ZONE  15  SINEMURIAN Canadensis  \  BIOCHRONOLOGY  •  Badouxia cf. occidentals Eolytoceras ? guexi? Verrriceras ex gr. coregonense Eotytoceras tasekoi Anguiaticeras cf. ventrteosum ScJcrferrtes cf. trapezotdals Metophioceras cf. rurstcostadum Sunrisftes senilevts Arietffinae gen. et sp. rtdet  •  Lytoceras spp. Ectocerrtrites ? sp. Metophioceras spp. Badouxia columbiae Metophioceras aff. rotarium Badouxia ?sp. Badouxia aft. c«rfdeinta<s Lytoceras sp. Sutelferites rnarmoreus Sutaferites ? sp. Vermiceras sp. Phytoceras sp. Juraphyftes sp. Juraphyites cf. tarwytvanieus  • • • • •  • •  Arnioceras sp. Coroniceras ? spp. Arnioceras arnoukf Arnioceras ex gr. mendax Arnioceras cf. speciosum Arnioceras ex gr. ceratitoides Arnioceras mtserabet Audaxtytoceras afl. audax Juraphyftes cf. hiatus Adnethiceras ct. adnethicum Arnioceras cf. densicosta Anguiaticeras spezianum Arnioceras ct. oppei Tragotytoceras 7 sp. Asteroceras afl. margarita Epophtocerao aff. cahnatum Asteroceras cf. varians Asteroceras sattrieme ? Hypasteroceras ? sp. Oxynoticeras cf. simpsoni Plesechioceras yakounense  •  •• • • • —  Plesechioceras ? cf. aktavtkense Tetraspidoceras sp. Gleviceras cf. subguibalanurn Tetraspidoceras pacificum Plesechioceras ? rtarbiedownense Pattechioceras cf. romaricurn Paltechioceras aff. boehmi Pattechioceras cf. rothpietzi Pattechioceras sp. Posidonots serrspfcata  • • •  • •  C^uclobiceras ? sp. Juraphyftes aff. narcf RaoStocWceras ex gr. riumismaie Tetraspidoceras recognitum OxynoticeratkJae gen. et sp. indet Qerrrnelaroceras sp.  • •  Mltoceras sp. PseudoskJroeeras imlayi  Figure 3-1 Zonation and relative stratigraphic ranges of latest Hettangian to earliest Pliensbachian ammonites of the Queen Charlotte Islands.  —  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  16  and phylloceratids. T h e base of the zone is defined by the first appearance of Badouxia  canadensis  w h i c h is  c o m m o n throughout the zone except, perhaps, the topmost part. It is most abundant i n the lower h a l f of the unit. Badouxia  oregonensis  and possibly Vermiceras  cf. supraspiratum  range u p w a r d from the  subjacent  U p p e r Hettangian unit to the basal part of this zone. T h e endemic Eolytoceras  tasekoi and E. ? guexi ? are  confined to the zone. Sporadic occurrences of schlotheimiids (Angulaticeras  cf. ventricosum,  marmoreus,  Sulciferites  gr. coregonense  cf. trapezoidalis,  Sulciferites  Sulciferites  ? sp.) are recorded throughout the zone. Vermiceras  ex  is found t y p i c a l l y i n the lower part. A twofold s u b d i v i s i o n w i t h i n the zone already suggested  b y FREBOLD (1967) and more recently by TAYLOR (1991) is possible, as Badouxia more diversified Metophioceras  spp. are restricted to the upper part. Vermiceras  columbiae  along w i t h  sp. (possibly a new species)  occurs only at the top of the zone. T h e best reference sections of the zone at K e n n e c o t t P o i n t are Section D and F whereas Section G and B help to define its lower and upper boundaries. T h e zone is also recognized i n Section O (Skidegate Inlet) and S ( K u n g a Island).  3.2.2  The "Coroniceras"  Zone  T h e "Coroniceras" Zone is introduced to embrace an i n t e r v a l between the Canadensis and A r n o u l d i Zones represented b y a generally poorly preserved and poorly understood assemblage of Coroniceras the persistent Angulaticeras  Juraphyllites cf. ventricosum,  cf. transylvanicus  together  with  Metophioceras  aff. rotarium,  all ranging up from w i t h i n the Canadensis Zone. Arnioceras  ? spp.,  M. spp., a n d sp. first appears  at the base of the zone. N o complete section of this unit is k n o w n in the islands. Its base is defined i n Section B  at  K e n n e c o t t P o i n t . T h e lowest beds of Section T and parts of Section S at K u n g a Island are also assigned to this zone.  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  3.2.3  The Arnouldi  17  Zone  T h e A r n o u l d i Zone is characterized by a rather diverse assemblage of Arnioceras arnouldi  appears first. It persists i n t o the V a r i a n s Zone together w i t h A. cf. oppeli and A. ex gr.  Arnioceras zone.  species, of w h i c h A.  miserabile,  Juraphyllites  (Audaxlyioceras  A. cf. densicosta,  cf. transylvaniens  A. cf. speciosum, last  aff. audax, Adnethiceras  and A. ex gr. mend ax seem to be confined to this  appears w i t h i n this unit. Several extremely rare cf. adnethicum,  ceratitoides.  Tragolytoceras  lytoceratids  sp.) are also recorded from the  zone. T h e upper part of the zone is documented i n section H . T h e zone is proved in Sections M and N i n Skidegate Inlet and widespread in the T a s u S o u n d area (Sections P , Q , R ) .  It is well developed  but  tectonically d i s r u p t e d i n b o t h Section S and T on K u n g a Island.  3.2.4  The Varians  Zone  T h i s zone is defined by an assemblage of asteroceratids confined to this unit and cooccurring, i n its lower part, w i t h long-ranging species of Arnioceras ceratitoides). varians  T h e first Asteroceras  and A. saltriense  and Hyp asteroceras  (A.  arnouldi,  to appear is A. aff. margarita,  A. cf. speciosum,  A. cf. oppeli, A. ex gr.  accompanied at higher levels by A. cf.  ?. O t h e r significant elements confined to this unit are Epophioceras  aff.  cannaium  ? sp.  A t Y a k o u n R i v e r the upper part of the zone is exposed i n Section I whereas section H contains only a faulted slice of its lower part. T h e zone is present i n M a u d e Island (Section M ) and well represented i n a tectonically complex section i n K u n g a Island (Section S and T ) .  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  3.2.5  The Harbledownense  18  Zone  T h e base of this zone, as understood here, is m a r k e d b y the first appearance of oxynoticeratids and echioceratids. T h e first family is represented b y Oxynoticeras  cf. sirrvpsom and Gleviceras  restricted to the lower part of the zone. T h i s i n t e r v a l is d o m i n a t e d by the Plesechioceras  (P.  yakounense,  P.  ?  harbledownense,  P.  ?  cf.  aklavikense)  cf.  subguibalianum,  closely related species of of  which  only  P.  ?  harbledownense ranges to the upper part of the u n i t . F u r t h e r investigation may warrant s u b z o n a l subdivision based on various species of Paltechioceras  (P.  aff. boehmi,  P. cf. romamcum,  cooccurring i n the upper part of the zone. T h e occurrence of Tetraspidoceras  P. cf.. rothpletzi,  pacificum  and  P. sp.)  Tetraspidoceras  ? sp. near the base of the zone is notable. Section H at Y a k o u n R i v e r provides a reference section for the zone which is also present i n Sections I, K , M , S, and T .  3.2.6  The Recognitum  Zone  Characteristic species include eoderoceratids, Juraphyllites semiplicata.  aff. nardii  and the p e c t i n i d  Posidonotis  T h i s bivalve c o m m o n l y occurs crowded on b e d d i n g planes, and ranges t h r o u g h o u t most of the  zone together w i t h Crucilobiceras  ? sp. Juraphyllites  zone and ranges to the Imlayi Zone. Tetraspidoceras  aff. nardii is a b u n d a n t in some beds i n the upper part of recognitum  seems to be confined to the topmost part of  the u n i t where it can be accompanied by rare oxynoticeratids (Radstockiceras  ex gr. numismale  and  O x i n o t i c e r a t i d a e gen. et sp. indet.). N o continuously fossiliferous transition between the Harbledownense and R e c o g n i t u m Zones has been seen; i n a l l cases there is a significant barren i n t e r v a l between the last Paltechioceras Posidonotis  or Crucilobiceras.  a n d the first  Section H at Y a k o u n R i v e r is designated as a reference section. T h e upper  part of the zone is k n o w n from M a u d e Island (Section M ) and the t r a n s i t i o n to the I m l a y i Zone is also documented i n Section T ( K u n g a Island).  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  19  3.3  B I O S T R A T I G R A P H Y OF T H E M E A S U R E D SECTIONS  3.3.1  NORTHWEST  GRAHAM  ISLAND  K E N N E C O T T POINT (SECTIONS A-G) A t Kennecott P o i n t the U p p e r Triassic, H e t t a n g i a n , and Lower Sinemurian parts of the  Sandilands  F o r m a t i o n are well exposed resting conformably on the P e r i l F o r m a t i o n , and capped by volcanics of the unconformably overlying T e r t i a r y Masset F o r m a t i o n (HlCKSON, 1989). T h e Canadensis Zone crops out i n a large i n t e r t i d a l platform  where several s m a l l n o r m a l and  sinistral transcurrent faults  have resulted  in  repetitions. T h e location of the measured sections are shown on F i g . 3-2. A conspicous 40 c m thick carbonate cemented sandstone bed in the lower part of the Canadensis Zone is used as a lithologic marker to decipher s t r u c t u r a l complications p e r m i t t i n g correlation between sections D , F , and G . T h e Canadensis  Zone is the  most fossiliferous unit; it is nearly 35 m thick ( F i g . 3-3 to 3-6). T h e lower contact of the Canadensis Zone is best exposed in Section G , although the first appearance of Badouxia canadensis is not as far below  the  marker bed here as i n Section D a n d F . T h e base of Section D is at the low tide line. Section F starts at a boulder field near a fault. T h e "Coroniceras" Zone contains a poor fauna. T h e highest beds in Section B yielded Arnioceras sp. along w i t h Coroniceras ? spp. ( F i g . 3-7). Section A at the southernmost tip of the Sandilands exposures is a tectonically repeated slice of the u p p e r part of the Canadensis Zone.  CENTRAL  3.3.2  GRAHAM  ISLAND  Y A K O U N R I V E R ( S E C T I O N S H A N D I) Section H on the west b a n k of Y a k o u n - R i v e r constitutes a long a n d relatively little sequence  disturbed  of the Sandilands a n d G h o s t Creek formations w i t h A r n o u l d i Zone through Lower P l i e n s b a c h i a n  faunas ( F i g . 3-8)'. T h e A r n o u l d i Zone and the V a r i a n s Zone are in fault contact and m u c h of the latter is  Figure 3-2 Sketch map of Kennecott Point showing the location of the measured sections (Sections B-G). Section A is approximately 100 m south of Section B.  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  • •  V V  V  V V  V  ss V  •  «  • •  * « •  • • •  « • •  « « •  < • I  SdndsUone  Siltstone  Shale  •  •  V  Graded  Volcanic rocks  sandstone  (dyke or sill)  A  A  A  A  A  Interbedded sandstone, siltstone and shale  A  Tuff,  Limestone  tuffaceous clay (not to scale)  a  CJ o  a  a  Concretionary bed  Figure 3-3  ••^••••i  mm  Covered  Fault  Fault  interval  (proved)  (assumed)  Legend for the lithologic columns on F i g . 3-4 to F i g . 3-13.  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  22  a. a. .5 -a LU  Z  C  U  c  u  3  n  c •"  -  ^  ~" fl  3 5 »- ^  o  fl .r s  u •-  £ S -  x  ZONE  —  3  3  o "»  •J  w u  .2 5 fl 2>• bo on ,>•  <  Ui  t.  c  C  q  ^ C  K ^  T  »SJ  -  S  — f*  —  c  c = A —  w w  IC  20  \-  IS • IH  — .10  Q Z <  • I?  •16  • tr  D Z  <  • if  10  li •U  ;l •a  •I •5 • <t  Figure 3-4  Biostratigraphy of Section D at Kennecott Point.  Canadensis  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  LH LU  <  z  c  u  2 s -=  d  « o  •a c  ? "2 —  a:  c  3.  A * — ™  u  5 H E  ' P O O S  C -c -o x  U fl fl fl  >  30  a  a  £  "  £  c 3  ; ^ "J  >  3  (SI  3  (/)  UJ UJ  fl 3 w  12  fl  c u c oo u u « c 3  3  2 £ "5. 0  c  X  yi  11 JI  Illl  •3 .Z  V  rie  I-  T"  w :2  Ids  Z  4J  tun  .a "  23  S  <<  3 -3  Q J) fl  ZONE  il lr  c 0 Xi  fl 2  CS  20  '13  id • I?  4- >6 - 15"  20  AA A.  .(3  Q  Q Z <  Canadensis  .10  •3 10 —  6  •3  -L  1— 1  Figure 3-5  .1  Biostratigraphy of Section F at Kennecott Point.  —7 _ —^ _  Sunrisiles 1 sp. Vermiceras sp. indet. Schlotheimia n. sp. Alsatites cf. proaries Badouxia sp. indet. Badouxia canadensis Eolytoceras cf. tasekoi  LEVEL  LITHOLOGY  THICKNESS  FORMATION  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  ZONE  —  Canadensis  _ 13 -  11  SANDILANDS  - tl  10  - * " — " — • '  •  - 10 -  3  - 6 - 7  •  Upper Hettangian  -6  - 5  -1 - 3  -L  - 1  Figure 3-6  •  Biostratigraphy of Section G at Kennecott Point.  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  25  « .5 Z  c  cn  LU  Z  C  c  cn  U  o  I 1-  I—  c  .  x - c .£ a. a =  u " o  ZONE  E 2 5 ij -2 £ « « •= 5 > 5 J < <  HZ  T 6  "Coroniceras" T  10  Q Z  6  ...I'  < _i Q Z <  cn  Figure 3-7  3  Canadensis  Biostratigraphy of Section B at Kennecott Point.  26  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  A r n i o c e r a s sp. indet. Arnioceras miserabile A r n i o c e r a s ex gr. m e n d a x A r n i o c e r a s ex gr. c e r a t i t o i d e s Arnioceras arnouldi T r a g o l y t o c e r a s i sp. A s t e r o c e r a s cf. varians A s t e r o c e r a s sp. indet. E p o p h i o c e r a s aff. c a r i n a t u m  I  O x y n o t i c e r a s cf. s i m p s o n i  P  O x y n o t i c e r a t i d a e g e n . et s p . indet  W  Plesechioceras yakounense G l e v i c e r a s cf. s u b g u i b a l i a n u m T e t r a s p i d o c e r a s ? sp. Plesechioceras ? harbledownense Plesechioceras ? aklavikense P a l t e c h i o c e r a s ? sp. indetP a l t e c h i o c e r a s cf. r o m a n i c u m P a l t e c h i o c e r a s aff. b o e h m i P a l t e c h i o c e r a s cf. r o l h p l e t z i P a l t e c h i o c e r a s sp. Posidonotis semiplicata C r u c i l o b i c e r a s ? sp. J u r a p h y l l i t e s aff. n a r d i i Tetraspidoceras recognitum  Oxynoticeratidae gen. et sp. Indet M i l t o c e r a s ? sp. G e m m e i l a r o c e r a s ? sp.  I <  53  cr it  N  n O  at -< re  o  Z m  3  Figure 3-8  Biostratigraphy of Section H at Yakoun River, central Graham Island.  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  27  tectonically missing. T h e Harbledownense, R e c o g n i t u m , and I m l a y i Zones are well documented w i t h m i n i m a l s t r u c t u r a l c o m p l i c a t i o n . T h e lithostratigraphic t r a n s i t i o n f r o m the Sandilands to G h o s t Creek F o r m a t i o n occurs i n the R e c o g n i t u m Zone. Section I contains exposures on both banks c o r r e c t a b l e across the Y a k o u n R i v e r further  upstream  from Section H , separated by a substantial covered i n t e r v a l at the elbow of river. Beds of the V a r i a n s Zone are conformably overlain b y the lower part of the  Harbledownense  R e c o g n i t u m Zone indicated by Posidonotis  ( F i g . 3-9).  semiplicata  Zone w h i c h is faulted  against  the  " F L A G S T O N E " Q U A R R Y (SECTION K) T h e U p p e r S i n e m u r i a n section of this quarry was the subject of a s t u d y by M c F A R L A N E (1988). T h e stratigraphic section together w i t h a range chart is refigured i n PALFY et al. (1990). N o new collections were obtained but the reevaluation of the material on h a n d confirmed that the section represents the V a r i a n s and Harbledownense Zones. T h e succession is closely comparable w i t h that of Section H .  G H O S T M A I N R O A D C U T ( S E C T I O N L) A short section exposing the R e c o g n i t u m / I m l a y i Zone t r a n s i t i o n w i t h i n the G h o s t Creek F o r m a t i o n was freshly excavated in a roadcut yielding a s m a l l but significant fauna ( F i g . 3-10). Fossiliferous levels of the two zones are separated b y a less t h a n 3 m i n t e r v a l y i e l d i n g no ammonites. Posidonotis  semiplicata  was not  found in place. T h e i n t e r v a l between Levels 10 and 11 is poorly exposed.  3.3.3  SKIDEGATE  INLET  AREA  M A U D E ISLAND (SECTION M) T h e measured section consists of tectonically disrupted intervals separated b y covered areas directly southwest of Section 8 of CAMERON and TIPPER (1985) on the south shore of M a u d e Island. Despite the lack of a continuous section the presence of A r n o u l d i , V a r i a n s , Harbledownense, and R e c o g n i t u m Zones can be  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  28  _2 %  Z  O  <  c  cn in tu  Z  U  O  v.  .._  C  c r  Q .  r—  I  > u  rS  (9  U  u  :_c  ic  b> m  ZONE  C  ,—  </•.  13  i/>  k.  i»  C  4J O  O  5  a>  U  < < < <  u  0  (J  a.  Harbledownense  20  -6  en  a z  Varians  < _i  Q Z < cn  -3 10  Figure 3-9  -1  Biostratigraphy of Section I at Yakoun River, central Graham Island.  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  Figure 3-10 Island.  Biostratigraphy of Section L at Ghost Main Roadcut, central Graham  29  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  30  proved ( F i g 3-11). T h e longest u n b r o k e n sequence comprises overturned and steeply d i p p i n g beds of the R e c o g n i t u m Zone i n c l u d i n g the t r a n s i t i o n of the Sandilands and G h o s t Creek F o r m a t i o n s . It is exposed at the westernmost tip of the outcrop and t r u n c a t e d below but presumably very near to the base of the I m l a y i Zone.  S A N D I L A N D S I S L A N D ( S E C T I O N N) T h e type locality of the S a n d i l a n d s F o r m a t i o n (CAMERON and TIPPER, 1985) is tectonically complex and was not studied i n detail. Arnioceras  cf. arnouldi  and A. ex gr. ceratitoides  indicates the presence of the  A r n o u l d i Zone.  A L L I F O R D B A Y R O A D ( S E C T I O N O) A n old roadcut provides poor exposure of an a p p r o x i m a t e l y 12 m section of weathered F o r m a t i o n . T h e fauna includes Badouxia  3.3.4  TASU  SOUND  cf. canadensis  and Eolytoceras  Sandilands  sp. i n d i c a t i n g the Canadensis Zone.  AREA  W 100 Q U A R R Y ( S E C T I O N P ) T h i s quarry exposes approx. 20 m of the Sandilands F o r m a t i o n w i t h another 2 m excavated i n a roadcut, p r e s u m a b l y directly u n d e r l y i n g the m a i n section. T h i s lower level yielded a single specimen of Audaxlytoceras Arnioceras  aff.  audax  cf. arnouldi,  along w i t h Arnioceras  Arnioceras  rare s c h l o t h e i m i i d Angulaticeras  spp. T h e  spp., and Juraphyllites  spezianum.  faunal  assemblage  cf. transylvaniens,  i n the  quarry  includes  and a single specimen of the  T h e assemblage suggests the A r n o u l d i Zone.  W 160 Q U A R R Y ( S E C T I O N Q ) T h i s quarry exposes  10 m of the Sandilands F o r m a t i o n capped by a sill. T h e only indentifiable  ammonites from the section are Arnioceras  ex gr. ceratitoides  and A. s p p . . D e e p l y weathered float from the  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  Z  < CZ 0  u_  ZONE  cn cn  U X  i «  g  11 y 3  u ^ u  J  5 -  - i~ — a. A —  -5 - — JJ- i c £. a. < < a.  1— "30"  U  31  - * — a:  ~ 8  u  .- C  Recognitum  29  • Z <  i  G Z < cn  10  0 10  Harbledownense  !T?-r".—T —  ^  _  Varians  .  ^ >s />  Arnouldi  0 10  Arnouldi  Figure 3-11  Biostratigraphy of Section M on Maude Island.  BIOSTRATIGRAPHY  32  AND BIOCHRONOLOGY  quarry also yielded well preserved specimens of Arnioceras  arnouldi.  T h e section can be assigned to the  A r n o u l d i Zone.  M E T R I C M A I N R O A D C U T (SECTION R) A m m o n i t e s were collected from a roadcut Sandilands F o r m a t i o n y i e l d e d Arnioceras  arnouldi  b y S. TAITE. A t y p i c a l l y t h i c k sandstone beds of the a n d A. cf. oppeli, indicative of the A r n o u l d i Zone, along  w i t h an u n u s u a l b e n t h i c assemblage consisting o f gastropods and coral fragments.  3.3.5  KUNGA  ISLAND  N O R T H S H O R E ( S E C T I O N S) A long a n d generally narrow i n t e r t i d a l bench a n d shoreline exposure is cut b y numerous dykes a n d faults; a few intervals  are covered  ( F i g . 3-12). T h i s is the type  section of the K u n g a  F o r m a t i o n of  SUTHERLAND BROWN (1968), where the Sadler, P e r i l a n d the lower part of the Sandilands F o r m a t i o n s are also represented. F a u l t s caused s m a l l scale repetitions a n d / o r omissions i n the section, b u t do not upset the ammonite succession. A c u m u l a t i v e thickness of over 400 m of uppermost H e t t a n g i a n to S i n e m u r i a n rocks was measured. T h e beds u n d e r l y i n g the Canadensis Zone d i d not yield macrofossils b u t a L a t e H e t t a n g i a n age is proved b y radiolarians ( E . S . CARTER, pers. c o m m . , 1990). T h e Canadensis Zone together w i t h the next higher four zones are well developed. T h e Harbledownense Zone is truncated b y a massive dyke forming a point at the southeastern end o f the section.  S O U T H SHORE (SECTION T) Exposures on the south shore of the island are similar to those on the n o r t h shore. T h e S i n e m u r i a n s t r a t a of the " C o r o n i c e r a s " Zone are separated  from the U p p e r H e t t a n g i a n b y a covered i n t e r v a l ; the  Canadensis Zone is o m i t t e d . T h e couplet of the A r n o u l d i a n d V a r i a n s Zones is repeated,  possibly also  encompassing several m i n o r tectonic breaks ( F i g . 3-13). T h e upper part of the Harbledownense Zone is  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  33  SANDILANDS  mrnrn  o < •J : < < : i'; :  < <  |_  <  :  CO Ol  co  o o  e  THICKNESS  o  •1:1  '•  TT  11  KJ  o  I J.I: : I  < <  FORMATION  9> •  1  :  1  '••'.i.'.'.  " t i l l •  •• '  1  t^.,i'j  \ i,' • ' • Mi?™  ri'lV:':'  : i :; I;I  li  "'  r-»  p  u 3 SJ  C It  I  n o n  it  LEVEL Vermiceras sp. indet. Badouxia canadensis Angulaticeras sp. Badouxia columbiae Eolytoceras c i . tasekoi Sulciferites ? sp. Juraphyllites cf. transyivanicus Juraphyllites sp. indet. Arnioceras arnouldi Arnioceras sp. indet. Arnioceras cf. speciosum Arnioceras ex gr. ceratitoides Asteroceras all", margarita Asteroceras sp. indet. Arnioceras cf. oppeli Asteroceras cf. saltrirnsc Epophioceras aff. carinalum Plesechioceras ? aklavikense Tetraspidoceras paciiicum Plesechioceras ? harbledownense Paltechioceras sp. indet. Paltechioceras aif. boehmi  0•  n  LITHOLOGY  3 0  c  -t  <  (t  a. o  3  S 3  Figure 3-12  Biostratigraphy of Section S on Kunga Island.  N  o Z  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  34  SANDILANDS  1  'iV;  FORMATION THICKNESS  e  TT  • r . •JJ-.r.-i MM' I  ! I I  II  ! i : : : | |  LITHOLOGY  I I.Mi  •v . ; .  T T  I  1  l» 1  V;' v. 1111 I  I  LEVEL Coroniceras ? sp. Angulaticeras cf. ventricosum Juraphyliites cf. transvlvanicum luraphyliites sp. indet. Arnioceras sp. indet. Arnioceras ex ur. ceratitoides Arnioceras arnouldi Arnioceras miserabiic Arnioceras cf. oppeii Arnioceras cf. densicosta Asteroceras aff. margarita Phyiloceras spp. Arnioceras ex gr. mendax Arnioceras cf. speciosum Adnethiceras cf. adnethicum Asteroceras cf. saltricnsc Asteroceras sp. indet Gieviceras sp. indet. Plesechioceras yakounense Plesechioceras ? harbiedowtienstPosidonotis semiplicata luraphyliites afl. nardii Crucilobiceras ? sp. indet. Phricodoceras ? sp. Tropidoceras sp.  n c  I > 3  33  < '5' 3  3  O  <  rt Q. O ?  3 rt 3  Figure 3-13  rt O  C era  3_ C  3  Biostratigraphy of Section T on Kunga Island.  N  oZ m  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  35  affected by contact metamorphism by two major dykes and therefore devoid of interpretable fossils. The Recognitum Zone is proved by sporadic ammonoids and Posidonotis semvplicata and the contact with the Imlayi Zone is apparently conformable. A substantial Lower Pliensbachian section extends towards the eastern tip of the island (SMITH et al., 1990).  3.4  L O C A L C O R R E L A T I O N A N D ITS G E O L O G I C A L IMPLICATIONS  Exposures of the Sandilands Formation are widespread throughout the islands but they typically  Figure 3-14 Biostratigraphic correlation between the studied uppermost Hettangian to lowermost Pliensbachian section of the Queen Charlotte Islands.  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  36  consist of faulted blocks juxtaposed with each other or bounded by other rock units. Because of the lack of laterally persistent marker beds biostratigraphy is the most useful correlation tool. Correlation of the measured sections is illustrated on Fig. 3-14. Although the assignment to certain zones is almost always unambiguous, the placement of parts of sections within the zones is in some cases tentative. Such a high resolution correlation will provide a valuable time-frame for any future sedimentological study of the Sandilands Formation.  KENNECOTT POINT  YAKOUN RIVER  NW  32 35  35  Canadensis  KUNGA ISLAND  Reco Harbledownense  36  SE  49  45  Figure 3-15 Lateral thickness changes of selected zones in measured sections. Thickness is indicated in meters.  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  3.4.1  THICKNESS  ESTIMATES.AND  37  TRENDS  T h e S i n e m u r i a n sedimentary succession is most completely preserved on K u n g a Island but there it is pieced together from tectonically d i s t u r b e d fragments  even  present i n Sections S and T . S t r u c t u r a l  complexity of the sections frequently results i n repetitions or losses, m a n y of t h e m s m a l l enough to be beyond the l i m i t of biostratigraphic resolution. T h u s the t o t a l thickness of the uppermost H e t t a n g i a n to lowermost P l i e n s b a c h i a n rocks can o n l y be estimated. After m a t c h i n g the two sections a m i n i m u m thickness of 310 m was calculated, assuming t h a t all the proven a n d suspected faults duplicate parts of the sections unless proven otherwise b y the fauna. A m a x i m u m estimate f r o m the opposing premise is 490 m . T o suggest 385 m as a reasonable value w i t h i n these brackets remains somewhat subjective relying on weighing the likelihood of biostratigraphic and field relationship of the faulted segments. T o analyze lateral changes of thickness specific zones were traced f r o m section to section. F o r a reliable measurement  a zone must be present i n a s t r u c t u r a l l y simple setting w i t h b o t h its lower and upper  boundaries well defined. O n l y i n a few places are these criteria met ( F i g . 3-15). A p p a r e n t l y the thickness increases consistently from northwest to southeast between 10 to 40%. Together w i t h the more sudden eastwest lithofacies changes discussed i n chapter 2.2.2, this p a t t e r n may suggest that the source area of the distal turbidites of the S a n d i l a n d s F o r m a t i o n laid to the southwest.  3.4.2  THE  CONTACT  OF THE SANDILANDS  AND  GHOST  CREEK  FORMATIONS  T o draw the b o u n d a r y between the two formations is often difficult due to the gradational nature of the contact. T h e t r a n s i t i o n from the more i n d u r a t e d , flaggy Sandilands F o r m a t i o n to the recessive, fissile Ghost Creek F o r m a t i o n usually occurs w i t h i n an i n t e r v a l of several meters. However, the tuffaceous  and  minor graded sandstone interbeds characteristic of the Sandilands F o r m a t i o n infrequently recur i n the lower part of the G h o s t Creek F o r m a t i o n .  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  38  NW  SE Yakoun  Maude  Kunga  River  Island  Island  Whiteavesi  bJ UJ  Imlayi  m o  •trier:  Recognitum  m. Q z  Harbledownense Q Z <  LJJ  or  2.9.2.  o  I—  CO  o  o  X  O  X  CO Z  CO Q  z  Q Z < CO  < _J O Z <  tn-  cn  Figure 3-16  Diachronism at the contact of the Sandilands and Ghost Creek Formations.  The resolution of our ammonite biostratigraphy is sufficient to demonstrate the diachronous nature of the contact (SMITH et al., 1990; TIPPER et al., 1991). The age of the contact is constrained in three sections (Fig. 3-16). At Yakoun River (Section H) the transition occurs in the lower part of the Recognitum Zone, on Maude Island (Section M) in the upper part of the Recognitum Zone, whereas on Kunga Island (Section T) it is found near the base of the Whiteavesi Zone (which overlies the Imlayi Zone).  3.5  C O R R E L A T I O N A N D BIOCHRONOLOGY  In this section a correlation of the Queen Charlotte zones with other areas in western North America and possibilities of intercontinental correlation with the Northwest European and Mediterranean Provinces  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  39  (Fig. 3-17), South America, and other parts of the world are discussed. The problem of the Sinemurian stage boundaries in the Queen Charlotte Islands is also addressed.  3.5.1  The Canadensis Zone and the Hettangian/Sinemurian  boundary  The Canadensis Zone of FREBOLD (1967) is defined by its diverse assemblage and particularly  STAGE  abundant index ammonite. It is widespread and easily recognizable in many areas (Alaska: IMLAY, 1981;  CL  NW EUROPE ZONE JAMESON 1  SINEMURIAN  RARICOSTATUM OXYNOTUM OBTUSUM TURNERI SEMICOSTATUM BUCKLANDI X  ANGULATA  SUBZONE JAMESONI BREVISPINA POLYMORPHUS TAYLORI APLANATUM MACDONELLI RARICOSTATUM DENSINODULUM OXYNOTUM SIMPSONI DENOTATUS STELLARE OBTUSUM BIRCHI BROOKI SAUZEANUM SCIPIONIANUM REYNESI BUCKLANDI ROTIFORME CONYBEARI COMPLANATA EXTRANODOSA  QUEEN CHARLOTTE NORTHERN ALPS ISLANDS IMLAYI RECOGNITUM 1 » L__ \ _ /  \_7 I l l l  W 1V1  HARBLEDOWNENSE  VARIANS  ARNOULDI  "CORONICERAS" CANADENSIS  ROTIFORME MARMOREUS MEGASTOMA  Figure 3-17 Approximate correlation of the proposed latest Hettangian to earliest Pliensbachian ammonite assemblage zones with the northwest European and Alpine zonations. (Northwest European zonation after DEAN et al., 1961; Alpine Zones after WAHNER, 1886).  40  BIOSTRATIGRAPHY AND BIOCHRONOLOGY  B r i t i s h C o l u m b i a : T e l e g r a p h Creek area, FREBOLD, 1964, U n u k R i v e r , Quesnel L a k e , FREBOLD and TIPPER, 1970, Taseko Lakes area, FREBOLD, 1951, 1967; N e v a d a : GUEX and TAYLOR, 1976; O r e g o n : TAYLOR, i n prep.). T h u s it seems to be a valid chronozone o n a regional scale. A twofold s u b d i v i s i o n already noted by FREBOLD (1967) and confirmed by TAYLOR (1990) as well as by our results m a y w a r r a n t the erection of subzones after a revision of the type sections near T y a u g h t o n Creek. In N e v a d a an assemblage subjacent  to  the Canadensis Zone recorded by GUEX and TAYLOR (1976) as Zone B and b y TAYLOR (in prep.)  as  Oregonensis Zone, contains elements (Badouxia  oregonensis,  Metophioceras  aff. rursicostatum,  Eolytoceras  guexi) recognized i n the lower part of the Canadensis Zone i n the Queen C h a r l o t t e Islands. T h e two most restricted Vermiceras,  characteristic genera of the  i n d i s t r i b u t i o n to Metophioceras  the  Circum-Pacific  and  Canadensis western  Zone, Badouxia  North  America,  and  Eolytoceras,  are  respectively. Species of  as well as schlotheimiids p r o v i d e correlation w i t h E u r o p e . T h e T e t h y a n character  of the fauna allows comparison w i t h the M e d i t e r r a n e a n M a r m o r e u s Zone of WAHNER (1886), as p o i n t e d out b y GUEX and TAYLOR (1976). Vermiceras and S. cf. trapezoidalis  ex gr. coregonense,  V. cf. supraspiratum,  Sulciferites  marmoreus  establish ties to that zone, w h i c h is of condensed lithology at the A l p i n e localities.  T h e correlation of the  M a r m o r e u s Zone w i t h the s t a n d a r d  Northwest E u r o p e a n zonation is a  controversial subject. GUEX and TAYLOR (1976) argued for allocating most or all of it to the S i n e m u r i a n based  on  reported  occurrences  of Sulciferites  marmoreus  and  a c c o m p a n y i n g s c h l o t h e i m i i d s from  the  C o n y b e a r i Subzone. T h i s view was debated by BLOOS (1983), who showed new evidence of this species originating i n the Depressa Subzone ( A n g u l a t a Zone, U p p e r Hettangian) (BLOOS, 1988). DEAN et al. (1961) defined the base of the earliest S i n e m u r i a n C o n y b e a r i Subzone b y the first appearance of Metophioceras.  BLOOS (1989) reviewed the alternatives such as to d r a w the b o u n d a r y at the  base of the M a r m o r e u s Zone or at the contact of the C o m p l a n a t a and Depressa subzones. He retained the t r a d i t i o n a l view w i t h the necessary modification of the definition of the C o n y b e a r i Subzone i n order conform w i t h the assemblage zone concept, since forerunners of Metophioceras U p p e r H e t t a n g i a n (e.g. BLOOS, 1983). B a s e d on the present study the following comments can be made:  to  have been reported from the  B I O S T R A T I G R A P H Y A N D BIOCHRONOLOGY  41  - Beds i m m e d i a t e l y subjacent to the Canadensis Zone yielded Alsatites  cf. proaries  (NEUMAYR) (PI. 16, fig.  5), documented by WAHNER (1886) from the A l p i n e M e g a s t o m a Zone below the M a r m o r e u s Zone. - T h e assemblage of Vermiceras trapezoidalis  cf. supraspiratum,  V. ex gr. coregonense,  Sulciferites  marmoreus,  and S. cf.  i n the Canadensis Zone allows good comparison w i t h the T e t h y a n M a r m o r e u s Zone.  - T h e i n c o m i n g of Metophioceras  aff. rotarium  and Metophioceras  spp. i n the upper part of the Canadensis  Zone suggests correlation w i t h the C o n y b e a r i Subzone of Northwest E u r o p e . - T h e first appearance of Coroniceras  ? spp. a n d Arnioceras  sp. (characteristic of the B u c k l a n d i Subzone i n  E u r o p e ) is s t r a t i g r a p h i c a l l y only approx. 10 m above the last occurrence of Badouxia  canadensis.  Consequently, the H e t t a n g i a n / S i n e m u r i a n b o u n d a r y (sensu DEAN et al., 1961 and BLOOS, 1989) should be placed w i t h i n the Canadensis Zone. T h e best a p p r o x i m a t i o n is to tie it to the i n c o m i n g of Metophioceras Badouxia  aff. rotarium  columbiae.  a n d Metophioceras  spp. w h i c h nearly coincides w i t h the first appearance of  S i m i l a r views are expressed b y T A Y L O R (1990) based on d a t a from N e v a d a .  T h e C i r c u m - P a c i f i c d i s t r i b u t i o n of Badouxia northeast Siberia. canadensis,  canadensis  permits correlation w i t h S o u t h A m e r i c a and  In A r g e n t i n a this zone was recognized by RlCCARDI et al. (1989) based on  Metophioceras  cf. rursicostatum,  Sulciferites  cf. marmoreum,  and Vermiceras  Badouxia  sp., very close to  our i n t e r p r e t a t i o n . These authors s i m i l a r l y correlated it w i t h the upper part of the A n g u l a t a and lower part of the B u c k l a n d i Zones (RlCCARDI et a l , 1990, C h a r t 1). O t h e r S o u t h A m e r i c a n records are more controversial. Badouxia  canadensis  was recognized i n C h i l e  b y HlLLEBRANDT (1981, 1987, 1991) and QUINZIO SINN (1987). T h e i r correlation w i t h the s t a n d a r d Liasicus Zone ( M i d d l e H e t t a n g i a n ) is based on the cooccurrence w i t h Alsatites misidentified Vermiceras  (Paracaloceras)  cf. platystoma  w h i c h is p r o b a b l y a  as p o i n t e d out by TAYLOR (1990 and i n prep.). Similar forms are  k n o w n from the Canadensis Zone of N e v a d a ( T A Y L O R , 1990). F r o m northeast S i b e r i a REPIN (1977) reported "Psiloceras" ("Franziceras") s i m i l a r l y correlated w i t h the Liasicus Zone o n the basis of Waehneroceras. Discamphiceras  sp. are  also f o u n d  i n this assemblage  (REPIN,  Alsatites  canadense  from a unit  cf. coregonensis  1988) s u p p o r t i n g correlation w i t h  and the  BIOSTRATIGRAPHY  AND  Canadensis Zone. A s Vermiceras  BIOCHRONOLOGY  coregonense  42  has been found nowhere else as low as the Liasicus Zone, the  age assignment of the Siberian assemblage may need revision.  3.5.2  The "Coroniceras"  Zone  T h i s zone is so poorly represented subjacent  and  superjacent  units  can  i n the Q u e e n C h a r l o t t e Islands t h a t its separation from the  o n l y be  defended  from  a regional perspective.  assemblages are k n o w n between the Canadensis Zone a n d beds w i t h a b u n d a n t Lakes area (lower part of Arietites  Arnioceras  Rich  ammonite  from the Taseko  -beds of FREBOLD, 1951) and from N e v a d a (Zone C of TAYLOR, 1986;  T r i g o n a t u m and I n v o l u t u m Zones of TAYLOR, i n prep.). Coroniceras  is the most a b u n d a n t  and diverse  genus i n b o t h cases. Its m u c h reduced frequency i n the Queen C h a r l o t t e Islands may be explained by ecological and facies factors, (WESTERMANN, 1990). In  as a deeper water  Europe  Coroniceras  b a s i n a l environment is far  more  abundant  was not  preferred  i n t h e . inner  b y this genus  shelf facies of  the  Northwest E u r o p e a n P r o v i n c e t h a n in the M e d i t e r r a n e a n localities. T h e scarcity of Coroniceras  ? spp. i n the s t u d y area permits o n l y gross correlation w i t h the upper  part of the s t a n d a r d B u c k l a n d i Zone and w i t h the A l p i n e Rotiforme Zone.  3.5.3  The Arnouldi  Zone  T h i s zone is recognized b y the preponderance of different species of Arnioceras.  Similar  Arnwceras-  d o m i n a t e d faunas are k n o w n from several areas i n western N o r t h A m e r i c a , s u c h as A l a s k a (IMLAY, 1981), Y u k o n and B r i t i s h C o l u m b i a (localities and references listed in detail in FREBOLD and TIPPER, 1970), a n d Nevada  (HALLAM,  1965, SMITH,  synonymous Arniotites) Arnioceras  1981). I n  some  cases  Arnioceras  species  ( i n c l u d i n g those  of  the  need to be restudied before their ranges can be c o m p a r e d . '  in Northwest E u r o p e ranges from the B u c k l a n d i Subzone t h r o u g h the O b t u s u m Zone  and it is p a r t i c u l a r l y abundant in the S e m i c o s t a t u m Zone. S u b z o n a l subdivisions in this and the  superjacent  BIOSTRATIGRAPHY  A N D BIOCHRONOLOGY  43  T u r n e r i Zone, however, are based on species of other genera such as Coroniceras, Caemsites,  a n d Microderoceras,  Agassiceras,  u n k n o w n from the s t u d y area except for Coroniceras.  Zone can be correlated b r o a d l y w i t h the standard  Euagassiceras,  T h u s the A r n o u l d i  S e m i c o s t a t u m a n d T u r n e r i zones b u t the d i s t i n c t i o n of  equivalents of these N o r t h w e s t E u r o p e a n zones i n the local succession is not possible. F a u n a s correlative w i t h the T u r n e r i Zone are not k n o w n i n N o r t h A m e r i c a w i t h the possible exception of the Taseko Lakes area (H.W. TIPPER, pers. c o m m . ) . T h i s zone is not well characterized even i n continetal E u r o p e (BLOOS, 1984b) and it is difficult to prove i n the M e d i t e r r a n e a n faunas (GECZY, 1972). T h e A r n o u l d i Zone compares favorably w i t h the ^ r n i o c e r a s - d o m i n a t e d M e d i t e r r a n e a n assemblages such as the Assemblage F a n d G of BRAGA et a l . (1984b) from S p a i n . T h e stratigraphic significance of a d d i t i o n a l , rare elements (Adnethiceras Angulaticeras  spezianum)  cf. adnethicum,  Audaxlytoceras  cf. audax,  Tragolytoceras  ? sp.,  is poorly understood.  C o m m o n Arnioceras  faunas i n the C i r c u m - P a c i f i c region (such as the W e s t a n d Southwest  Pacific  localities listed b y SATO, 1957, 1975) provide further possibilities for correlation of the A r n o u l d i Zone. In S o u t h A m e r i c a the equivalent of the S e m i c o s t a t u m Zone is recognized (HlLLEBRANDT, 1987 a n d references therein) b u t the record of the T u r n e r i Zone is scarce.  3.5.4  The Varians  The  assemblage  Zone  of Asteroceras,  Arnioceras,  a n d Epophioceras  characterizing this zone  is not  widespread i n N o r t h A m e r i c a . IMLAY (1980) does not m e n t i o n it from the conterminous U n i t e d States a n d no record exists from A l a s k a (IMLAY, 1981). SMITH (1981), however, reports Epophioceras (Eparietites)  and  f r o m N e v a d a assigning it to the upper part of his Ceratitoides Zone. Asteroceras  different localities i n B r i t i s h C o l u m b i a (FREBOLD a n d TIPPER, 1970). Arctoasteroceras C a n a d i a n A r c t i c (FREBOLD, 1960) is closely comparable to Asteroceras  varians  Asteroceras  is k n o w n from  jeletzkyi  f r o m the  in lateral view.  T h e V a r i a n s Zone c a n be correlated w i t h the s t a n d a r d O b t u s u m Zone based on concurrent  generic  ranges despite their different species content. It shows an even greater s i m i l a r i t y to M e d i t e r r a n e a n faunas  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  44  equivalent of the O b t u s u m Zone as o u t l i n e d from H u n g a r y (GECZY, 1971, 1972) and S p a i n (Assemblage H : BRAGA et al., 1984b). T h e record f r o m Italy is s u m m a r i z e d by DONOVAN (1990) who a t t e m p t s to prove the presence of standard subzones w i t h o u t s u p p o r t i n g local stratigraphic evidence. Correlation  is possible  with  South  A m e r i c a n faunas  equivalent of the O b t u s u m Zone based on Epophioceras in RlCCARDI et al., 1990). A n o t h e r Epophioceras  3.5.5  The Harbledownense  as  HlLLEBRANDT  and Asteroceras  (1987)  recognizes  the  from C h i l e and P e r u (see references  faunula is k n o w n from A r g e n t i n a (RlCCARDI et al., 1989).  Zone  T h i s zone is characterized b y the abundance of echioceratids accompanied by oxynoticeratids i n its basal p a r t . Echioceratids are c o m m o n i n A l a s k a (IMLAY, 1981) a n d i n the Taseko Lakes area ( H . W . TIPPER, pers. c o m m ) . T h e record from H a r b l e d o w n Island (CRICKMAY, 1928, TIPPER, 1977) is similar to that of the Queen  Charlotte  Islands.  F r o m N e v a d a SMITH (1981)  documented  a rich  assemblage  of  echioceratids  assigned to his Harbledownense a n d R o t h p l e t z i Zones. T h e Harbledownense Zone i n the Queen C h a r l o t t e Islands is d r a w n i n a different sense, as no cooccurrence of Plesechioceras  ? harbledownense  with  Asteroceras  has been found. SMITH'S (1981) Harbledownense Zone, correlated w i t h the uppermost T u r n e r i and O b t u s u m Zones of the standard  zonation, is considered close to our V a r i a n s Zone. T h e Harbledownense  understood here is translated  Zone as  to include SMITH'S (1981) R o t h p l e t z i Zone. A s SMITH'S (1981) local zonal  scheme remains u n p u b l i s h e d , this does not violate the law of p r i o r i t y a n d s h o u l d not lead to confusion. T h e base of the Harbledownense Zone is marked b y the first appearance of oxynoticeratids and thus can be correlated w i t h the s t a n d a r d  O x y n o t u m Zone. In N o r t h w e s t E u r o p e Oxynoticeras  simpsoni  is the  index of its lower subzone. T h e earliest echioceratids i n the Q u e e n C h a r l o t t e Islands can be assigned Plesechioceras  (P. yakounense,  P. ? harbledownense,  P. ? cf. aklavikense)  to  w h i c h i n E u r o p e first appears i n  the basal subzone of the R a r i c o s t a t u m Zone (DOMMERGUES, 1982). Palaeoechioceras,  w h i c h is the first  echioceratid to appear i n E u r o p e i n the O x y n o t u m Zone, is not k n o w n from the study area (although it is recorded from N e v a d a by SMITH, 1981). Paltechioceras,  w h i c h i n E u r o p e ranges through the R a r i c o s t a t u m  BIOSTRATIGRAPHY  AND  BIOCHRONOLOGY  45  Zone, w i t h peak abundance i n its highest subzone, here overlaps w i t h Plesechioceras lack of raricostate forms (Echioceras) (e.g. DONOVAN,  and Leptechioceras  1990). A m o n g the  species  ? harbledownense.  The  is a feature i n c o m m o n w i t h M e d i t e r r a n e a n faunas  of Paltechioceras,  P.  boehmi is k n o w n to range from  the  Raricostatoides to the A p l a n a t u m Subzone i n E u r o p e (DOMMERGUES and MEISTER, 1989, G E T T Y , 1973), whereas P. romanicum  is allocated to the highest S i n e m u r i a n (BREMER, 1965).  Plesechioceras aklavikense,  may offer an interesting correlation w i t h faunas of the C a n a d i a n A r c t i c  E. arcticum  -HlLLEBRANDT Plesechioceras  (1987) and  3.5.6  (Echioceras  of FREBOLD, 1960 and 1975) through B r i t i s h C o l u m b i a to S o u t h A m e r i c a , where reports  Plesechioceras  arcticum  cooccurring  with  forms  transitional  between  Palaeoechioceras.  The Recognitum  Zone and the Sinemurian  /Pliensbachian  boundary  T h e R e c o g n i t u m Zone yielded a distinctive assemblage between the last occurrence of  Paltechioceras  and the base of I m l a y i Zone, the basal u n i t of the P l i e n s b a c h i a n as defined by SMITH et al. (1988), who believed there was a consistently unfossiliferous i n t e r v a l between those two levels. T h e R a r i c o s t a t u m Zone in E u r o p e corresponds  to the range of Paltechioceras  (DEAN et al., 1961). SMITH et al. (1988)  presented  compelling evidence for the correlation of the base of I m l a y i Zone w i t h that of the s t a n d a r d Jamesoni Zone. T h u s the u n d e r s t a n d i n g of the R e c o g n i t u m Zone bears on the definition of the S i n e m u r i a n / P l i e n s b a c h i a n b o u n d a r y i n the Queen C h a r l o t t e Islands. T h i s is the first detailed record of the R e c o g n i t u m Zone assemblage, a l t h o u g h a biostratigraphic unit m a r k e d b y Entolium (now revised  as  balteatum was already noted by CAMERON and TIPPER (1985). T h i s a b u n d a n t bivalve  Posidonotis  semiplicata)  significance is p r o v e d locally but  is a characteristic  questionable  cooccurring w i t h Paltechioceras  of the  fauna.  Its  biostratigraphic  regionally. However, there are several examples  ranging pelagic bivalves such as the Triassic Halobia semiplicata  element  ? sp. and  or Monotis.  IMLAY (1981) documented  Crucilobiceras  M t n s . of A l a s k a , whereas CRICKMAY (1928) described Entolium  cf. crucilobatum  of short  Entolium  ?  from the W r a n g e l l  balteatum found together w i t h  Melanhippites  BIOSTRATIGRAPHY A N D BIOCHRONOLOGY  46  ? sp. (probably an echioceratid) f r o m H a r b l e d o w n Island. W h e t h e r the range of echioceratids extends higher or this bivalve appears lower i n these other localities cannot be decided. Crucilobiceras Raricostatum  Zone  ? sp. cannot i n northwest  define the  Europe  stage b o u n d a r y  (DEAN  et  as the  a l . , 1961)  and  genus first ranges up  appears i n the  to  the  basal  Jamesoni  Zone  ( S C H L A T T E R , 1980). T h e Italian occurrences of Tetraspidoceras is well represented Different  recognitum  (see s y n o n y m y ) are poorly dated. T h e genus  i n the U p p e r S i n e m u r i a n of Italy ( F E R R E T T I , 1975, PALLINI, 1986, D O N O V A N ,  species from other  1990).  M e d i t e r r a n e a n localities i n H u n g a r y suggest a J a m e s o n i Zone age ( G E C Z Y ,  1976). A n o t h e r species of the genus, Tetraspidoceras  quadrarmatum  is thought to characterize the  extreme  base of the P l i e n s b a c h i a n i n N o r t h w e s t E u r o p e ( H O F F M A N N , 1982, D O M M E R G U E S and M E I S T E R , 1989). The  two  rare  oxynoticeratids  originating  from  the  Recognitum  Zone,  though  unambiguous correlation, have closer affinities w i t h the P l i e n s b a c h i a n . T h e Radstockiceras  not  numismale  allowing group  occurs i n the basal J a m e s o n i Zone i n the type area of the stage ( S C H L A T T E R , 1977, 1980), where the U p p e r S i n e m u r i a n is m i s s i n g . B R E M E R (1965)  also found it i n the  Jamesoni Zone of A n a t o l i a above the  last  Paltechioceras. In the Q u e e n C h a r l o t t e Islands Juraphyllites  aff. nardii  occurs a b u n d a n t l y i n certain beds. However,  it is not k n o w n elsewhere i n N o r t h A m e r i c a . A l t h o u g h Juraphyllites derivative Tragophylloceras  species are generally long ranging, their  - to w h i c h the present species can be a connecting link - includes the z o n a l index  for the s t a n d a r d Ibex Zone. A s follows f r o m the above arguments,  the status of the R e c o g n i t u m Zone a n d its relation to the  S i n e m u r i a n / P l i e n s b a c h i a n b o u n d a r y cannot be satisfactorily settled yet. However, the present evidence tends to favour its allocation at least p a r t i a l l y to the earliest P l i e n s b a c h i a n .  PALEOBIOGEOGRAPHY  47  CHAPTER 4  4.1  PALEOBIOGEOGRAPHY  INTRODUCTION  Paleobiogeographic studies furthered  the understanding  of the  N o r t h A m e r i c a n C o r d i l l e r a as a  collage of several allochthonous terranes (CONEY et al., 1980). Since TOZER (1970) and MONGER and ROSS (1971) first presented fragments,  various  evidence of faunal anomalies s u p p o r t i n g major displacement of C o r d i l l e r a n c r u s t a l fossil  groups  of  Late  Paleozoic-Mesozoic age  have  been  investigated  from  a  paleobiogeographic perspective, c o n t r i b u t i n g to our knowledge of the geological h i s t o r y of the C o r d i l l e r a (see H A L L A M , 1986 and SMITH, 1989 for reviews). F a u n a l d a t a from different areas can be compared to assess their affinities and to detect p r o v i n c i a l i s m . B y this m e t h o d p a l e o l a t i t u d i n a l a n d l o n g i t u d i n a l constraints on the relative position of terranes and the craton are assessed. Jurassic a m m o n i t e p r o v i n c i a l i s m was recognized i n E u r o p e more t h a n a century ago (NEUMAYR, 1883). A m m o n i t e s are inferior to benthonic organisms for a paleobiogeographic reconstruction by v i r t u e of their nektonic mode of life and great dispersal ability. T h i s disadvantage is offset as they are widely available i n different terranes, t h o r o u g h l y s t u d i e d worldwide, and have received considerable attention due to their biostratographic  significance. T h e  cosmopolitan nature of most  S i n e m u r i a n ammonites  has  recognized (e.g. A R K E L L , 1956). Y e t beside the abundant t r u l y p a n d e m i c genera (Coroniceras, Asteroceras,  Paltechioceras,  long  been  Arnioceras,  etc.), there are a number of genera w i t h more restricted geographic d i s t r i b u t i o n  p r o v i d i n g a basis for d i s t i n c t i o n of biogeographic provinces.  4.2  EARLIER N O R T H AMERICAN SYNTHESES  A comprehensive treatment of the paleobiogeography of Jurassic a m m o n i t e faunas of N o r t h A m e r i c a is given b y TAYLOR et al. (1984). T h e i r terminology is followed here d i s t i n g u i s h i n g the Boreal, T e t h y a n , and East  Pacific  Realms. T h e  latter,  comprising the  North Cordilleran  R e g i o n , was  subdivided into  the  PALEOBIOGEOGRAPHY  48  A t h a b a s c a n and Shoshonean Provinces, of w h i c h o n l y the first existed d u r i n g the S i n e m u r i a n time. T w o informally used terms are P a n d e m i c , denoting w o r l d w i d e d i s t r i b u t i o n , and Pacific, referring to occurrences restricted to the C i r c u m - P a c i f i c m a r g i n . T h e authors recognized several T e t h y a n indicator genera from different N o r t h A m e r i c a n localities, while the A t h a b a s c a n P r o v i n c e was characterized by Arctoasteroceras  Eolytoceras  and  only.  T h e P l i e n s b a c h i a n a m m o n i t e faunas have received more attention i n the past several years and a model emerging from studies of SMITH (1983) and SMITH and TIPPER (1986, 1989) postulated a marine seaway (the H i s p a n i c C o r r i d o r ) to e x p l a i n the d i s t r i b u t i o n of c o m m o n elements of the W e s t e r n T e t h y s and the East Pacific and proposed increasing n o r t h w a r d displacement of S t i k i n i a , Quesnellia, and W r a n g e l l i a terranes. S i n e m u r i a n faunas can be used to test the p r o b a b i l i t y of extrapolation of this hypothesis (BRAGA et a l , 1989).  4.3  ASSESSMENT OF T H E QUEEN  CHARLOTTE ISLANDS  F A U N A  W i t h its 61 a m m o n i t e species allocated to 27 genera, the latest H e t t a n g i a n to earliest P l i e n s b a c h i a n fauna from the Queen C h a r l o t t e Islands is a m o n g the most diverse of its age i n N o r t h A m e r i c a , matched only by  that of the  Taseko Lakes area and  N e v a d a . D i v e r s i t y is a result  e n v i r o n m e n t a l s t a b i l i t y and tends to be c o n t r o l l e d b y paleolatitude  of niche p a r t i t i o n i n g related  to  (HALLAM, 1973). N o r t h A m e r i c a n  craton-bound faunas provide supportive evidence as diversity increases from n o r t h to south ( A r c t i c Islands: 7 genera from incomplete S i n e m u r i a n (FREBOLD, 1975); Fernie B a s i n : 7 genera from incomplete S i n e m u r i a n (FREBOLD, 1969, HALL, 1984, 1987); N e v a d a : 26 genera (SMITH, 1981, TAYLOR, 1986, 1990, and i n prep.)). T h e Queen C h a r l o t t e Islands, now at comparable l a t i t u d e w i t h the  Fernie B a s i n but  surpassing, it i n  diversity, best agrees w i t h the N e v a d a n record thus suggesting significant n o r t h w a r d displacement. D i v e r s i t y , d i s t r i b u t i o n patterns, a n d faunal s i m i l a r i t y can be studied at different taxonomic levels. T h e higher resolution of species level is c o m m o n l y offset b y inherent problems of species i n paleontology and bias due to uneven s a m p l i n g . T h e most c o m m o n practice is to use the genus as basic taxonomic unit for  PALEOBIOGEOGRAPHY  Figure 4-1  49  Histogram of the number of genera with different distribution pattern.  paleobiogeography. Family level offers less contrast for distinguishing provinces but it is commonly used in global studies of broader scope in time and fossil phyla. The faunal affinities of the Queen Charlotte Islands are analyzed in these levels using the data presented in the distribution section under each taxon in Chapter 6. All the families of Sinemurian Ammonitina are cosmopolitan in distribution but some families of Lytoceratina and Phylloceratina may serve as indicators of the Tethyan Realm. Among these the Derolytoceratidae, Analytoceratidae, and possibly the Pleuracanthitidae are recorded from the Queen Charlotte Islands. A survey of the 27 genera represented (Fig. 4-1) shows that most are pandemic, but several have Tethyan distribution (Juraphyllites, Adnethiceras,  Tragolytoceras, Audaxlytoceras, Ectocentntes,  Sunnsites,  Hyp asteroceras, P aroxynoticeras). Although the number of Tethyan indicator genera is significant, some are identified with uncertainty and most are represented by only a few individuals. The main exception is the  PALEOBIOGEOGRAPHY  50  NUMBER OF SPECIES  30  20 -  10 -  PANDEMIC  Figure 4-2  TETHYAN ATHABASCAN  EAST PACIFIC  PACIFIC  Histogram of the number of species with different distribution pattern.  rather abundant Juraphyllites. Eolytoceras is a genus found so far only in the Athabascan Province, whereas  Badouxia shows a Pacific distribution (TAYLOR et al, 1984). The results of a similar approach taken at species level are shown on Fig. 4-2. An interesting feature is that the Athabascan Province can be better delineated by endemic species of mainly Canadensis and Harbledownense Zone age. The Tethyan influence is clearly demonstrated by a large number of species. In addition to the ammonites, the bivalve Posidonotis semiplicata provides another example of an Athabascan species of a Tethyan genus (DAMBORENEA, 1989). Illustrative examples of different species distributions are plotted on Fig. 4-3. Combining biochronological results with the paleobio-geographic analysis, temporal patterns of provinciality may emerge. Tables 4-1 and 4-2 reveal that pandemic elements form a majority and the Tethyan influence is significant throughout the entire Sinemurian. Athabascan together with East Pacific  PALEOBIOGEOGRAPHY  Figure 4-3  51  V  Eolytoceras tasekoi:  •  Metophioceras rurslcostatum: EAST PACIFIC  T  Badouxia canadensis:  •  Vermiceras coregonense: TETHYAN  ATHABASCAN  PACIRC  Examples of species with different paleobiogeographic distribution.  PALEOBIOGEOGRAPHY  52  PROVINCE-* |ZONE  ATHABASCAN  EAST PACIFIC  PACIFIC  TETHYAN  PANDEMIC  Recognitum  -  -  -  3 50%  3 50%  Harbledownense  -  -  -  -  5 100%  Varians  -  -  -  1 25%  3 75%  Arnouldi  -  -  -  4 66.7%  2 33.3%  "Coroniceras"  -  -  -  1 20%  4 80%  Canadensis  1 9.1%  -  1 9.1%  3 27.3%  6 54.5%  T a b l e 4-1 T e m p o r a l p a t t e r n of genus level p r o v i n c i a l i s m i n the S i n e m u r i a n a m m o n i t e fauna of the Q u e e n C h a r l o t t e Islands.  PROVINCE-. JZONE  ATHABASCAN  EAST PACIFIC  PACIFIC  TETHYAN  PANDEMIC  Recognitum  1 16.7%  -  -  3 50%  2 33.3%  3 27.3%  1 9.1%  -  2 18.2%  5 45.5%  Varians  -  -  -  4 44.4%  5 55.6%  Arnouldi  -  -  -  6 50%  6 50%  "Coroniceras"  -  -  -  1 20%  4 80%  7 30.4%  7 30.4%  Harbledownense .  Canadensis  7 30.4%  1 4.4%  1 4.4%  T a b l e 4-2 T e m p o r a l p a t t e r n of species level p r o v i n c i a l i s m i n the S i n e m u r i a n a m m o n i t e fauna of the Q u e e n C h a r l o t t e Islands.  PALEOBIOGEOGRAPHY  p r o v i n c i a l i s m was strongest  53  i n the Canadensis  Zone and also traceable  i n the L a t e  Sinemurian-earliest  Pliensbachian.  MODELS E X P L A I N I N G T E T H Y A N F A U N A S IN T H E CORDILLERA  4.4  In the past two decades an impressive i n v e n t o r y of T e t h y a n fossils o c c u r i n g i n the C o r d i l l e r a has been built (e.g. NEWTON, 1988). Pre-Jurassic records from W r a n g e l l i a include Late Triassic corals from V a n c o u v e r Island (STANLEY, 1988), and a Monotis SlLBERLING, 1985) from the hydrozoan  Heterastridium  assemblage i n d i c a t i v e of low paleolatitude (TOZER, 1982,  P e r i l F o r m a t i o n of the  (CARTER et  Queen C h a r l o t t e Islands found together w i t h  al., 1989). There  is m o u n t i n g  evidence  of T e t h y a n  the  indicator  S i n e m u r i a n ammonites found i n various C o r d i l l e r a n localities. A p a r t from those reported from the Queen C h a r l o t t e Islands,  the  Taseko  Pseudaetomoceras,  Paradasyceras,  Lakes area and  and  N e v a d a n localities y i e l d e d  Tmaegoceras  Canavarites,  Pseudotropites,  (TAYLOR, 1990, i n prep., D . TAYLOR and H . W .  TIPPER, pers. c o m m . ) . Three different models have been proposed to e x p l a i n the occurrences of T e t h y a n fossils i n the A m e r i c a n C o r d i l l e r a . T h e simplest m o d e l developed u p o n m a i n l y pre-Jurassic  data  calls for  pantropic  d i s t r i b u t i o n facilitated by circum-equatorial currents to account for c o m m o n elements of T e t h y a n and East Pacific fossil biotas (NEWTON, 1988). Secondly, the tectonic dislocation m o d e l postulates oceanic plateaus or microcontinents i n the ancient W e s t Pacific as endemic centers w i t h T e t h y a n affinities later dismembered and swept across the Pacific by long-range tectonic dislocation due to sea-floor spreading (STEVENS, 1983, STANLEY and Y A N C E Y , 1990). F i n a l l y , from the E a r l y Jurassic o n w a r d , the faunal exchange between  the  W e s t e r n T e t h y s and East Pacific may have been facilitated b y a marine seaway termed H i s p a n i c C o r r i d o r (SMITH, 1983, SMITH and TIPPER, 1986), a forerunner of the C e n t r a l A t l a n t i c w h i c h was u n d o u b t e d l y open b y Late Jurassic time (SHERIDAN et a l , 1982). O u r ammonite d a t a from the Q u e e n C h a r l o t t e Islands do not support c o n v i n c i n g l y the long-range l o n g i t u d i n a l tectonic displacement hypothesis. Badouxia  is the only genus of w h i c h B. canadensis  is the only  54  PALEOBIOGEOGRAPHY  species found on b o t h sides of the Pacific, whereas a series of other species show A t h a b a s c a n or East Pacific d i s t r i b u t i o n i m p l y i n g o n l y a l i m i t e d amount of l o n g i t u d i n a l displacement. T o endorse the p a n t r o p i c a l dispersal, i n accord w i t h NEWTON's (1988) model, an eastward diversity attenuation  of T e t h y a n forms from the E a s t e r n T e t h y s to the East Pacific has to be demonstrated.  The  existing record from the E a s t e r n T e t h y a n region (e.g. H i m a l a y a : DlENER, 1908, T i m o r : ROTHPLETZ, 1882, KRUMBECK, 1923, J a p a n : SATO, 1954) is scarce a n d thus inadequate for this purpose. In fact the diversity of some N o r t h A m e r i c a n faunas far exceeds that from the Eastern T e t h y a n areas thus c o n t r a d i c t i n g  the  p a n t r o p i c a l model but this is certainly p a r t l y due to the lack of comprehensive studies from that region. Based purely on the faunal record, i.e. the s i m i l a r i t y of N o r t h A m e r i c a n and W e s t e r n  Tethyan  faunas, the extension of the H i s p a n i c C o r r i d o r back to the S i n e m u r i a n time is feasible, although s u p p o r t i n g geological evidence is weak (SCHMIDT-EFFING, 1980). Regardless w h i c h model is favoured, the high ratio of pandemic forms emphasizes the role ammonite paleoecology ( i n c l u d i n g l a r v a l ecology and dispersal a b i l i t y ) played together w i t h the equable climate of the Jurassic (HALLAM, 1975) in shaping coeval ammonite faunas around the w o r l d .  PALEOECOLOGY AND TAPHONOMY  CHAPTER 5  In  55  PALEOECOLOGY AND TAPHONOMY  this  chapter  a  paleoenvironmental  reconstruction  is  attempted  by  a  paleoecological and  t a p h o n o m i c a l analysis of the ammonites, associated macrofauna, and trace fossils.  AMMONITE PALEOECOLOGY  5.1  The  use  of the  Sinemurian  ammonites  of  the  Queen  Charlotte  Islands  for  environmental  reconstruction is l i m i t e d by the following factors: - A m m o n i t e death assemblages usually derive from a m i x t u r e of different habitats t h r o u g h the post-mortem drift of the shells. - M a n y aspects of functional morphology (e.g. w h o r l section, aperture, sutures, septa) are hindered by poor preservation. T h e shell size, v o l u t i o n , and ornament can be used to infer h a b i t a t . A n earlier m o d e l developed to explain the facies d i s t r i b u t i o n of four basic morphotypes  i n the Lower Jurassic (TINTANT et a l , 1982)  appears to be oversimplified. A p p l y i n g a recent synthesis on a m m o n i t e habitats (WESTERMANN, 1990) the studied fauna contains an array of neritic to pelagic and b a t h y a l forms. B e a r i n g i n m i n d that there is no u l t i m a t e l y consistent relationship between the morphotypes a n d their presumed environment (KENNEDY and COBBAN, 1976), two interesting points are w o r t h m e n t i o n i n g . Coroniceras  ? spp. do not occur a b u n d a n t l y i n the assemblage of the "Coroniceras" Zone, whereas  correlative faunas i n the Taseko Lakes area and N e v a d a are d o m i n a t e d b y this genus. Similar disparity is k n o w n from E u r o p e where i n nearshore  environments of the N o r t h w e s t E u r o p e a n P r o v i n c e  prevails but it is not p a r t i c u l a r l y a b u n d a n t i n the deeper water A l p i n e faunas. Coroniceras serpenticone, coarsely ornate shell is interpreted nearshore environments.  Coroniceras  w i t h its large,  as nekto-benthonic o r g a n i s m restricted to shallow water  PALEOECOLOGY AND TAPHONOMY  Sinemurian phylloceratids  and  assemblages lytoceratids  of  the  56  Mediterranean  comprising up  to  ammonitico  two t h i r d of the  rosso fauna  facies (e.g.  are  dominated  GECZY,  1972).  by  These  associations are interpreted as bathypelagic (ZlEGLER, 1967). A l t h o u g h the Q u e e n C h a r l o t t e Islands fauna contains sporadic phylloceratids and lytoceratids, they never f o r m a p r e d o m i n a n t part of the assemblage.  5.2  T H E P R E S E R V A T I O N OF AMMONITES  A m m o n i t e s f r o m the Sandilands and G h o s t Creek F o r m a t i o n s w o u l d not be the most wanted items of collectors and m u s e u m curators beacause of their notoriously poor preservation. T h e inferior state of preservation is a p r o b l e m for the taxonomist but it also offers clues to u n d e r s t a n d the sedimentology and diagenetical h i s t o r y of the host rock. Despite the voluminous literature on ammonites, studies dealing w i t h their preservational h i s t o r y are few. SEILACHER et al. (1976) presented a l u c i d a n d detailed treatment of Jurassic a m m o n i t e t a p h o n o m y of famous G e r m a n lithofacies. T h e preservation of ammonites is controlled by their m o r p h o l o g y and the sedimentological and diagenetic properties of the host rock. T h e recognition of the same morphotypes and analogous sedimentary environments permits the a p p l i c a t i o n of some of the results of SEILACHER et al. (1976) to the S i n e m u r i a n fauna of the Queen C h a r l o t t e Islands.  5.2.1  CASE  HISTORIES  (A)  U n i f o r m collapse M o s t of the s t u d i e d ammonites are found as impressions i n shale or siltstone. T h e ornament a n d the  outline of shell is generally discernible, but the flattened test has m i n i m a l relief. T h e phragmocone a n d the b o d y chamber are indistinguishable. T h i s is the p r e v a i l i n g preservation of the evolute, keeled, strongly r i b b e d morphotype  (e.g. arietitids, echioceratids). T h e low rate of sedimentation  d i d not  allow for significant  sediment infilling of the shells. T h e amount of sediment entering the b o d y chamber was not adequate to support it against collapse. T h e aragonitic shell was completely dissolved but the shiny black (e.g. Section D ,  PALEOECOLOGY AND TAPHONOMY  57  Level 17) or golden (e.g. Section H , Levels 17, 32) remains of the organic periostracal film are conspicuous on some specimens. F r a c t u r e s are often seen but never pervasive, suggesting that the corrugated  ornament  helped w i t h s t a n d diagenetic collapse u n t i l an advanced stage of shell dissolution. T h e collapse of the body chamber and phragmocone occurred nearly simultaneously w h e n the shell was severely attenuated, losing its rigidity. T h i s type  of preservation  is analogous  with that  of DactyUoceras  from the  P o s i d o n i a Shale  (SEILACHER et a l , 1976, fig. 5 C ) .  (B)  Two-phase collapse M o r p h o t y p e s w i t h higher w h o r l section a n d more subtle r i b b i n g behave differently under diagenetic  pressure. P h y l l o c e r a t i d s (e.g. P I . 1, F i g . 11) and o x y n o t i c e r a t i d s (e.g. PI. 13, F i g . 2) often show differential preservation as the b o d y chamber collapses first w h e n the shell is still rigid, resulting i n m a r k e d  fractures.  T h e phragmocone, more resistant due to septal support, collapses later when advanced shell dissolution left only the flexible periostracal foil. A s a result, ornament is well preserved on the b o d y chamber but masked on the phragmocone Oxynoticeras  by soft  deformation. T h e best examples of b o d y chamber fractures  and Gleviceras  are seen on large  specimens from Section H , Levels 16-17. L a c k i n g a keel or coarse r i b b i n g holding  the shell together, angular fragments often protrude b e y o n d the spiral outline. T h i s type is analogous w i t h the  "half-leaf"  Lytoceras  (C)  preservation  documented  by SEILACHER et  al. (1976) on  Harpoceras,  Phylloceras,  and  from the P o s i d o n i a Shale.  One-phase collapse w i t h infilled body chamber A n o t h e r type of differential preservation was observed on several specimens. T h e body  chamber,  although compressed, is not or only little fractured preserving significant relief, whereas the phragmocone is collapsed w i t h the o b l i t e r a t i o n of ornament i n the same manner as seen i n type B (e.g. P I . 14, F i g . 8). A complete sediment infilling of the b o d y chamber is inferred. Because of the same sediment compaction rate inside and outside of the b o d y chamber, and shell dissolution t a k i n g place simultaneously, no  two-phase  collapse occurred. Instead, reaching the flexible foil stage, the e m p t y phragmocone collapsed entirely b y soft  PALEOECOLOGY AND TAPHONOMY  deformation  while similar  soft  deformation  58  compressed  the  body  chamber  to  a limit  dictated  by  its  c o m p a c t i n g sediment infilling. It is inferred that the b u r i a l of these specimens took place d u r i n g periods of higher sedimentation rate. Specimens w i t h comparable t a p h o n o m i c a l h i s t o r y are discussed and figured from the P o s i d o n i a Shale b y SEILACHER et al. (1976, fig. 18D).  (D)  B o d y chamber steinkerns T h i s type is rather rare i n our material, recorded only i n Section R and less obviously i n Section P .  At  the first locality almost undeformed  i n t e r n a l moulds of b o d y chambers  can be recovered from  e m b e d d i n g rock (e.g. P I . 9, F i g . 1-2). C o m p l e t e specimens, however, show flattened  phragmocones.  the The  evident difference to type C is that i n this case (atypical for the S a n d i l a n d s F o r m a t i o n ) r a p i d lithification of the infilling sediment preceded the dissolution of shell, therefore  the i n t e r n a l m o u l d suffered o n l y m i n o r  compression a n d it is removable from the rock.  (E)  Shelly preservation A l t h o u g h rare, specimens w i t h preserved original or recrystallized calcitic shell do occur i n the  s t u d i e d m a t e r i a l (e.g.  PI. 16, F i g . 5). W i t h o u t exception they  concretions, i n d i c a t i n g that  early cementation  are related  to h i g h l y p y r i t i z e d beds or  precluded shell dissolution when  the  shallow  diagenetic  environment environment i m m e d i a t e l y below the sediment-water interface was most reductive.  (F)  U m b i l i c a l concretions T y p i c a l nucleus concretions cored b y ammonites or other fossil remains are u n k n o w n from  the  S i n e m u r i a n of the Q u e e n C h a r l o t t e Islands. U m b i l i c a l concretions, a peculiar t a p h o n o m i c phenomenon first described b y SEILACHER et al. (1976, p. 342, fig. 16), are a b u n d a n t  i n Section  D , Level 27. T h e upper or  lower side of the ammonites involved preserve unaltered relief and fine details of ornament on the u m b i l i c u s . Conversely, the outer whorls are flattened (PI. 5, F i g . 7, PI. 6, F i g . 8). In all cases the u m b i l i c u s can be prepared b y r e m o v i n g a light b r o w n carbonate cemented concretion. It is assumed that early cementation of  PALEOECOLOGY AND TAPHONOMY  59  the concretion preserved the original relief of a m m o n i t e shell from the effect of c o m p a c t i o n a l deformation. In the m a j o r i t y of the observed cases u m b i l i c a l concretions are attached to Vermiceras  sp., characterized by  wide w h o r l section and therefore rather deep u m b i l i c u s . It is obvious that the ammonite shells triggered or at least influenced the formation of these concretions, but  more specific diagenetic studies are needed  to  u n d e r s t a n d the m e c h a n i s m .  5.3  P A L E O E C O L O G Y OF T H E ASSOCIATED M A C R O F A U N A  5.3.1  BIVALVES  Bivalves  constitute  the  second  most  common  and  diverse macrofossil group, far  behind  the  ammonites i n abundance. T h e following forms were identified: Pseudomytiloides  sp. (PI. 17, F i g . 6)  P t e r i a c e a gen. et sp. indet. 1 (PI. 17, F i g . 3) P t e r i a c e a gen. et sp. indet. 2 (PI. 17, F i g . 4, 7) Otapiria  sp. A (PI. 17, F i g . 2, 11)  Otapina  sp. B  Lupherella  cf. boechiformis  Oxytoma  sp. ( P I . 17, F i g . 9)  Posidonotis Camptonectes Limea  7  semiplicata  (HYATT)  (HYATT) (PI. 14, F i g . 3; PI.15, F i g . 2)  (Camptochlamys)  sp. (PI. 17, F i g . 1, 5)  sp. (PI. 17, F i g . 8)  Plagiostoma  ? sp.  M o s t forms are t h i n shelled, c o m m o n l y found i n clusters or c r o w d i n g bedding planes, p r e s u m a b l y pseudopelagic i n mode of life (Pseudomytiloides,  P t e r i a c e a gen. indet, Otapiria,  Lupherella,  Posidonotis).  The  PALEOECOLOGY AND TAPHONOMY  60  r e m a i n i n g t a x a occur less frequently a n d are interpreted as epibenthonic. T h e inbenthos is n o t represented, suggesting persistent oxygen deficiency below the sediment-water interface. .  5.3.2  VERTEBRATES  N e k t o n i c vertebrate remains  are not u n c o m m o n i n the Sandilands F o r m a t i o n . F i s h scales are  widespread a n d several almost complete fish specimens were found ( P I . 16, F i g . 2). T h e lack of disintegration provides evidence for the absence of benthonic life d u r i n g anoxic periods. T h e discovery of a s k u l l a n d part of the axial skeleton of Ichthyosaurus  sp. from a loose slab found i n Section D at Level 27, a n d another p a r t i a l  s k u l l a n d rib fragments from K e n n e c o t t P o i n t is reported b y DENNISON et al. (1990).  5.3.3  STALKED  CRINOID  A unique specimen of Isocrinida gen. et sp. indet. was recovered from Section D above L e v e l 26. T h e calix a n d part of the c o l u m n , found on a weathered b e d d i n g plane, exceeds 110 c m i n length . M o r p h o l o g i c a l details of the calix necessary for a more exact identification (SIMMS, 1989) are eroded. Its closest affinities are among Pentacrvnites,  Seirocrinus,  a n d possibly  Isocnnus.  T h e extremely long a n d slender c o l u m n a n d the intact preservation of this delicate fossil  have  paleoenvironmental i m p l i c a t i o n s . T h e lack of disintegration of its c o m p l e x a n d fragile structure embedded i n dark, l a m i n a t e d shale suggests a complete lack of b i o t u r b a t i o n a n d anoxic b o t t o m conditions. T h e mode of life of similar stalked crinoids has long been the subject  of controversy. T h e most  perfectly  preserved  specimens are often found attached to driftwood suggesting pseudopelagic lifestyle (e.g. SEILACHER et a l . , 1968). T h e extremely long c o l u m n m a y have served t o increase feeding efficiency as present d a y p l a n k t o n d i s t r i b u t i o n has a peak a p p r o x i m a t e l y 10 m below the surface (SIMMS, 1986). A n alternative i n t e r p r e t a t i o n insists o n s t r i c t l y benthonic habitat for a l l pentacrinitids (RASMUSSEN, 1977). A c c o r d i n g t o this hypothesis, the function of the long stem was to raise the crown above the most oxygen-depleted b o t t o m layer of water.  61  PALEOECOLOGY AND T A P H O N O M Y  5.4  T R A C E FOSSILS  The  Sandilands  Formation  in  general  is  characterized  by  parallel  lamination  and  lack of  b i o t u r b a t i o n . Nevertheless trace fossils were observed at various levels of different localities. T h e m o d e r n ichnology is p r i m a r i l y used for the d e t e r m i n a t i o n of depositional environment using trace fossils (SEILACHER, 1978).  Earlier  assemblages  syntheses  suggesting  a  direct  relationship  between  paleobathymetry  and  trace  fossil  (SEILACHER, 1967) are n o w used w i t h caution, recognizing a more complex effect of various  ecological factors on ichnocoenoses (FREY et a l , 1990). However, the usefulness of c o m m o n l y recurring trace fossil assemblages for facies i n t e r p r e t a t i o n is widely accepted (FREY and PEMBERTON, 1984). A detailed s t u d y of trace fossils of Sandilands F o r m a t i o n is b e y o n d the scope of this work, our t r e a t m e n t is l i m i t e d to record some occurrences offering paleoenvironmental i m p l i c a t i o n s . Chondrites  was  found a b u n d a n t l y at the base of Section G , not far below the base of the Canadensis Zone. BROMLEY and E K D A L E (1984) noted that a l t h o u g h Chondrites  occurs i n a wide range of facies, it is the last persisting trace  fossil i n sequences w i t h decreasing O2 level. It is the exclusive trace fossil found i n sediments formed under severely oxygen-depleted b o t t o m conditions. It is also recorded from the subordinate b i o t u r b a t e d interbeds of the p r e d o m i n a n t l y anoxic P o s i d o n i a Shale i n G e r m a n y (SAVRDA and BOTTJER, 1989). A more  elaborate  model establishing the low oxygen level tolerance of different trace fossils is developed by SAVRDA and BOTTJER (1986). Zoophycos,  found i n Section H i n the Q u e e n C h a r l o t t e Islands, can tolerate fairly oxygen  deficient conditions. T h e same authors also observed positive correlation between  b u r r o w diameter  and  oxygenation level. A n u n i n d e n t i f i e d three-armed trace fossil (Section F ) and several other burrows (Section D ) reach 2-3 c m i n diameter, suggesting relatively higher O2 content of b o t t o m water. In Section H near L e v e l Nereites  13 meandering,  h e l m i n t h o i d - t y p e trace fossils were found, i n d i c a t i n g  ichnofacies, c o m m o n l y interpreted as b a t h y a l to abyssal (e.g. FREY and PEMBERTON, 1984). T h e  Zoophycos. ichnofacies i n the same m o d e l characterizes b a t h y a l or slope environment.  PALEOECOLOGY AND TAPHONOMY  62  RESULTS  5.5  In s u m m a r y the following results emerge from the paleoecological and t a p h o n o m i c a l analysis: - T h e scarcity of Coroniceras (predominant  (characteristic to infralittoral) as well as Phylloceras  i n bathypelagic environment)  rule out  the  two paleobathymetric  and  extremes  Lytoceras  of ammonite  habitats represented i n the studied assemblages. - Differences i n a m m o n i t e preservational h i s t o r y indicate a variable s e d i m e n t a r y and  diagenetic  regime. S e d i m e n t a t i o n rate was generally slow but increased at times. T h e diagenetic h i s t o r y of parts of the sequence also differ i n t i m i n g of cementation, p r e s u m a b l y related to f l u c t u a t i n g redox conditions i n the upper sediment layers. - T h e lack of infaunal bivalves, scarcity of epifaunal forms and preponderance  of t h i n shelled,  pseudopelagic t a x a is explained by p r e v a i l i n g anaerobic-dysaerobic b o t t o m conditions. - T h e intact  preservation of nektonic vertebrates  and  a stalked c r i n o i d  suggests the  lack of  scavangers and b i o t u r b a t i o n precluded again b y oxygen deficient conditions. T h e inferred pseudoplanktonic or alternately benthonic mode of life of the isocrinid c r i n o i d is i n accordance of this m o d e l , as i n the latter case the long c o l u m n m a y have served to raise the crown above the lowest, most O2 depleted water layers. - U n b i o t u r b a t e d and parallel l a m i n a t e d beds indicate b o t t o m conditions entirely p r o h i b i t i v e of benthonic life. B e d s w i t h  Chondrites  mark the passage of the O2 level threshold, allowing benthonic life  restricted to t a x a most tolerant to oxygen deficiency. P e r i o d i c rise of O2 level is further documented by the appearance of Zoophycos  and burrows of larger diameter.  SYSTEMATIC  CHAPTER 6  PALEONTOLOGY  INTRODUCTION  63  SYSTEMATIC PALEONTOLOGY  6.1 INTRODUCTION  A m m o n o i d s collected d u r i n g this s t u d y and supplemented w i t h some of the existing G S C collections are dealt w i t h i n this chapter. F o r the ammonoids  the most detailed and sound identification possible has  been a t t e m p t e d to form an independent t a x o n o m i c s t u d y as well as to provide raw d a t a for biostratigraphic and paleobiogeographic analysis. T h e description of one b i v a l v e of stratigraphic i m p o r t a n c e is i n c l u d e d , the other identified forms are listed i n C h a p t e r 5. The  classification of P h y l l o c e r a t i d a and L y t o c e r a t i d a is adopted from A R K E L L et al. (1957) w i t h  modifications b y W l E D M A N N (1970). T h e systematics of A m m o n i t i n a largely follows the outline given by D O N O V A N et al. (1981) w h i c h was intended to form a basis of the revised but as yet u n p u b l i s h e d edition of the Treatise on Invertebrate  Paleontology. Special reference is made to other authors wherever deviation  from this classification is needed i n the light of more recent work (e. g. B L O O S , 1988 for the schlotheimiids). Due  to its poor preservation (e. g. sutures are seldom preserved) the s t u d i e d m a t e r i a l is not suitable for  resolving classification problems. However, i n some cases comments are made on such questions. The c o m m o n mode of preservation of ammonites i n the Sandilands F o r m a t i o n is as flattened i n t e r n a l moulds resulting i n significant i n f o r m a t i o n loss, especially for v e n t r a l features and w h o r l section. T h e extensive use of open nomenclature is therefore inevitable. T h e recommendations of B E N G T S O N (1988) are followed regarding the m e a n i n g and s y n t a x of signs of open nomenclature. O n e exception is the cf. and ? where the usage of M A T T H E W S (1973) is preferred, i . e. cf. means u n c e r t a i n t y m a i n l y due to incomplete preservation whereas ? is used to express u n c e r t a i n t y because of provisional identification. S y n o n y m y lists are composed according to the suggestions of M A T T H E W S (1973) w i t h the  type  m a t e r i a l indicated b y an asterisk. Specimens seen are m a r k e d w i t h " v " . If a recent revision of a t a x o n is available and accepted, reference is made to it as " w i t h s y n o n y m y " .  SYSTEMATIC  INTRODUCTION  PALEONTOLOGY  64  T h e measurements and the descriptive morphological terms conform w i t h those used b y SMITH (1986). S t a n d a r d  abbreviations  are also adopted  from there ( F i g . 7-1). T h i s enables computerized  management on the studied m a t e r i a l using the A M M O N database. T h e list of abbreviations  data  used is as  follows: D M A X - M a x i m u m measurable  diameter  D  - Diameter at w h i c h other measurements were taken (if different from D M A X )  UD  - U m b i l i c a l diameter  U  - U D / D * 1 0 0 ; R a t i o of u m b i l i c a l diameter and diameter  WH  - W h o r l height  PRHW  - N u m b e r of p r i m a r y ribs per half w h o r l  SRHW  - N u m b e r of secondary ribs per half w h o r l  THW  - N u m b e r of tubercles per half w h o r l  U R H W - N u m b e r of u m b i l i c a l r i b ends per half w h o r l V R H W - N u m b e r of v e n t r a l r i b ends per half whorl VURR  - R a t i o of v e n t r a l a n d u m b i l i c a l rib ends ,  T h e last three parameters are i n t r o d u c e d for the description of s c h l o t h e i m i i d r i b b i n g following the practice of BLOOS (1979, 1988). T h e y are suitable to characterize a r i b b i n g p a t t e r n w i t h irregular bifurcation and secondary r i b intercalation. D u e to the two-dimensional preservation and the prevailing morphology of A r i e t i t i d a e ( i . e. simple r i b b i n g on evolute shell), r i b frequency curves are effective tools for identification. Since r i b density  often  changes throughout ontogeny, it is i m p o r t a n t to o b t a i n rib counts on inner whorls as well. A s the diameter of inner whorls cannot be accurately measured due to w h o r l overlap, u m b i l i c a l diameter is used to plot against the n u m b e r of p r i m a r y ribs per half w h o r l . T h i s is a departure from the m e t h o d used b y other workers, e. g.  GUERIN-FRANIATTE (1966) a n d GETTY (1973).  PHYLLOCERATINA  SYSTEMATIC  PALEONTOLOGY  6.2.  S Y S T E M A T I C DESCRIPTIONS  ORDER AMMONOIDEA SUBORDER  65  ZlTTEL, 1884  P H Y L L O C E R A T I N A A R K E L L , 1950  S U P E R F A M I L Y P H Y L L O C E R A T A C E A E ZlTTEL, 1884 F A M I L Y P H Y L L O C E R A T I D A E ZlTTEL, 1884 G E N U S Phylloceras  T Y P E S P E C I E S - Ammonites  heterophyllus  SUESS, 1865  SOWERBY, 1820, b y original designation.  D E S C R I P T I O N - Involute forms w i t h compressed w h o r l section a n d s m a l l u m b i l i c u s . F i n e ornamentation on shell surface what is usually not preserved o n i n t e r n a l m o u l d .  AGE  A N D DISTRIBUTION  - A long ranging genus ( S i n e m u r i a n to V a l a n g i n i a n ) w i t h a world-wide  d i s t r i b u t i o n . P a r t i c u l a r l y a b u n d a n t i n some T e t h y a n faunas, especially i n the c i r c u m - M e d i t e r r a n e a n region.  Phylloceras  sp.  PI. 1, F i g . 4  M A T E R I A L - O n e well preserved specimen i n siltstone.  MEASUREMENTS SPECIMEN NO. C-156980/21  DMAX 14.2  UD 2.0  U 14.3  WH 6.9  WW 4.5  PHYLLOCERA  SYSTEMATIC PALEONTOLOGY  TINA  66  D E S C R I P T I O N - Involute shell of small size. W h o r l of ellipsoid section, u m b i l i c a l w a l l low w i t h r o u n d e d shoulder. F l a n k s convex, venter rounded. O r n a m e n t consisting of very fine striae.  D I S C U S S I O N - T h i s specimen does not allow specific identification n o t w i t h s t a n d i n g its relatively good preservation.  O C C U R R E N C E - K e n n e c o t t P o i n t , section D , level 27; from the top of the Canadensis Zone.  F A M I L Y D I S C O P H Y L L I T I D A E SPATH, 1927 (sensu WlEDMANN, 1970) G E N U S Juraphyllites  T Y P E S P E C I E S - Phylloceras  MULLER, 1939  diopsis, GEMMELLARO, 1884, b y original designation.  D E S C R I P T I O N - M i d v o l u t e forms w i t h angular u m b i l i c a l shoulder. Inner whorls usually s m o o t h or w i t h widely spaced constrictions. Coarse r i b b i n g on venter and upper flanks characteristically develops o n b o d y chamber only, w h i c h often shows egression.  REMARKS  - T h e r e have  been  nearly twenty  n o m i n a l species  assigned  to  luraphyliites.  Taxonomical  problems arise from the,lack of designated types i n m a n y cases a n d the different w i d t h of the species concept employed b y different authors. A  modern comprehensive revision w o u l d be necessary to solve the current  problems, some of w h i c h are mentioned i n the discussions below.  A G E A N D D I S T R I B U T I O N - T h e genus occurs i n S i n e m u r i a n a n d P l i e n s b a c h i a n of the T e t h y a n r e a l m . In E u r o p e , where it is best documented, it is a b u n d a n t i n the M e d i t e r r a n e a n region but becomes less frequent n o r t h w a r d a n d v i r t u a l l y absent i n the Northwest E u r o p e a n province. Occurrences i n other parts of the w o r l d  SYSTEMATIC  include records  PALEONTOLOGY  from  PHYLLOCERATINA  North America (Nevada:  SMITH, 1981; M e x i c o :  67  ERBEN,  1956),  South America  ( A r g e n t i n a : HlLLEBRANDT, 1987), Soviet F a r E a s t (SEY and KALACHEVA, 1988), C h i n a ( G u a n g d o n g region, WANG and SMITH, 1986) and the H i m a l a y a s (DlENER, 1908).  Juraphyllites  cf. limatus (ROSENBERG, 1909) PI. 1, F i g . 8  cf.* cf. cf. cf.  TYPE  1909 1923 1942 1977  Rhacophyllites limatus spec. nov. - ROSENBERG, p.35, p i . 11, fig. 10-11 Kochites limatus ROS. - FUCINI, p. 105, p i . 7, fig. 11 Rhacophyllites limatus ROSENBERG - KOVACS, p. 115, p i . 5, fig. 6 Juraphyllites limatus limatus (ROSENBERG,1909) - WlEDENMAYER, p. 37, p i . 3, fig. 4, p i . 8, fig. 8, 12, text-fig. 8j-l  - Lectotype: P I . 11, fig. 10 of ROSENBERG (1909),  deposited  i n the  Paleontological  Institute,  U n i v e r s i t y of V i e n n a (WlEDENMAYER, 1977).  M A T E R I A L - One flattened fragmentary i n t e r n a l m o u l d in shale, preserving very little relief.  MEASUREMENTS SPECIMEN NO.  DMAX  724QF/3  30.7  UD 7.7  U 25.1  WH 14.3  D E S C R I P T I O N - M e d i u m sized, m i d v o l u t e shell. E x p a n s i o n rate decreasing on last w h o r l . S m o o t h , no ornamentation is discernible.  D I S C U S S I O N - T h e poor preservation necessitates the use of open nomenclature. T h e v o l u t i o n and the lack of r i b b i n g are in good agreement w i t h the s y n o n y m i z e d material. W i t h o u t obvious egression or  apertural  SYSTEMATIC  PALEONTOLOGY  PHYLLOCERA  modification  one cannot  conclude on the ontogenetic  Juraphyllites  w i t h smooth inner whorls is not ruled out w i t h certainty.  T h e morphologically closest J. limatus  b y its prominent  TINA  stage of the i n d i v i d u a l , t h u s a larger  68  species of  species is I. stella (SOWERBY, 1833) w h i c h is readily distinguished from  constrictions. T h e smooth forms of Phylloceras  s. 1. a l l have a considerably  smaller u m b i l i c u s .  O C C U R R E N C E - T a s u S o u n d area, Section P , presumably from the A r n o u l d i Zone (collected from float).  DISTRIBUTION  - I. limatus  has been recorded from the U p p e r S i n e m u r i a n (?) of M o n t e d i C e t o n a ,  N o r t h e r n A p p e n i n e s , Italy (FUCINI, 1923); H e t t a n g i a n (?) to P l i e n s b a c h i a n of the B a k o n y M t s , H u n g a r y (KOVACS, 1942); a n d the Lower P l i e n s b a c h i a n of the H a g e n M t s , N o r t h e r n A l p s , A u s t r i a (ROSENBERG, 1909).  Juraphyllites  cf. transylvanicus  (HAUER, 1866)  PI. 1, F i g . 1-2  cf. cf. pars cf. cf. cf.  1866 Ammonites transylvanicus n. sp. - HAUER, p.192 1878 Phylloceras transylvanicum Hauer - HERBICH, p. 114, pi 20J, fig. 1 (non pi. 20H, fig. 2) 1901 Rhacophyllites transylvanicus HAUER - FUCINI, p.52, pi. 8, fig. 1-7 1908 Rhacophyllites transylvanicus Hau. sp. - VADASZ, p.323 1981 Juraphyllites cf. dorsocurvata (Fucini, 1901) - SMITH, p. 129, pi. 1, fig. 2  M A T E R I A L - 18 specimens, mostly poorly preserved, fragmentary impressions i n shale a n d siltstone.  MEASUREMENTS SPECIMEN NO. 724F/1 705E/1 724QF/1 705E/10  DMAX «58 %56 %49 47.7  UD 7.3  6.5  U ssl3  S5l2 13.6  WH 31.8 as21 20.7  PRHW %30 28 %28 27  SYSTEMATIC  PALEONTOLOGY  PHYLLOCERATINA  69  D E S C R I P T I O N - M i d v o l u t e f o r m a t t a i n i n g m e d i u m to large size for genus. A d u l t s show egression on bodychamber. E x c l u s i v e l y flattened preservation does not allow observation on w h o r l shape and venter. F i n e ribbing  develops  on  last  w h o r l b e c o m i n g slightly coarser  toward  aperture.  Ribs  gently  prorsiradiate  originating on lower part of m i d d l e flank, in some specimen gently bent forward ventrally. N o constrictions discernible.  D I S C U S S I O N - Juraphyllites  transylvanicus  is a poorly established and perhaps for this reason not frequently  cited species w i t h a brief o r i g i n a l description lacking figures and w i t h o u t a designated type. Similar better understood species include  J. diopsis and  J. libertus.  T h e first differs from J. transylvanicus  but  mainly  by its r i b b i n g being coarser on b o d y chamber, more projected ventrally and originating higher on m i d d l e flank. T h e latter is readily distinguished by the presence of widely spaced, faint constrictions. O u r specimens are more involute t h a n the ones figured by HERBICH (1878) and FUCINI (1901). A l s o the r i b b i n g appears to develop at an earlier stage o c c u p y i n g the entire last w h o r l instead of the body chamber only. / . (FUCINI, 1901), originally described as a subspecies of J. transylvanicus,  dorsocurvata  was raised to species status by  SMITH (1981) based on well preserved m a t e r i a l from N e v a d a . It is smaller t h a n the Queen C h a r l o t t e form judged from a mature specimen w i t h r o s t r u m . J. nardii has finer and sigmoidal costation.  OCCURRENCE  - Kennecott  P o i n t , Section D , Level 21, K u n g a Island, Section S and T ; from  the  "Coroniceras" Zone; T a s u S o u n d area, Section P , Level 6; from the A r n o u l d i Zone.  D I S T R I B U T I O N - J. transylvanicus  has been recorded from the T e t h y a n r e a l m in Europe: T r a n s y l v a n i a  (HAUER, 1866, HERBICH, 1878, VADASZ,1908), a n d M o n t e d i C e t o n a , N o r t h e r n Appenines, Italy (FUCINI, 1901). T h e age of the E u r o p e a n occurrences is poorly constrained but p r o b a b l y S i n e m u r i a n .  SYSTEMATIC  PHYLLOCERA  PALEONTOLOGY  Juraphyllites  aff. nardii  TINA  70  (MENEGHINI, 1853)  PI. 1, F i g . 3, 5-7  aff.  1856 Ammonites  Mimatensis  aff.  1879 Ammonites  nardii  aff.  1901 Rhacophyllites  aff.  1978 Juraphyllites  D ' O R B . - H A U E R , p . 56, p i . 17, fig. 1-3  M E N E G H . - R E Y N E S , p i . 21, fig. 12-16  nardii M G H . - FUCINI, p. 48, p i . 7, fig. 1-7 gr. nardii - V E N T U R I , p . 101, p i . 1, fig. 5  M A T E R I A L - 19 specimens preserved i n shale and siltstone i n various degrees of compression (from s l i g h t l y compressed i n t e r n a l m o u l d to flattened impressions).  MEASUREMENTS SPECIMEN NO. Y L 4 7 / 8 [M] Y L 4 7 / 7 [M]  DMAX 62.4 w60  UD 7.0 %8 6.2  Y L 4 7 / 1 0 [M]  53.6  Y L 4 7 / 7 [M]  47  7.3  ss41  6.2  1 A 5 / 1 [M]  U 11.2 ssl3  WH 30.0 «25  11.6  23.6  15.5  22.8  %15  %19  7 0 7 M / 1 [m]  36.8  7.3  19.8  16.0  P L S 2 1 / 2 [m]  34.8  7.3  20.9  16.0  PLS21/1[m]  28.6  6.8.  23.8  12.7  DESCRIPTION diameter  PRHW 34 24 35 21 «30 18  «16  - M a c r o c o n c h : Involute shell of m e d i u m to large size for genus reaching a m a x i m u m  of 65 m m . M o d e r a t e l y e x p a n d i n g whorls, b o d y chamber  s h o w i n g egression.  Umbilicus  small,  u m b i l i c a l shoulder rounded. T h e w h o r l section and the height of u m b i l i c a l w a l l cannot be j u d g e d on flattened specimens. O r n a m e n t variocostate, densely r i b b e d t h r o u g h o u t  at least the last w h o r l . P r o r s i r a d i a t e , s l i g h t l y  s i g m o i d a l ribs of rounded triangular profile o r i g i n a t i n g on lower flank, gently projected forward on upper flank crossing the venter u n i n t e r r u p t e d . W i d e l y spaced single or paired constrictions flanking a swollen rib occur i r r e g u l a r l y on phragmocone. N o a p e r t u r a l m o d i f i c a t i o n observed. Sutures not preserved. M i c r o c o n c h : A p p r o x i m a t e l y half of size of a m a c r o c o n c h , shell less involute , diameter  less t h a n 4 c m .  U m b i l i c u s wider, h i g h and steep u m b i l i c a l wall on less crushed specimens. M o r e coarsely r i b b e d , whereas  PHYLLOCERA  SYSTEMATIC P A L E O N T O L O G Y  TINA  71  1 mm  Figure 6-1  Septal suture of Juraphyllites aff. nardii. Specimen PLS21/2, drawn at  WH=15mm, x6.8.  strongly prorsiradiate constrictions more prominent than on macroconch. Sutures simple with phylloid saddle endings (Fig. 6-1). One specimen (PLS21/2) shows sutural approximation at end of phragmocone. DISCUSSION - This form cannot be confidently assigned to any established species. It shows closest resemblance to Juraphyllites nardii (MENEGHINI, 1853) as described and figured by FUCINI (1901, p.48, pi. 7, fig. 1-7), REYNES (1879, pi. 21, fig. 12-16) and VENTURI (1978, J. gr. nardii, p. 101.pl. 1, fig. 5). However,  fundamental differences exist as ribbing on J. nardii develops only on the body chamber, usually on the last half whorl whereas our specimens are ribbed throughout the last whorl. Presumably ribbing develops in an earlier growth stage, bad preservation, however, commonly obscures the details. This character points toward affinity (probable ancestorship) of Tragophylloceras. Also J. nardii has less involute (commonly midvolute) coiling. Close comparison can be based on similar variocostate ornament, sigmoidal, prorsiradiate ribbing, and irregular constrictions. Our material derived from beds of the same stratigraphic position representing almost exclusively monospecific collections from four different localities. This is a strong argument for interpreting the morphologically slightly different forms as sexually dimorph macroconch/microconch pairs. Maturity in Juraphyllites can be judged from egression on body chamber or from sutural approximation near the end of the phragmocone. Mature specimens fall into two broad groups: macrochonchs attaining large diameter and characterized by denser ribbing and smaller umbilicus; and smaller, less involute, more coarsely ribbed  SYSTEMATIC  microchonchs. T h e [M]/[m] frequency Y a k o u n River  72  PHYLLOCERATINA  PALEONTOLOGY  ratio varies significantly f r o m one locality to another: samples  at  are largely [M] d o m i n a t e d (4:1) a n d the opposite was found i n K u n g a Island (c. 1:3). T h e  relatively s m a l l number of i n d i v i d u a l s does not warrant  a statistical analysis. T h e above disparity is not  unprecedented, similar cases have been reported (for examples see CALLOMON, 1981). Beside the b i m o d a l d i s t r i b u t i o n of size a n d other morphologic variables a phylogenetic criterion should also be met before c o n c l u d i n g u p o n sexual d i m o r p h i s m : this phenomenon appears to occur i n lineages rather t h a n i n isolated t a x a (CALLOMON, 1981). N o proven examples of d i m o r p h i s m of Juraphyllites been demonstrated  yet, but the p o s s i b i l i t y was raised b y SMITH (1981) for J. dorsocurvata  and / . lunensis (DE STEFANI, 1886). HOWARTH a n d DONOVAN (1964) demonstrated E a r l y P l i e n s b a c h i a n Tragophylloceras  w h i c h is thought to have been evolved from  have  (FUCINI, 1901)  sexual d i m o r p h i s m i n  Juraphyllites.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Levels 49 a n d 52; central G r a h a m Island, Section L , Level 3; M a u d e Island, Section M , L e v e l 6; K u n g a Island, section T , Levels 56 and 60; from the upper part of R e c o g n i t u m Zone except for H / 5 2 , w h i c h is from the base of I m l a y i Zone.  Juraphyllites  sp.  P L 1, Fig. 9  M A T E R I A L - O n e specimen of mediocre preservation i n concretion.  MEASUREMENTS SPECIMEN NO. 608B/8  DMAX 35.5  UD 7.3  U 20.6  WH 17.6  SYSTEMATIC  PALEONTOLOGY  DESCRIPTION  -  PHYLLOCERA  TINA  73  M o d e r a t e l y involute shell w i t h sharp, u m b i l i c a l edges. Last w h o r l showing incipient  egression. S m o o t h up to the last half w h o r l . T h e last quarter of a w h o r l bears seven rather coarse ribs of various length, o r i g i n a t i n g o n m i d to upper flank.  D I S C U S S I O N - T h e assignment of this specimen to Juraphyllites  is supported b y the variocostate  on last w h o r l a n d the incipient egression. Specific i d e n t i t y cannot  be established  ornament  due to the incomplete  preservation of the critical part of the last w h o r l where the r i b b i n g develops. J. cf. limatus differs from this form i n retaining a smooth shell at comparable diameter.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , Level 27; from the top of Canadensis Zone.  O R D E R L Y T O C E R A T I D A HYATT, 1889 SUBORDER  L Y T O C E R A T I N A HYATT, 1889  S U P E R F A M I L Y L Y T O C E R A T A C E A E NEUMAYR, 1875 F A M I L Y L Y T O C E R A T I D A E NEUMAYR, 1875 G E N U S Lytoceras  T Y P E S P E C I E S - Ammonites  fimbnatus  SUESS, 1865  J . SOWERBY, 1817  S Y N O N Y M Y - See WlEDMANN, 1970, p. 992.  DESCRIPTION  - E x t r e m e l y evolute shell w i t h whorls of rounded or quadrate cross section.  Ornament  consisting of fine, dense riblets or g r o w t h lines a n d often widely spaced flares on shell w i t h corresponding constrictions on i n t e r n a l m o u l d .  SYSTEMATIC  LYTOCERATINA  PALEONTOLOGY  A G E A N D D I S T R I B U T I O N - Lytoceras  74  is a long-ranging genus occuring world-wide from the S i n e m u r i a n to  the U p p e r Cretaceous.  Lytoceras  sp.  PI. 1, F i g . 11  M A T E R I A L - One specimen preserved as flattened impression i n shale.  M E A S U R E M E N T S - Specimen N o . 6 0 9 H / 9 D M A X = 1 0 0  DESCRIPTION  -  Advolute  form  approximately one t h i r d of diameter.  with  rapidly  N o ornament  U D = 3 6 U=36  enlarging  whorls  WH=37  hence  visible on phragmocone  umbilicus  representing  due to crushed  only  preservation.  B o d y chamber ^ / g w h o r l long, densely covered b y fine riblets some of w h i c h stronger t h a n others at irregular intervals.  D I S C U S S I O N - T h e poor preservation renders a full assessment of the specimen impossible. T h e type species Lytoceras  fimbnatum  secernendum  is similar i n m a n y aspects but can be distinguished by its prorsiradiate ornament.  L.  STEFANI, 1886 resembles to the studied specimen i n v o l u t i o n and ornament of b o d y chamber.  Its diagnostic constrictions" on the inner whorls cannot be seen on our i n d i v i d u a l .  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , Level 17; from the Canadensis Zone.  Lytoceras  spp.  P L 1, F i g . 10,12  M A T E R I A L - 10 specimens mostly preserved as flattened i n t e r n a l moulds i n shale.  SYSTEMATIC P A L E O N T O L O G Y  Figure 6-2  LYTOCERATINA  75  Septal suture of Lytoceras sp. Specimen 611M/2, drawn at WH=17 mm,  x6.8.  DISCUSSION - Several forms are being grouped together Lytoceras spp. They all share lytoceratid affinities expressed in very evolute shell form, more or less rapidly enlarging whorls, and general lack of ornament. One specimen (611M/2) shows typical lytoceratid sutures (Fig. 6-2). Given the two-dimensional preservation, these relatively featureless forms cannot be identified with greater precision, nonetheless they provide valuable information regarding the composition of the Sinemurian ammonite fauna of the Queen Charlotte Islands. OCCURRENCE - The studied specimens originated from various levels in sections A, D, and F at Kennecott Point, from the Canadensis and "Coroniceras" zones.  GENUS Adnethiceras WlEDMANN, 1970  T Y P E SPECIES - Ammonites adnethicus HAUER, 1854, by original designation.  SYSTEMATIC  LYTOCERATINA  PALEONTOLOGY  76  D E S C R I P T I O N - A d v o l u t e lytoceratids of moderate expansion rate. W h o r l section subcircular. Massive, coarse r i b b i n g emerging gradually after a smooth stage of various d u r a t i o n . R i b s crossing venter, swollen at ventro-lateral shoulder.  R E M A R K S - A detailed treatment of the genus w i t h a list of species included is given by WlBDMANN (1970).  A G E A N D D I S T R I B U T I O N - Adnethtceras  is k n o w n f r o m the S i n e m u r i a n of the M e d i t e r r a n e a n P r o v i n c e of  E u r o p e (Spain, Italy, A u s t r i a , R u m a n i a ) . T h i s is the first record of genus from N o r t h A m e r i c a .  Adnethtceras  (HAUER, 1854)  cf. adnethicum PI. 2, F i g . 4  cf.  1970 Adnethtceras  cf. adnethicum (HAUER) - W l E D M A N N , p. 998, p i . 8, fig. 1; text-fig. 25, 27b, 3 0 K L (with synonymy)  T Y P E - H o l o t y p e : Ammonites  Adnethicus  HAUER, 1854, p i . 1, fig. 2-3, refigured by W l E D M A N N , 1970, p i . 8,  fig. 1; text-fig. 3 0 K ; deposited in the Geologische B u n d e s a n s t a l t , V i e n n a , S p e c i m e n N o . 576.  M A T E R I A L - One poorly preserved compressed e x t e r n a l m o u l d .  M E A S U R E M E N T S - Specimen N o . 7 0 6 O / 2 D M A X = 5 7 . 4  UD=27.8 U=48.4  WH=16.0  PRHW=14  (Note: Linear measurements are exaggerated due to preservational distortion.)  D E S C R I P T I O N - H i g h l y evolute  (advolute?)  shell, whorls enlarging moderately  r a p i d l y . F l a n k s convex,  u m b i l i c a l w a l l and shoulder not developed, o r i g i n a l w h o r l section likely to be inflated.Inner whorls somewhat obliterated  due to poor preservation  but  appear to be smooth. Dense, coarse r i b b i n g develops from an  SYSTEMATIC  PALEONTOLOGY  LYTOCERATINA  77  u m b i l i c a l diameter of a p p r o x i m a t e l y 7 m m . R i b s straight, rectiradiate, of high b u t rounded profile. A l t h o u g h venter not seen, ribs likely to cross over as being projected b e y o n d contour of shell on b e d d i n g plane. R i b s strengthening ventrally.  D I S C U S S I O N - Despite its poor preservation our specimen is i n general agreement w i t h the lateral views of the type m a t e r i a l . A. haueri WlEDMANN, 1970 differs b y its denser r i b b i n g a n d more slender w h o r l section.  O C C U R R E N C E - K u n g a Island, Section T , Level 32; from the top of A r n o u l d i Zone.  D I S T R I B U T I O N - A. adnethicum  is k n o w n from the A d n e t h region of N o r t h e r n A l p s , A u s t r i a , the C e n t r a l  A p p e n i n e s , Italy (WlEDMANN, 1970), a n d the B e t i c C o r d i l l e r a , S p a m (BRAGA et a l , 1984, 1985).  G E N U S Tragolytoceras  T Y P E S P E C I E S - Ammonites  altecmctus  SPATH, 1924  HAUER, 1866 b y o r i g i n a l designation.  D E S C R I P T I O N - V e r y evolute forms of s m a l l to m e d i u m size. Inner whorls smooth, b l u n t r i b b i n g developing gradually giving Capricorn appearance to outer whorls.  R E M A R K S - T h e genus is not well understood as the type m a t e r i a l is lost a n d information on suture lines is lacking. (WlEDMANN, 1970).  A G E A N D D I S T R I B U T I O N - Tragolytoceras  is k n o w n from the S i n e m u r i a n of the M e d i t e r r a n e a n P r o v i n c e  i n E u r o p e . T h i s is the first record of the genus from N o r t h A m e r i c a .  SYSTEMATIC  PALEONTOLOGY  LYTOCERATINA  Tragolytoceras  78  ? sp.  PI. 2, F i g . 2  M A T E R I A L - O n e specimen preserved as flattened i n t e r n a l m o u l d i n shale.  M E A S U R E M E N T S - Specimen N o . Y L 1 0 / 1  DMAX=29.8  UD=10.70 U=35.9  WH=9.4  D E S C R I P T I O N - V e r y evolute shell of a s m a l l diameter (3 c m ) . W h o r l s enlarging moderately r a p i d l y , hence u m b i l i c u s representing a p p r o x i m a t e l y one t h i r d of diameter. Preserved relief suggesting flattened or slightly convex flanks. Inner whorls s m o o t h up to an u m b i l i c a l diameter of 7 m m from w h i c h point coarse, blunt r i b b i n g develops gradually. R i b s o r i g i n a t i n g a p p r o x i m a t e l y at one t h i r d of flank, gently prorsiradiate and inclined forward, strongest at ventro-lateral shoulder.  D I S C U S S I O N - T h e allocation of our f o r m to Tragolytoceras  cannot be satisfactorily proven. It most closely  resembles to some of the figured specimens of the type species T. altecmctum  (especially BONARELLI, 1900,  pi. 9, fig. 1). T h e Q u e e n C h a r l o t t e specimen displays similar style of ornament more forwardly i n c l i n e d ribs. However, affinities to Arnioceras,  differing m a i n l y i n h a v i n g  suggested b y the smooth nucleus cannot be  ruled out. R i b b i n g confined to the m i d d l e a n d upper flank is not t y p i c a l for that genus. T h e only comparable form is described from the basal U p p e r S i n e m u r i a n of T u n e s i a as Arnioceras et a l . , 1986 (p. 1115, p i . 1, fig. 7-8). V e n t r a l features,  not  fieldmgoceroid.es  DOMMERGUES  available on our specimen are needed  unequivocal identification.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , L e v e l 11; f r o m the top of the A r n o u l d i Zone.  for  SYSTEMATIC  PALEONTOLOGY  79  LYTOCERATINA  F A M I L Y D E R O L Y T O C E R A T I D A E S P A T H , 1927 G E N U S Audaxlytoceras  T Y P E - Lytoceras  FUCINI, 1923  audax M E N E G H I N I , 1881, subsequent designation b y A R K E L L , 1957.  D E S C R I P T I O N - S m a l l , evolute lytoceratids w i t h low expansion rate a n d compressed w h o r l section. S m o o t h except for widely spaced constrictions on internal m o u l d corresponding to r u d i m e n t a r y ribs or flares on shell.  R E M A R K S - A thorough revision and clarification of systematic a n d n o m e n c l a t u r a l status of the genus is given b y F A N T I N I SESTINI, 1973. T h e genus was placed i n t o A n a l y t o c e r a t i d a e b y S P A T H (1927). A R K E L L (1957) assigned it to Nannolytoceratidae while most recently F A N T I N I SESTINI (1973) presented an argument for classifying it as a genus of Derolytoceratidae, this view is accepted herein. W l E D M A N N (1970) pointed out the s t r i k i n g morphological s i m i l a r i t y of Audaxlytoceras  to Trachyphyllites,  a monospecific genus only k n o w n  from the U p p e r Triassic of T i m o r . H e used it to support far-reaching evolutionary consequences  concerning  the connecting links between T r i a s s i c and Jurassic ammonoids, a view challenged b y T O Z E R (1971) based on the demonstrably controversisal age assignment of the T i m o r specimen. If the correct age is i n fact E a r l y Jurassic, Trachyphyllites  AGE  m a y be best regarded as a j u n i o r subjective s y n o n y m of  A N D DISTRIBUTION  -  Audaxlytoceras  is restricted  to the  Audaxlytoceras.  Sinemurian  to T o a r c i a n  of the  M e d i t e r r a n e a n P r o v i n c e i n E u r o p e (FANTINI SESTINI, 1973). T h i s is the first record of the genus from N o r t h America.  Audaxlytoceras  aff. audax ( M E N E G H I N I , 1881) PI. 2, F i g . 6  cf.  1927 Lytoceras sp., aff. Lytoceras audax M e n e g h . - S C H R O D E R , p. 154, p i . 9, fig. 1 1927 Monophyllites (Trachyphyllites) costatus n. sp. - A R T H A B E R , p. 141, p i . 17, fig. 3  SYSTEMATIC  ? aff.  PALEONTOLOGY  LYTOCERATINA  80  1970 Trachyphyllites costatus ARTHABER - WlEDMANN, p. 987, p i . 5, fig. 6, text-fig. 8a-b (Holotype refigured) ( w i t h s y n o n y m y ) 1973 Audaxlytoceras audax (MENEGHINI, 1881) - FANTINI SESTINI, p. 490, p i . 49, fig. 1-3 ( w i t h synonymy)  M A T E R I A L - One flattened specimen preserved i n shale.  M E A S U R E M E N T S - Specimen N o . 7 2 4 A / 1 D M A X = 2 7 . 1  UD=11.4 U=42.1  WH=8.5  PRHW=4  D E S C R I P T I O N - A d v o l u t e shell of s m a l l size. W h o r l expansion rate moderately high. Nucleus smooth, from an u m b i l i c a l diameter of 2 m m widely spaced, adorally convex r u d i m e n t a r y ribs (flares) develop. Last w h o r l bearing 8 ribs, some of t h e m flanked by a shallow constriction. 3 ribs on last ^ / g w h o r l - two of t h e m very closely spaced - possibly i n d i c a t i n g m a t u r i t y . V e n t r a l view and sutures not available.  D I S C U S S I O N - A m o n g the species assigned to Audaxlytoceras  by FANTINI SESTINI (1973), the type species  appears to be the most closely related to our form. T h e specimens figured b y FANTINI SESTINI attain slightly higher size a n d show higher w h o r l expansion rate. SCHRODER (1927) illustrated a specimen resembling the Queen C h a r l o t t e i n d i v i d u a l except for its fine, short vetro-lateral riblets. Based purely on the lateral views, very close comparison can be made w i t h the single specimen of Trachyphyllites  costatus ARTHABER. S h o u l d  it have originated from S i n e m u r i a n , not N o r i a n s t r a t a as the p r o b a b i l i t y was proposed by TOZER (1971), the two are likely to be very closely related. N o conclusion can be d r a w n without more and better  preserved  material.  O C C U R R E N C E - T a s u S o u n d area, Section P , Level 1; from the upper part of the A r n o u l d i Zone.  D I S T R I B U T I O N - A. audax is k n o w n from the P l i e n s b a c h i a n of Italy and A u s t r i a . SCHRODER'S (1927) aff. audax originated from the S i n e m u r i a n of the B a v a r i a n A l p s , G e r m a n y . found i n the U p p e r Triassic or possibly S i n e m u r i a n of T i m o r .  Trachyphyllites  costatus  A. was  SYSTEMATIC PALEONTOLOGY  LYTOCERATINA  81  F A M I L Y P L E U R O A C A N T H I T I D A E H Y A T T , 1900 S U B F A M I L Y E C T O C E N T R I T I N A E SPATH, 1927 G E N U S Ectocentrites  T Y P E S P E C I E S - Ammonites  S Y N O N Y M Y - Cosmolytoceras  CANAVARI, 1888  petersi HAUER, 1856, subsequent designation b y BONARELLI, 1900.  SPATH, 1924  D E S C R I P T I O N - E v o l u t e forms w i t h moderate w h o r l expansion rate. W h o r l section quadrate to rounded, venter broad, smooth and flattened. O r n a m e n t consisting of dense, straight or s l i g h t l y flexuous r i b b i n g of fine to m e d i u m thickness.  A G E A N D D I S T R I B U T I O N - Ectocentrites  is characteristically T e t h y a n i n d i s t r i b u t i o n . It is k n o w n from  the U p p e r H e t t a n g i a n ( ? ) - S i n e m u r i a n of the M e d i t e r r a n e a n P r o v i n c e , H i m a l a y a s , T i m o r and C h i l e . It has not been previously recorded from N o r t h A m e r i c a .  Ectocentrites  ? sp.  PI. 2, F i g . 1, 5  M A T E R I A L - 3 flattened internal moulds of b o d y chamber  fragments.  D E S C R I P T I O N - Fragments of specimens of large size, w h o r l height reaching 60 m m . C u r v a t u r e suggesting moderately wide u m b i l i c u s . Densely r i b b e d , p r i m a r y ribs s l i g h t l y flexuous, p r o b a b l y crossing venter. 2 to 4 fine secondary ribs between primaries, strongest on upper flank and near ventro-lateral shoulder.  SYSTEMATIC  PALEONTOLOGY  82  LYTOCERATINA  D I S C U S S I O N - T h e fragmentary and poorly preserved m a t e r i a l does not allow more precise identification. T h e generic assignment  is based on the style of ornament  and v o l u t i o n . Closely related specimens  illustrated b y WAHNER f r o m the M a r m o r e u m Zone of the A l p s as Ectocentrites  petersi italicus  are  CANAVARI,  1882 (1898, p. 279, especially p i . 20, fig. 1-3; p i . 2, fig. 1-2). A n o t h e r remarkably similar i n d i v i d u a l from the B u c k l a n d i Zone of T i m o r is i l l u s t r a t e d b y KRUMBECK as Ectocentrites 177, fig. 7).Reasonable c o m p a r i s o n can be d r a w n w i t h E. altiformis  sp. nov. aff. itahco  (1923, p. 110, p i .  BONARELLI, 1900 (e. g. BONARELLI,  1900, p i . 9, fig. 4; FUCINI, 1901, p i . 14, fig. 9) although this species lacks secondary r i b b i n g .  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , Level 27; from the top of the Canadensis Zone.  F A M I L Y A N A L Y T O C E R A T I D A E SPATH, 1927 G E N U S Eolytoceras  T Y P E S P E C I E S - Eolytoceras  FREBOLD, 1967  tasekoi FREBOLD, 1967, by original designation.  D E S C R I P T I O N - E v o l u t e forms of m e d i u m size, w h o r l section ellipsoid. O r n a m e n t consisting of very fine ribs arid widely spaced flares on shell w i t h corresponding constrictions on i n t e r n a l m o u l d . S u t u r e line w i t h trifid lateral lobes and p h y l l o i d saddle endings.  R E M A R K S - WlEDMANN (1970) assigned the genus to the family A n a l y t o c e r a t i d a e on the basis of s u t u r a l characteristics already emphasized by FREBOLD (1967).  AGE  A N D D I S T R I B U T I O N - Eolytoceras  appears to be confined to the uppermost  Hettangian-Lower  S i n e m u r i a n of W e s t e r n N o r t h A m e r i c a ( B r i t i s h C o l u m b i a : FREBOLD, 1967; N e v a d a : GUEX and TAYLOR, 1976, TAYLOR, 1990), i . e. the A t h a b a s c a n P r o v i n c e sensu TAYLOR et a l , 1984.  SYSTEMATIC  PALEONTOLOGY  LYTOCERATINA  Eolytoceras  83  tasekoi FREBOLD, 1967 PI. 3, Fig. 1, 4  * v  1967 Eolytoceras 1970 Eolytoceras  tasekoi n. sp. - FREBOLD, p. 14, p i . 8, fig. 1-2, text-fig. 2 tasekoi FREBOLD - WlEDMANN, p. 1007, p i . 7, fig. 4, text-fig. 9c, 30D, 31 (Holotype refigured)  T Y P E - Holotype: Eolytoceras  MATERIAL  - 6 specimens  tasekoi FREBOLD, 1967, p i . 8, fig. 2, G S C T y p e N o . 20059.  preserved  as slightly compressed  i n t e r n a l moulds in siltstone or  flattened  impressions in shale.  MEASUREMENTS SPECIMEN NO.  DMAX 89 78 75.5 49.6 49 37.8  610H/1 610B/1 611M/2 704D/1 609A/1 24B/1  DESCRIPTION egression  UD  at  U  36.2 30.5 27 18.0 18 13.3  40.7 39.1 35.7 36.3 36.7 35.2  WH 30.5 33 29.0 19.0 19.5 14.8  - V e r y evolute form of m e d i u m size. W h o r l expansion moderately r a p i d , t u r n i n g into  mature  stage.  Whorl  section  ellipsoid,  compressed,  flanks  slightly convex. F i n e ,  dense,  prorsiradiate r i b b i n g strongest on inner whorls.  D I S C U S S I O N - Specimens 6 1 0 B / 1 and 2 4 B / 1 show the best agreement w i t h the holotype. T h e specimens are w o r n i n t e r n a l moulds l a c k i n g ornament or flattened impressions identified as E. cf. Our  other tasekoi.  largest specimen show egression at a diameter over 75 m m comparable to FREBOLD's E. cf. tasekoi  (1967, p i . 6, fig. 1) w h i c h develops egression at a diameter of a p p r o x i m a t e l y 125 m m . Shallow constrictions are only rarely preserved on our i n d i v i d u a l s .  SYSTEMATIC  84  LYTOCERATINA  PALEONTOLOGY  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D and F ; K u n g a Island, Section S; from the Canadensis Zone.  DISTRIBUTION  - E.  tasekoi  was first described from the Canadensis Zone of the T a s e k o Lakes area  ( F R E B O L D , 1967) a n d it is also reported from N e v a d a ( G U E X and T A Y L O R , 1976, T A Y L O R , 1990).  Eolytoceras  ? guexi ? T A Y L O R , M S name PI. 2, F i g . 3, 7-8  T Y P E - H o l o t y p e : Eolytoceras  guexi T A Y L O R , i n prep.; Specimen N o . B 7 0 5 7 / 1 , deposited i n the Northwest  M u s e u m of N a t u r a l H i s t o r y , P o r t l a n d .  M A T E R I A L - 10 specimens, flattened  impressions, compressed i n t e r n a l moulds and an external m o u l d  preserved i n shale a n d siltstone.  MEASUREMENTS SPECIMEN NO. 609D/1 611G/3 609G/1 6101/3 610G/6 Holotype  DESCRIPTION  DMAX 127 125 86 79.2 80.2 75  UD 40 41.5 29 33.6 28.5  U 31.5 33.2 33.7  30.5  40.6  42.4 35.5  WH 45.8 50.1 34.5 24.7  PRHW 6 6 5  26.5  6 6  25  4  - V e r y evolute shell a t t a i n i n g large size. E x p a n s i o n rate moderate to h i g h . F l a n k s convex,  whorls p r o b a b l y inflated. N o ornament seen on innermost whorls, adorally s l i g h t l y convex flares developing from an early stage. 5-6 flares per half w h o r l at an u m b i l i c a l diameter greater t h a n 25 m m . V e n t r o - l a t e r a l nodes or bullae developing on ventro-lateral termination(?) of flares at later g r o w t h stage. Flares m a y be  SYSTEMATIC  85  LYTOCERATINA  PALEONTOLOGY  accompanied b y a flanking c o n s t r i c t i o n . Some specimens bearing fine riblets especially o n upper flank at large diameter. N o sutures available.  DISCUSSION  - T h e identification remains  tentative  as the holotype from N e v a d a shows more  enlarging whorls a n d less conspicuous constrictions instead of the prominent  flares  slowly  seen on the Queen .  C h a r l o t t e specimens (although this m a y be due to preservational differences). T h e diagnostic ventro-lateral nodes provide strong support for regarding t h e m conspecific. E. tasekoi differs f r o m E. ? guexi ? i n h a v i n g r i b b e d inner whorls, less well developed constrictions and lacking ventro-lateral nodes. O u r i n d i v i d u a l s are also similar to several specimens of articulatum  Analytoceras  (SOWERBY) figured b y WAHNER (1894, especially p i . 54, fig. 3, a n d p i . 58, fig. 1-3) i n their outer  whorls bearing flares a n d nodes. Nonetheless A. articulatum  c a n be easily distinguished b y its " a r t i c u l a t e d "  inner whorls ( d i v i d e d b y deep constrictions) most clearly seen o n j u v e n i l e specimens. T h e t w o species are p r o b a l y not far removed, however. F o r the above affinities the generic assignment to Eolytoceras  is tentative  the confirmation p e n d i n g o n comparison of sutures not available o n the studied specimens.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D a n d F , f r o m the Canadensis Zone.  D I S T R I B U T I O N - Besides the Queen C h a r l o t t e Islands, E. guexi is only k n o w n from the Canadensis Zone of Nevada.  SYSTEMATIC  PALEONTOLOGY  SCHL  SUBORDER  O THEIMIID  AMMONITINA  H Y A T T , 1889  SUPERFAMILY PSILOCERATACEAE FAMILY SCHLOTHEIMIIDAE G E N U S Angulaticeras  TYPE  S P E C I E S - Ammonites  lacunatus  86  A E  H Y A T T , 1867  S P A T H , 1923  Q U E N S T E D T , 1883  J . B U C K M A N , 1844; subsequent designation b y L A N G E  (1924)  ( I C Z N O p i n i o n 324).  S Y N O N Y M Y - Argoceras  S T E I N M A N N , 1925; Boucaulticeras  S P A T H , 1924; Pseudoschlotheimia  S P A T H , 1924  ( D O N O V A N et a l . , 1981).  D E S C R I P T I O N - Involute shell of usually s m a l l to m e d i u m size w i t h r a p i d l y enlarging whorls of h i g h o v a l section. V e n t r a l sulcus well developed i n juvenile stage, becoming less p r o n o u n c e d on adults. O r n a m e n t of fine a n d dense s i g m o i d ribs not crossing the venter. C h a r a c t e r i s t i c irregular a l t e r n a t i o n of b i f u r c a t i n g a n d i n t e r c a l a t i n g ribs. V e n t r a l rib ends often  accentuated.  R E M A R K S - R e c e n t l y B L O O S (1979, 1988) c o m m e n t e d on the generic systematics e m p l o y e d b y D O N O V A N and F O R S E Y (1973) a n d subsequently b y D O N O V A N et al. (1981). F i r s t he emphasized the heterogenous n a t u r e o f the closely related genus Sulciferites the u n i f i c a t i o n of Sulciferites  a n d Angulaticeras  b y using quotation marks ( B L O O S ,  1979). Later he favoured  under the latter generic n a m e on the basis of similar s u t u r a l  characteristics as already p o i n t e d out b y S C H I N D E W O L F (1962). D O N O V A N a n d F O R S E Y ' s twofold g r o u p i n g is largely based on e x t e r n a l morphology: Angulaticeras sulcus while Sulciferites  being more finely a n d densely r i b b e d h a v i n g a v e n t r a l  possesses coarser r i b b i n g . T h i s classification is retained here.  SYSTEMATIC  PALEONTOLOGY  87  SCHLOTHEIMIIDAE  A G E A N D D I S T R I B U T I O N - Angulaiiceras occurs i n E u r o p e i n b o t h the M e d i t e r r a n e a n a n d the Northwest E u r o p e a n provinces i n the Lower a n d U p p e r S i n e m u r i a n . O u t s i d e E u r o p e it has been recorded from N o r t h and S o u t h A m e r i c a from the same age range.  Angulaiiceras spezianum (CANAVARI, 1882) PI. 3, F i g . 5  *  1882 Aegoceras Spezianum n . sp. - CANAVARI, p . 167, p i . 18, fig. 12a-c 1889 Schlotheimia Speziana CANAVARI - H Y A T T , p. 136  M A T E R I A L - O n e flattened i n t e r n a l m o u l d of mediocre preservation i n shale.  MEASUREMENTS SPECIMEN NO. 724D/1  DMAX  UD  U  WH  18.1  5.0  27.6  9.1  PRHW 13  URHW  VURR  26  2.0  D E S C R I P T I O N - S m a l l , moderately involute f o r m w i t h r a p i d l y enlarging whorls a n d narrow u m b i l i c u s . A s far as preservation allows observation u m b i l i c a l w a l l l o w , u m b i l i c a l shoulder rounded, a n d flanks convex. Dense, sharp, straight, a n d gently prorsiradiate ribs appear to originate on u m b i l i c a l w a l l and terminate ventrally i n incipient nodes. B i f u r c a t i o n occurs near the u m b i l i c a l shoulder, alternation of simple, bifurcating and intercalatory ribs somewhat irregular.  D I S C U S S I O N - T h i s specimen is i n remarkable agreement w i t h the original of CANAVARI (1882). W i t h i n the group of Angulaiiceras occurring i n the U p p e r S i n e m u r i a n A. spezianum is distinguished from A. geyeri (HYATT, 1889; the original of w h i c h is "Schlotheimia lacunaia" i n GEYER, 1886, p. 259, p i . 3, fig. 2223) m a i n l y b y its straight ribs; from A. angustisulcaium  fGEYER, 1886) a n d the very similar A.  dumortieri  (FUCINI, 1903) also b y its less numerous ribs; whereas A. ventricosum has slightly coarser a n d more sigmoid  SYSTEMATIC  SCHL  PALEONTOLOGY  O THEIMIID A E  88  r i b b i n g . In a d d i t i o n , the incipient nodes at the v e n t r a l t e r m i n a t i o n of ribs is another characteristic feature of A.  spezianum.  O C C U R R E N C E - T a s u S o u n d area, Section P , Level 4; from the A r n o u l d i Zone.  DISTRIBUTION  - P r e v i o u s l y this species has only been described from L a Spezia, N o r t h e r n A p p e n i n e s ,  Italy, p r o b a b l y from the U p p e r S i n e m u r i a n .  Angulaiiceras  cf. ventricosum  ( S O W E R B Y , 1831)  PI. 3, F i g . 9  cf. pars cf. cf. pars non cf. cf. non cf. cf. cf.  1856 Ammonites Moreanus d ' O R B . - H A U E R , p . , p i . 15, fig. 3-4 (non fig. 1-2) 1882 Aegoceras ventricosum SOW. sp. - C A N A V A R I , p. 165, p i . 18, fig. 10-11 1886 Aegoceras ventricosum S O W . ( C A N A V . ) - W A H N E R , p. 186, p i . 23, fig. 4-7, 9, 12 (non fig. 8, 10, 11) 1963 Angulaiiceras ventricosum (SOW.) - B L I N D , p. 81, p i . 1, fig. 17 ( = S c h l o t h e i m i a sp. indet. ( B L O O S , 1979, p . 147, p i . 1, fig. 9)) .1976 Sulciferites ventricosus (SOW. 1833) - S C H L E G E L M I L C H , p . 37, p i . 7, fig. 6 1979 Angulaiiceras ventricosum ( S O W E R B Y 1831) - B L O O S , p. 145, p i . 1, fig. 1-8 1981 Angulaiiceras cf. ventricosum (SOW.) - H l L L E B R A N D T , p.504, p i . 2, fig. 2 ( = Sulciferites cf. trapezoidalis) 1985 Angulaiiceras cf. ventricosum ( S O W E R B Y 1831) - P R I N Z , p. 173, p i . 2, fig. 9 1987 Angulaiiceras ventricosum ( S O W E R B Y ) - QUINZIO SINN, p i . 3, fig. 6 1987 Angulaiiceras cf. ventricosum ( S O W E R B Y ) - QUINZIO SINN, p i . 3, fig. 5  M A T E R I A L - T h r e e rather poorly preserved flattened i n t e r n a l moulds i n shale.  MEASUREMENTS SPECIMEN NO. 6101 606C/1 705H/1  DMAX  UD  U  WH  28.1 16.7  5.0 2.8  15.2 10.0  %34  8.4  17.8 16.8 %24  16.3  PRHW  URHW  VURR  wlO,  %18 %20  1.8 2.20  -  -  -  SYSTEMATIC  SCHL  PALEONTOLOGY  O  89  THEIMIIDAE  D E S C R I P T I O N - Involute shell of s m a l l size w i t h r a p i d l y enlarging whorls. U m b i l i c u s narrow w i t h rounded shoulder. N o information regarding the w h o r l section and v e n t r a l features can be deduced due to the bad preservation. Densely r i b b e d , ribs sharp, slightly sigmoid, gently prorsiradiate. B i f u r c a t i o n and intercalation of ribs c o m m o n apparently  w i t h o u t consistent  p a t t e r n . B i f u r c a t i o n occurs at  various points from  the  u m b i l i c a l shoulder to the lower flank. '  D I S C U S S I O N - BLOOS (1979) treated this species in detail refiguring some of WAHNER's (1886) specimens. T h e species displays a certain amount of v a r i a b i l i t y i n r i b b i n g (e.g. shape a n d density of ribs). T h e Q u e e n C h a r l o t t e specimens occupy the straighter and coarser end of the spectrum. T h e y are distinguished from Sulciferites  trapezoidahs  by their narrower u m b i l i c u s and finer sigmoid r i b b i n g .  O C C U R R E N C E - K e n n e c o t t P o i n t , Section A , Level 1; Section D , Level 2; from the Canadensis Zone; K u n g a Island, Section T , Level 6; f r o m the "Coroniceras" Zone.  D I S T R I B U T I O N - In T e t h y a n E u r o p e ( E a s t e r n A l p s , A p p e n i n e s ) from the Rotiforme Zone (sensu WAHNER, 1886), i n northwest  E u r o p e from not lower t h a n the B u c k l a n d i Zone. T h e upper limit of range is not  precisely k n o w n , b u t not higher t h a n O b t u s u m Zone (BLOOS, 1979). A l s o recorded from the B u c k l a n d i and S e m i c o s t a t u m Zone of C h i l e and P e r u (RlCCARDI et al, 1990).  G E N U S Sulciferites  TYPE  S P E C I E S - Ammonites  sulcatus  SPATH, 1922  J . BUCKMAN, 1844 (non  SIMPSON) (=Schlotheimia  sulcifera  B U C K M A N , 1911). F o r details see BLOOS, 1979, p. 150.  S Y N O N Y M Y - Charmasseiceras  SPATH, 1924; Encycloceras  BLIND, 1963; Hongkongites  GRABAU, 1928.  S.  SYSTEMATIC  DESCRIPTION  PALEONTOLOGY  S CHL O THEIMIID  90  A E  - Involute forms, variable i n size. S t r o n g l y r i b b e d , bifurcating a n d  intercalatory  ribs  c o m m o n . V e n t r a l sulcus m a y be present at early g r o w t h stage but disappears on adults. I n t e r r u p t i o n of ribs p r o n o u n c e d on juveniles gradually changing to ribs crossing the venter.  R E M A R K S - T h e status of Sulciferites  and the closely related Angulaiiceras  is p r o b l e m a t i c . Despite the  objections expressed by BLOOS (1979, 1988) the classification of DONOVAN and FORSEY, 1973 is retained here (for further discussion see R e m a r k s under Angulaiiceras). species belonging to Sulciferites  Ironically, w i t h this practice most of the  does not have a characteristic v e n t r a l sulcus to w h i c h their generic name  refers.  AGE  A N D DISTRIBUTION  - Sulciferites  is widely d i s t r i b u t e d i n the uppermost  Hettangian(?)-Lower  S i n e m u r i a n w i t h occurrences i n E u r o p e (both the M e d i t e r r a n e a n and N o r t h w e s t E u r o p e a n province), the H i m a l a y a s , C h i n a , Indonesia, N o r t h and S o u t h A m e r i c a .  Sulciferites  marmoreus  (OPPEL, 1862)  PI. 3, F i g . 8  *  ?  1856 1862 1878 1878 1886 1908 1908 1963 1963  cf. non  1963 Schlotheimia (Angulaiiceras) 1967 Charmasseiceras marmoreum  cf.  1983 Schlotheimia 1984 Schlotheimia 1988 Angulaiiceras  marmorea (OPPEL) - BLOOS, p . 129, fig. 2, 3 marmorea (OPPEL) - BRAGA et al., p. 273, p i . 1, fig. 10-11 marmoreum (OPPEL) - BLOOS, p . 6, p i . 1-3; p i . 4, fig. 7-8; p i . 5-8; p i . 9, fig. 1, text-fig. 3-11  ?  1989 Sulciferites  cf. marmoreum  ?  Ammonmites Charmassei D'ORBIGNY - HAUER, p. 49, p i . 14, fig. 1-3 Ammonmites marmoreus n . sp. - OPPEL, p. 130, footnote Aegoceras tenuicostatum n . sp. - HERBICH, p . 110, p i . 20D, fig. 3a-b Aegoceras Charmassei D'ORBIGNY - HERBICH, p . 110, p i . 20D, fig. 2a-b Aegoceras marmoreum OPP. - WAHNER, p . 180, p i . 22, fig. 1-5 Schlotheimia marmorea OPP. - VADASZ, p . 363 Schlotheimia sp. i n d . aff. marmorea OPPEL - DlENER, p . , p i . 15, fig. 5 Schlotheimia marmorea (OPPEL) - BLIND, p . 80, p i . 2, fig. 5 Schlotheimia (Angulaiiceras) curvata n . sp. - BLIND, p. 82, p i . 1, fig. 23 haryicostata - BLIND, p . 83, p i . 1, fig. 19 (OPPEL) - FREBOLD, p. 27, p i . 3, fig. l a - d , 4a-b,; p i . 4, fig. 1, 2a-  c  (Oppel) - RlCCARDI et a l , p i . 2, fig. 1-2  SYSTEMATIC  PALEONTOLOGY  S CHL O THEIMIIDA  E  91  T Y P E - H o l o t y p e : original of HAUER, 1856, p i . 14, fig. 1-3, deposited in the Geologische  Bundesanstalt,  Vienna.  M A T E R I A L - One specimen, relatively well preserved as flattened internal m o u l d in shale.  MEASUREMENTS SPECIMEN NO. 609E/4  DMAX  UD  U  WH  114.3 %85.7  36.4 23.4 17.6 10.5  31.8 27.3  46.0 %41.7  PRHW  URHW  17 13 11 12  VURR  28 28 26 21  1.65 2.15 2.36 1.75  D E S C R I P T I O N - Large, rather evolute form w i t h moderately enlarging whorls and wide u m b i l i c u s . Strongly r i b b e d ; slightly sigmoid ribs start at u m b i l i c a l shoulder broadening toward the venter. V e n t r a l rib ends accentuated  at early growth stage suggesting that ribs do not cross the venter. R i b b i n g p a t t e r n somewhat  irregular, c o m m o n bifurcating a n d intercalating ribs, height of furcation point and origin of secondary ribs varies from lower to m i d d l e flank.  D I S C U S S I O N - T h e species was the subject of a recent revision (BLOOS, 1988). Its assignment to  Sulciferites  here is based on morphological similarities w i t h the "charmassei"-grouTp (in m u c h the same sense as SPATH's genus Charmasseiceras)  w h i c h was l u m p e d into the genus Sulciferites  by DONOVAN and FORSEY (1973).  O u r specimen is slightly more evolute and more r a p i d l y e x p a n d i n g than the average but otherwise it is close to several figured specimens i n c l u d i n g the holotype. T h e specimen falls well w i t h i n the remarkable v a r i a b i l i t y of this species as illustrated b y BLOOS (1988).  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , L e v e l 20; from the Canadensis Zone.  SYSTEMATIC  DISTRIBUTION Cordillera,  S CHL O THEIMIID A E  PALEONTOLOGY  - In E u r o p e i n b o t h  Transylvania)  from  the  provinces: i n the  Marmoreus  Zone  92  M e d i t e r r a n e a n province ( E a s t e r n  (controversially  lowermost S i n e m u r i a n , see discussion i n C h a p t e r 3) and i n northwest  uppermost  Alps,  Sinemurian  Betic and/or  E u r o p e ( S W G e r m a n y ) from  topmost H e t t a n g i a n ( A n g u l a t a Zone, Depressa Subzone). S. marmoreus,  the  or at least closely related forms,  were recorded from T e t h y a n areas outside E u r o p e (the H i m a l a y a s and R o t t i Island, Indonesia) ( G U E X and T A Y L O R , 1976). A comparable form occurs i n the Canadensis Zone of A r g e n t i n a ( R l C C A R D I et a l . , 1989).  Sulciferites  cf. trapezoidalis  ( S O W E R B Y , 1831)  PI. 3, F i g . 2-3  cf. cf. pars cf. ?  cf. cf. cf. non  MATERIAL  1882 1886 1908 1908 1963 1979 1981 1987  Aegoceras trapezoidale S O W . sp. - C A N A V A R I , p. 165, p i . 18, fig. 8-9 Aegoceras trapezoidale S O W . ( C A N A V . ) - W A H N E R , p. 185, p i . 23, fig. 1-3 (non fig. 4) Schlotheimia trapezoidale S O W . sp. - V A D A S Z , p. 365 Schlotheimia sp. i n d . ex aff. trapezoidalis (SOW.) C A N . - D l E N E R , p. , p i . 15, fig. 2 Schlotheimia (Encycloceras) trapezoidalis (SOW.) - B L I N D , p. 81, p i . 1, fig 21 "Sulciferites" trapezoidalis ( S O W E R B Y 1831) - B L O O S , p. 160, p i . 2, fig. 4 Angulaticeras cf. ventricosum (SOW.) - H l L L E B R A N D T , p.504, p i . 2, fig. 2 Sulciferites cf. trapezoidalis ( S O W E R B Y ) - QUINZIO SINN, p i . 2, fig. 7 (=Sulciferites cf. posttaurinus ( W A H N E R , 1886))  - 9 specimens  of very poor to mediocre preservation,  flattened  impressions i n shale  siltstone..  MEASUREMENTS SPECIMEN NO. 610A/6 605C/1 609D/12  DMAX  UD  U  WH  23.0 29.3 30.8  5.5 6.6 7.0  23.9 27.7 22.7  12.3 12.5 12.4  PRHW 9' 9 11  URHW  VURR  18 17  2.0 1.88  20  1.82  and  SYSTEMATIC  DESCRIPTION prorsiradiate,  S CHL O  PALEONTOLOGY  -  Small,  almost  involute  straight  form  with  narrow  93  THEIMIIDAE  u m b i l i c u s . Strongly  ribbed;  ribs  sharp,  or slightly curved forward. B i f u r c a t i o n of ribs occur near the  gently  umbilical  shoulder, i n t e r c a l a t i n g ribs also present.  DISCUSSION  - T h e studied  specimens  differ  somewhat  from other  figured m a t e r i a l  by h a v i n g  more  c o m m o n l y bifurcating ribs. O t h e r characteristics agree reasonably well. S.  trapezoidalis  differs from the  similarly s m a l l and involute Angulaticeras  ventricosum  straighter and less dense ribs and wider u m b i l i c u s . A n o t h e r related f o r m is S. posttaurinus  by  its  w h i c h can be  distinguished b y its coarser and blunter r i b b i n g .  OCCURRENCE  - K e n n e c o t t P o i n t , Section D , Level 1, 11, 12, 21;, Section F , L e v e l 5 and 20; f r o m the  Canadensis Zone.  DISTRIBUTION  -  S.  trapezoidalis  is k n o w n from the  Mediterranean  A p p e n i n e s , E a s t e r n A l p s , T r a n s s y l v a n i a ) , where available stratigraphic  province  in Europe  information suggests  (Northern Marmoreus  Zone. O u t s i d e E u r o p e a specimen from the C o a s t a l C o r d i l l e r a of C h i l a may be referred to this ("Angulaticeras  cf. ventricosum"  species  of H l L L E B R A N D T , 1981).  Sulciferites  ? sp.  PI. 3, F i g . 6  v. ?  1967 Charmasseiceras  marmoreum  ( O P P E L ) - F R E B O L D , p. 27, p i . 3, fig. l a - d , 4a-b,; p i . 4, fig. 1,  2a-c  v. ?  1985 Boucaulticeras  boucaultianum  ( D ' O R B I G N Y ) - O'BRIEN, p. 32, p i . 5, fig. 4  M A T E R I A L - 5 p o o r l y preserved flattened i n t e r n a l moulds i n shale.  SYSTEMATIC  SCHL  PALEONTOLOGY  O THEIMIID  94  A E  MEASUREMENTS SPECIMEN NO. 704F/7 610D/11  DMAX  UD  U  WH  44.1 53.6  %8.6 %11  %19.5 ss20.5  %23.6 %26.4  URHW  PRHW «14  -  %27 %30  VURR %1.93  --  D E S C R I P T I O N - M e d i u m size, m i d v o l u t e i n d i v i d u a l s w i t h relatively n a r r o w u m b i l i c u s . Densely ribbed w i t h gently prorsiradiate ribs w h i c h slightly curved forward. T h e poor preservation obliterates the r i b b i n g p a t t e r n , but bifurcation frequently occurs on the lower flank. Intercalating ribs less numerous.  D I S C U S S I O N - O u r m a t e r i a l appears to be most closely resembling p a r t i c u l a r l y in r i b b i n g style to the form described as "Charmasseiceras marmoreum"  by FREBOLD, 1967 i n spite of the difference in size. T h e r i b b i n g  density of this form consistently exceeds that of Sulciferites  marmoreus  to such extent that they  are  probably not conspecific. T h e Q u e e n C h a r l o t t e material, i f indeed conspecific w i t h the i n d i v i d u a l s from Tyaughton  Creek  area, m a y  consist  of inner  whorls, or  alternately,  microchonchs,  whereas the  large  i n d i v i d u a l s from the latter locality m a y represent macroconhs as the fading of r i b b i n g suggests. D i m o r p h i s m in schlotheimids was postulated  b y CALLOMON (1981) w i t h special reference to some giant forms. F o r  comparison, Frebold's specimen (pi. 4, fig. 1) has a w h o r l height of 129 m m and an estimated diameter of 360 mm. S. ? sp. is clearly distinguished from Angulaiiceras  boucaultianum  b y its wider u m b i l i c u s and coarser  ribbing.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , L e v e l 21, 23, 24; K u n g a Island, Section S, Level 6; from the Canadensis Zone.  D I S T R I B U T I O N - T h e s y n o n y m i z e d f o r m occurs i n the T y a u g h t o n Creek area (southern B r i t i s h C o l u m b i a ) in the Canadensis Zone.  SYSTEMATIC  S CHL O THEIMIID  PALEONTOLOGY  95  A E  F A M I L Y A R I E T I T I D A E H Y A T T , 1875 S U B F A M I L Y A L S A T I T I N A E S P A T H , 1924 G E N U S Sunrisites  T Y P E S P E C I E S - Sunrisites  DESCRIPTION  sunnsense  G U E X , 1980  G U E X , 1980, by original designation.  - R e l a t i v e l y evolute forms, w h o r l section subrectangular to ellipsoid, wider t h a n h i g h . V e n t e r  bearing no keel. Coarsely r i b b e d w i t h b l u n t , rectiradiate ribs fading out or giving rise to faint secondary ribs before reaching ventro-lateral shoulder.  AGE  A N D DISTRIBUTION  - The  type  species  occures  i n the  Oregonense zones sensu T A Y L O R , i n prep.) of N e v a d a . S. hadroptychus  Upper  Hettangian  (Morganense  to  ( W A E H N E R , 1886), the other species  originally assigned to the genus, was described from the M e g a s t o m a Beds of the A u s t r i a n A l p s ( W A H N E R , 1886) a n d p r o b a b l y also occurs i n the U p p e r H e t t a n g i a n of N e v a d a ( G U E X , 1980).  Sunrisites  ? senililevis  n . sp.  PI. 5, F i g . 5, 9  T Y P E - H o l o t y p e : G S C S p e c i m e n N o . C-143327/c. P a r a t y p e : Specimen 6 1 1 N / 1 .  T Y P E L O C A L I T Y - Castle Pass near T y a u g h t o n Creek, Taseko Lakes area, B r i t i s h C o l u m b i a , G S C locality C-143327. F o r the paratype see Occurrence below.  T Y P E . H O R I Z O N - B a s a l part of Canadensis Zone.  SYSTEMATIC P A L E O N T O L O G Y  ALSA  96  TITINAE  E T Y M O L O G Y - senihlevis (Latin "old smooth") refers to the smooth outer whorl of the holotype.  MATERIAL - 1 poorly preserved external mould from the Queen Charlotte Islands. The holotype is a well preserved, though fragmentary internal mould with some shelly material.  MEASUREMENTS SPECIMEN NO.  DMAX  C143327/C (Holotype)  159  611N/1 (Paratype)  67  UD  U  61.5 41.1  39  31  46.3  WH 59.5  WW  PRHW  58.0 10  22  -  9  DIAGNOSIS - Moderately evolute form of large adult diameter. Whorl section ellipsoid. Inner whorls coarsely ribbed, ribs blunt, rectiradiate. Last whorl becoming smooth.  Figure 6-3  Cross section of the holotype of Sunrisites senihlevis at DMAX=159 mm  SYSTEMATIC  PALEONTOLOGY  ALSA  97  TITINAE  D E S C R I P T I O N - M i d v o l u t e species a t t a i n i n g large size. W h o r l section ellipsoid, whorls slightly compressed at j u v e n i l e stage, later becoming more inflated w i t h nearly equal w i d t h and height ( F i g . 6-3). Largest w i d t h located at lower t h i r d of flank. U m b i l i c a l wall high and steep, u m b i l i c a l shoulder rounded. F l a n k s convex, venter bearing no keel. Coarsely costate up to an u m b i l i c a l diameter of cca. 40 m m , where ribs fade rather a b r u p t l y , last w h o r l s m o o t h . R i b s widely spaced, rectiradiate, b l u n t , h a v i n g a high but  out  rounded  profile. R i b frequency nearly constant at 8-10 ribs per half w h o r l . R i b s strongest at m i d flank, fading out a b r u p t l y at ventro-lateral shoulder w i t h o u t crossing venter.  D I S C U S S I O N - T h e asssignment  of the new species to Sunrisites  is based on its coarse, upright r i b b i n g ,  evolute inner whorls, and non keeled venter. It exceeds i n size, however, every k n o w n representatives of the genus and shows a remarkable tendency to become more involute and lose ornament at m a t u r i t y . These m a y be interpreted as d i m o r p h characters of a macroconch or s i m p l y the holotype m a y represent a rare m a t u r e specimen. T h e new species can be distinguished from 5". sunrisensis less dense costation, and ellipsoid w h o r l section. S. hadroptychus  b y its s u b s t a n t i a l l y larger size, coarser a n d differs m a i n l y by being more  evolute,  r e t a i n i n g costation at comparable large diameters, and showing a tendency of flexuous r i b b i n g .  O C C U R R E N C E - K e n n e c o t t P o i n t , Section F , Level 6; from the lower part of Canadensis Zone.  D I S T R I B U T I O N - T h e only two k n o w n i n d i v i d u a l s are the holotype and the Queen C h a r l o t t e specimen, b o t h from the lower part of the Canadensis Zone from T y a u g h t o n Creek and K e n n e c o t t P o i n t , respectively.  SYSTEMATIC  PALEONTOLOGY  ALSA  TITINAE  98  G E N U S Badouxia GUEX and TAYLOR, 1976  T Y P E S P E C I E S - Psiloceras  canadense  FREBOLD, 1951 by original designation (GUEX and TAYLOR, 1976,  p. 525).  D E S C R I P T I O N - M i d v o l u t e forms w i t h r o u n d e d to ellipsoid w h o r l section. R i b b i n g gently  prorsiradiate,  strong on lower flank and fading but v e n t r a l l y on some species, crossing venter by forming a chevron of weak p r i m a r y or faint secondary ribs on others. Sutures relatively simple.  R E M A R K S - T h e genus was originally considered a s c h l o t h e i m h d (GUEX and TAYLOR, 1976), but later it was  transferred  (GUEX,  to  A l s a t i t i n a e as  1980). Besides the  (FREBOLD, 1967))  B.  species  occidentals  included herein. Psiloceras  an  Alsatites-Sunrisites-Badouxia  o r i g i n a l l y assigned  to the  (FREBOLD, 1967) and B.  evolutionary lineage genus (B. oregonensis  canadensis  recognized  B.  columbiae  (TAYLOR, M S name) are  reissi TlLMANN, 1917 was also proposed to be a Badouxia  but it is more likely to represent a Discamphiceras  and  was  also  (QUINZIO SINN, 1987)  based on its r i b b i n g p a t t e r n ( m a x i m u m strength of ribs at  m i d flank) ( D . TAYLOR, pers. c o m m . , 1991).  A G E A N D D I S T R I B U T I O N - Badouxia  is w i d e l y d i s t r i b u t e d around the Pacific margins w i t h occurrences i n  A l a s k a , B r i t i s h C o l u m b i a , Oregon, N e v a d a , P e r u , C h i l e , and Northeastern S i b e r i a (TAYLOR et al., 1984). Its stratigraphic  position  has  been  controversial,  herein  interpreted  as  uppermost  Hettangian  to  basal  S i n e m u r i a n (see C h a p t e r 3 for details).  Badouxia  canadensis  (FREBOLD, 1951)  PI. 5, Fig. 1-2, 6  * v pars  1951 Psiloceras  canadense  sp. nov. - FREBOLD, p. 3, p i . 4-6; p i . 2, fig. 1; p i . 3, fig. 1 (non  p i . 1, fig. 1-3 = Badouxia  oregonensis)  SYSTEMATIC  PALEONTOLOGY  v  1962 Waehneroceras sp. - CORVALAN, p. 158, p i . 1, fig. 4 1964 Psiloceras canadense F r e b o l d - FREBOLD, p. 6, p i . 1, fig. 1-5 1967 Psiloceras canadense F r e b o l d - FREBOLD, p. 18, p i . 1, fig. 1-3 1981 1981 1985 1987 1989  ALSATITINAE  99  Caloceras canadense FREBOLD - HlLLEBRANDT, p. 503, p i . 1, fig. 5 Badouxia canadensis (FREBOLD) - IMLAY, p. 31, p i . 2, fig. 18-21, 24-28 Psiloceras canadense (FREBOLD) - PRINZ, p. 188, p i . 2, fig. 4 Badouxia cf. canadensis (FREBOLD) - QUINZIO SINN, p i . 1, fig. 11 Badouxia canadensis (Frebold) - RlCCARDI et a l , p i . 2, fig. 3-4  T Y P E - Holotype: Psiloceras  canadense FREBOLD, 1951, p. 3, p i . 1, fig. 4; G S C T y p e N o . 11206.  M A T E R I A L - A large n u m b e r of specimens preserved mostly as flattened impressions or i n t e r n a l moulds w i t h the exception of a few less compressed internal moulds.  M E A S U R E M E N T S - A sample of 20 specimens were measured  from a single bed (Section F , Level 14)  Scatter diagrams of U D vs. D M A X and P R H W vs. U D are given i n F i g . 6-5 and 6-6, respectively.  ALSA TITINAE  SYSTEMATIC P A L E O N T O L O G Y  100  UD ( m m ) 30 -i Badouxia canadensis o  Badouxia columbiae 20 — o • o o »o°  10 —  0  Jo  eP  20  40  60  80  DMAX ( m m ) Badouxia canadensis: n=20 y=0.365x-0.02 r=0.92 Badouxia columbiae: n=18 y=0.361x-0.98 r=0.81  Figure 6-4 Scatter diagram of umbilical diameter (UD) vs. maximum diameter (DMAX) of Badouxia canadensis and Badouxia columbiae, both based on samples 20 of specimens from two localities (Section F, Level 14 and Section F, Level 19, respectively)  DESCRIPTION - Midvolute form of medium size, diameter not exceeding 8 cm. Umbilicus moderately wide, tipically representing 35-40% of diameter. Whorls enlarging moderately rapidly, overlapping 30 to 50% of the preceeding one. Whorl section rounded to ellipsoid. Umbilical wall steep and high, umbilical shoulder well defined but rounded. Flanks slightly convex, venter non keeled. Strong, prorsiradiate ribbing confined to lower and middle flank, fading out on upper flank. A tendency of weakening of ribs at larger size may be noticeable. Rib frequency increasing slightly but steadily with diameter, number of ribs at an umbilical diameter of 20 mm commonly 14-16.  DISCUSSION - The species exhibits considerable variability in volution and ribbing strength. B. oregonensis and B. columbiae seem to be closely related to B. canadensis. The first differs mainly by its more slowly  101  ALSATITINAE  SYSTEMATIC P A L E O N T O L O G Y  PRHW 20  •  • «• ••  • •  I  •  m»om oca WOOD  o o  •  • •  o  o  o  o o  o o  o o  D O  OOI 1  >  •  o o O  o  o  a»  10  5 Badouxia  canadensis  Badouxia columbiae  o i  0  i  i  i  « I  l  l  I  l  10  l  l  l  20  UD  30  (mm)  Badouxia canadensis: n=49 y=0.226x+10.54 r=0.63 Badouxia columbiae: n=31 y=0.338x+11.70 r=0.56  Figure 6-5  Scatter diagram of rib frequency (PRHW) vs. umbilical diameter (UD) of  Badouxia canadensis and Badouxia columbiae. Samples as in Fig. 7-3.  expanding whorls, slightly wider umbilicus, smaller whorl height, less well defined umbilical wall and shoulder as well as less prorsiradiate ribbing whereas the latter can be distinguished by its slightly denser costation (Fig. 7-4) consisting of ribs not fading out on the upper flank but being projected forward instead. Statistical studies supporting the separation of B. canadensis and B. columbiae are presented by O'BRIEN (1985).  OCCURRENCE - Kennecott Point, Sections D, F, G; Kunga Island, Section S; from the Canadensis Zone.  DISTRIBUTION - B. canadensis is characteristic of the Canadensis Zone in North America, which is thought to correlate with the uppermost Hettangian - basal Sinemurian (see Chapter 3 for details). It has only been found in allochtonous terranes, not on the craton. Other occurrences around the Pacific margin  SYSTEMATIC  PALEONTOLOGY  ALSA  TITINAE  102  include P e r u (PRINZ, 1985), C h i l e (HlLLEBRANDT, 1981, QUINZIO SINN, 1987), A r g e n t i n a (RlCCARDI et a l , 1989), a n d Northeast S i b e r i a (REPIN, 1977).  Badouxia  columbiae  (FREBOLD, 1967)  PI. 4, F i g . 3; P I . 5, F i g . 3-4, 8  v v  '  * v pars ?  1951 Schlotheimia 1951 Schlotheimia  (Scamnoceras) cf. S. acuticosta - FREBOLD, p . 6, p i . 4, fig. 1 (?) sp. indet. - FREBOLD, p . 7, p i . 4, fig. 2-4  1967 Psiloceras (Curviceras) columbiae n . sp. - FREBOLD, p . 20, p i . 1, fig. 10; p i . 2, fig. 10; p i . 3, fig. 2; text-fig. 5 (non p i . 2, fig. 1) 1981 Badouxia columbiae (FREBOLD) - IMLAY, p . 31, p i . 2, fig. 22-23  T Y P E - H o l o t y p e : Psiloceras  (Curviceras)  columbiae  FREBOLD, 1967, p . 20, p i . 2, fig. 2; G S C T y p e N o .  19925.  M A T E R I A L - A large n u m b e r of specimens preserved mostly as flattened impressions or i n t e r n a l moulds w i t h the exception of a few less compressed i n t e r n a l moulds.  M E A S U R E M E N T S - 20 specimens were measured from a single bed (section F , level 19) to represent a p o p u l a t i o n . Scatter  diagrams of U D vs. D M A X  and P R H W  vs. U D are given i n F i g . 6-4 a n d 6-5,  respectively.  DESCRIPTION  - M i d v o l u t e form of m e d i u m size. U m b i l i c u s representing 30-40% of diameter. W h o r l s  enlarging moderately r a p i d l y . W h o r l section r o u n d e d at an early stage becoming ellipsoid w i t h  height  exceeding w i d t h at adult stage. U m b i l i c a l w a l l steep, u m b i l i c a l shoulder well defined b u t r o u n d e d . S t r o n g l y costate, ribs prorsiradiate, projected forward near ventro-lateral shoulder. T h e i r trend on venter not seen due to poor preservation. N u m b e r of ribs per half w h o r l at an u m b i l i c a l diameter  of 15 m m is c o m m o n l y 16-18.  SYSTEMATIC  A L SA TI TIN A E  PALEONTOLOGY  D I S C U S S I O N - T h e differences between B. columbiae  OCCURRENCE  and B. canadensis  103  are discussed under B.  canadensis.  - K e n n e c o t t P o i n t , Sections D , F , G ; K u n g a Island, Section S; from the upper part of  Canadensis Zone.  D I S T R I B U T I O N - B.  columbiae  is k n o w n to occur i n the Taseko Lakes area (FREBOLD, 1967), A l a s k a  (IMLAY, 1981) and N e v a d a (TAYLOR, 1986, 1990, i n prep.).  Badouxia  oregonensis  TAYLOR, M S name  PI. 4, F i g . 1-2  v pars  1951 Psiloceras  T Y P E - Badouxia  canadense n . sp. - FREBOLD, p. 3, p i . 1, fig. 1-3 o n l y  oregonensis,  TAYLOR, i n prep., Specimen N o . B 7038/1, deposited i n the  Northwest  M u s e u m of N a t u r a l H i s t o r y , P o r t l a n d .  M A T E R I A L - 6 specimens preserved as impressions or flattened e x t e r n a l / i n t e r n a l moulds i n shale.  MEASUREMENTS SPECIMEN NO. 617E 604A/5 617D/1  DMAX  UD  U  48.8 28.3'  24.0 13.5  49.2 47.7  24.2  11.0  45.5  WH 15.7 7.3 7.1  PRHW 14 13 12  D E S C R I P T I O N - M o d e r a t e l y evolute f o r m of s m a l l to m e d i u m size. U m b i l i c u s relatively wide representing nearly one half of diameter. W h o r l s e x p a n d i n g slowly, e m b r a c i n g about one t h i r d of the preceeding one. W h o r l section rounded, u m b i l i c a l wall i n d i s t i n c t . C o s t a t i o n consisting of gently prorsiradiate ribs strongest  SYSTEMATIC PALEONTOLOGY  ALSATI  TINA  E  104  on the lower two t h i r d of flank and fading out on the upper flank. R i b b i n g frequency increasing little w i t h size.  D I S C U S S I O N - Some of the smaller paratype.s of FREBOLD's B. canadensis interpreted as B. oregonensis  based on the differences listed under B. canadensis.  w i t h the holotype. T h e larger individuals demonstrate that B. oregonensis oregonensis Badouxia  (1951, p i . 1, fig. 1-3) can be O u r specimens agree well  can a t t a i n a diameter of 5 c m . B.  is suggested to represent a t r a n s i t i o n a l form between the closely related genera of Sunrisites  and  (TAYLOR, i n prep.).  O C C U R R E N C E - K e n n e c o t t P o i n t , Sections D and F ; from the basal part of Canadensis Zone.  D I S T R I B U T I O N - T h e holotype is described from the Oregonensis Assemblage of the G r a y l o c k F o r m a t i o n , Oregon (TAYLOR, i n prep.). T h e s y n o n y m i z e d m a t e r i a l is derived from the Canadensis Zone of the Taseko Lakes area (FREBOLD, 1967).  Badouxia  cf. occidentals  (FREBOLD, 1967)  PI. 3, F i g . 7, 10  * v cf.  1967 Psiloceras  occidentale  T Y P E - H o l o t y p e : Psiloceras  n . sp. - FREBOLD, p.19, p i . 1, fig. 4-5  occidentale,  FREBOLD, 1967, p. 19, p i . 1, fig. 4; G S C T y p e N o . 20067.  M A T E R I A L - 4 specimens preserved as flattened i n t e r n a l moulds i n shale.  SYSTEMATIC  PALEONTOLOGY  ALSA  105  TITINAE  MEASUREMENTS SPECIMEN NO.  DMAX  UD  84.5 ~75.5  611G 617E/6  DESCRIPTION  U  29 26.5  WH  34.3 35.0  32.3 27.1  - M o d e r a t e l y involute f o r m of m e d i u m size. U m b i l i c u s representing  nearly one t h i r d of  diameter. W h o r l s enlarging rather r a p i d l y overlapping 50-70%. W h o r l section not k n o w n from our specimens. Inner whorls coarsely r i b b e d up to an u m b i l i c a l diameter  of 15 m m after w h i c h r i b b i n g gradually fades  through a phase where ribs are confined to lower flank. R i b s on inner whorls gently prorsiradiate.  D I S C U S S I O N - T h e holotype shows an entirely smooth last w h o r l a n d the paratypes are ribbed faintly on the first half of last w h o r l . O u r specimens differ i n losing costation t h r o u g h a stage characterized by ribs confined to the lower flank. A l s o r i b b i n g on our i n d i v i d u a l s persists to s l i g h t l y larger u m b i l i c a l diameters and the w h o r l expansion rate is somewhat  higher.  O C C U R R E N C E - K e n n e c o t t P o i n t , Sections D and F; from the Canadensis Zone.  D I S T R I B U T I O N - P r e v i o u s l y B. occidentalis Lakes area  (FREBOLD,  1967) a n d N e v a d a  Badouxia  has only been k n o w n f r o m the Canadensis Zone of the Taseko  (TAYLOR,  1990).  aff. occidentalis PI. 4,  Fig.  (FREBOLD,  1967)  4  M A T E R I A L - One specimen preserved as a flattened i n t e r n a l m o u l d .  M E A S U R E M E N T S - Specimen N o . 6 1 4 C / 1 D M A X = 2 8 . 7  UD=7.8  U=27.1  WH=11.3  SYSTEMATIC  PALEONTOLOGY  DESCRIPTION  - M o d e r a t e l y involute shell of s m a l l size. A l t h o u g h preservation is highly compressed, flanks  appear  to  be flat  our  slightly  ALSATI  convex. Inner  TINA  whorls densely ribbed up  106  E  to an  umbilical  diameter  of  a p p r o x i m a t e l y 4 m m where r i b b i n g disappears a b r u p t l y , last w h o r l entirely smooth.  DISCUSSION  - A l t h o u g h the style of ornament warrants comparison w i t h B. occidentalis,  our specimen has  a slightly narrower u m b i l i c u s and p r o b a b l y different w h o r l section. A l s o the r i b b i n g ends significantly earlier t h a n on the type material. S h o u l d our i n d i v i d u a l represent  a new species the decision must await  discovery of more a n d better preserved material.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section G , uppermost part of the Canadensis Zone.  Badouxia  ? sp.  PI. 4, F i g . 5  v pars  1967 Psiloceras  (Curviceras)  columbiae  n . sp. - FREBOLD, p. 20, p i . 2, fig. 1 only  M A T E R I A L - One flattened i n t e r n a l and 1 flattened external moulds of poor preservation i n shale.  MEASUREMENTS SPECIMEN NO. C-156952  611N/2  FREBOLD,1967 p i . 2, fig. 1  DMAX 151  >200  >150  UD 42 6  U 27.8  63  _  12  94 9 45 9  PRHW  WH  _  10  _  _  _  13  the  SYSTEMATIC  PALEONTOLOGY  ALSATITINAE  107  D E S C R I P T I O N - M o d e r a t e l y i n v o l u t e shell of large size. U m b i l i c u s relatively narrow, representing less than 30% of diameter. W h o r l s e x p a n d i n g r a p i d l y , o v e r l a p p i n g nearly 40% of the preceeding one. W h o r l section not k n o w n due to inferior preservation. Inner whorls s t r o n g l y r i b b e d , ribs gently prorsiradiate. R i b b i n g persists up to an u m b i l i c a l diameter of 8-15 m m where it disappears a b r u p t l y , r e m a i n i n g outer whorls smooth.  D I S C U S S I O N - O u r m a t e r i a l shows a r i b b i n g style s i m i l a r to B. occidentalis  but it is s u b s t a n t i a l l y larger i n  size. A reasonable comparison can be d r a w n w i t h one of the paratypes of B. columbiae  (FREBOLD, 1967, p i .  2, fig. 1) w h i c h , however, possess a suture more c o m p l e x t h a n the holotype and other specimens of that species besides the remarkable difference i n size and o r n a m e n t . It is conceivable that these i n d i v i d u a l s represent a m a c r o c o n c h of a species of Badouxia.  T o establish  a d i m o r p h relationship more and better preserved m a t e r i a l w i t h precise stratigraphic i n f o r m a t i o n is needed.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D and F ; from the Canadensis Zone.  F A M I L Y A R I E T I T I D A E H Y A T T , 1875 S U B F A M I L Y A R I E T I T I N A E HYATT, 1875  R E M A R K S - T h i s subfamily is m a i n l y composed of genera w i t h evolute, widely u m b i l i c a t e shell, strong but simple r i b b i n g and keeled venter w i t h the exception of Tmaegoceras ornament. Arnioceras  w h i c h is distinguished by its lack of  is defined by its s m o o t h nucleus. T h e differentiation between the r e m a i n i n g genera  w i t h i n this l i m i t e d m o r p h o l o g i c a l pool has been a source of controversy. A comparison between the generic classification used b y ARKELL et al. (1957), GUERIN-FRANIATTE (1966), DONOVAN et al. (1981) and BLOOS (1988) reveals the c o n t r a s t i n g views of different authors. F r o m our perspective a further p r o b l e m arises from two-dimensionally preserved m a t e r i a l . A s diagnostic v e n t r a l features furnish the basis for d i s t i n c t i o n between genera and subgenera it is p r a c t i c a l l y impossible to safely conclude on the generic i d e n t i t y of m u c h of our  SYSTEMATIC  PALEONTOLOGY  ARTE  TI TINA  108  E  m a t e r i a l ( G . BLOOS, w r i t t e n comm., 1990). P a r a d o x i c a l l y in some cases it is easier to establish  specific  i d e n t i t y based p r i m a r i l y on characteristics of r i b b i n g and accept other a u t h o r s ' generic assignment. Q u a l i t a t i v e and quantitative assessment of r i b b i n g together w i t h v o l u t i o n provides the best clue for identification but the preservation sets serious l i m i t s on the degree of accuracy.  G E N U S Vermiceras  T Y P E S P E C I E S - Ammonites  REMARKS Paracaloceras  -  Vermiceras  spiratissimus  is used  HYATT, 1889  QUENSTEDT, 1883, subsequent designation by SPATH (1924).  here i n the  sense of DONOVAN a n d  as a subgenus. T h e m a i n difference between Vermiceras  FORSEY  s. str. and Paracaloceras  first possess only a shallow keel flanked b y faint if any sulci whereas Paracaloceras strongly carinate-sulcate venter. Such differences are not easily determinable the name Vermiceras  (1973) who  include  is that the  m a y develop  more  i n most of our m a t e r i a l hence  is used as a convenience whilst acknowledging that Paracaloceras  m a y be present i n  the Q u e e n C h a r l o t t e Islands.  A G E A N D D I S T R I B U T I O N - Vermiceras of B u c k l a n d i Zone i n N o r t h w e s t  s. str. is most c o m m o n i n the C o n y b e a r i and Rotiforme Subzones  E u r o p e . It is also k n o w n from the  (RlCCARDI et a l , 1990). Paracaloceras  is characteristic  several species from the N o r t h e r n A l p s are illustrated  B u c k l a n d i Zone i n S o u t h A m e r i c a  of the M e d i t e r r a n e a n  b y WAHNER (1886, 1888). O t h e r T e t h y a n localities  include the H i m a l a y a s and T i m o r (GUEX and TAYLOR, 1976). Paracaloceras Canadensis Zone of N e v a d a (TAYLOR, 1990).  P r o v i n c e i n E u r o p e where  was recently reported f r o m the  SYSTEMATIC  PALEONTOLOGY  109  A RIE TI TIN A E  Vermiceras  cf. supraspiratum  (WABHNER, 1888)  PI. 6, F i g . 2  cf. cf  1882 Arietites 1888 Arietites  spiratissimus supraspiratus  Q u e n s t . - CANAVARI, p. 177, p i . 20, fig. 2 n . f. - WAHNER, p. 298, p i . 20, fig. 6-9  T Y P E - Syntypes: WAHNER, p i . 20, fig. 6-9.  M A T E R I A L - 3 specimens preserved as one-sided, compressed and somewhat weathered i n t e r n a l moulds.  MEASUREMENTS SPECIMEN NO.  DMAX  604A/4 610H/11  DESCRIPTION  UD  69.5 61.5  U  50.3 41.5  72 67.5  WH 10.2 10.4  PRHW 27 27  - M e d i u m size w i t h extremely wide u m b i l i c u s representing a p p r o x i m a t e l y 70% of diameter.  F l a n k s appear to be convex. M o d e r a t e l y densely r i b b e d , rib frequency increasing steadily. R i b s rectiradiate, slightly concave ad orally.  DISCUSSION  - T h e poor preservation prevents observation of venter and w h o r l section and renders an  unambiguous identification impossible. T h r e e groups w i t h s i m i l a r l y densely r i b b e d serpenticone morphology can be considered: - F r o m the species i l l u s t r a t e d by WAHNER (1886, 1888) V. supraspiratum and density whereas "Arietites  perspiratus"  shows nearly i d e n t i c a l r i b b i n g style  is more densely r i b b e d and "Arietites  proaries"  concave ribs. A m o n g the N e v a d a n forms c u r r e n t l y under s t u d y b y D . TAYLOR, Paracdloceras also close to our forms but more densely r i b b e d .  possess more morganense  is  SYSTEMATIC  PALEONTOLOGY  - A m o n g the specimens of Vermiceras  A RIE  TIT IN A E  110  s. s t r , the r i b b i n g of V. scylla is p r a c t i c a l l y i n d i s t i n g u i s h a b l e from our  form. However, its venter bears only a weak k e e l w h e r e a s our specimens show traces of a more prominent keel. V. spiratissimum  differs i n h a v i n g straighter ribs.  - E v o l u t e a n d densely r i b b e d representatives of Metophioceras  (e.g. M. janus, M. caesar, a n d M.  longidomus)  differ i n h a v i n g flattened flanks and tricarinate-bisulcate venter, characteristics not observed o n the studied specimens.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section D , Level 3 a n d 9, from the base of Canadensis Zone.  DISTRIBUTION  - V. supraspiratum  is k n o w n from the N o r t h e r n A p p e n i n e s , Italy, a n d N o r t h e r n  A u s t r i a . A c c o r d i n g to WAHNER (1888) it is derived from the M e g a s t o m a and M a r m o r e a zones.  Vermiceras  ex gr. coregonense  (SOWERBY, 1831)  PI. 6, F i g . 1,5  M A T E R I A L - M o r e t h a n 50 specimens, the majority preserved as flattened impressions i n shale.  MEASUREMENTS SPECIMEN NO. 611E/12 610J/6 611H/12 609D/9 609H/11 Mean= . Standard deviation=  DMAX  UD  U  WH  78 61.5 53  44 35 32  56.4 56.9 60.3  17.2 12.4 12.5  50 40.5  24.5 20  49 49.4  13 11.4  54.4 4.98  PRHW 26 26 25 25 21  Alps,  SYSTEMATIC  DESCRIPTION  PALEONTOLOGY  A RIE TIT IN A E  111  - E v o l u t e form, diameter does not exceed 10 c m . W h o r l s enlarging moderately slowly,  u m b i l i c u s representing a p p r o x i m a t e l y 50-55% of diameter. F l a n k s appear to be somewhat convex, although flattened preservation prevents observing w h o r l section. Some specimens show trace of a rather prominent keel possibly flanked b y sulci. Densely r i b b e d ; n u m b e r of ribs 16-20 per half w h o r l at 10 m m , 20-25 at 20 m m u m b i l i c a l diameter. R i b s rectiradiate, slightly concave adorally.  D I S C U S S I O N - D u e to the lack of information of v e n t r a l characteristics a n d whorl section a more accurate identification is not possible. T h e group of species to w h i c h comparison is made includes V. (P.) V. (P.) grunowi (HAUER, 1856),  V. (P.) multicostatum  FREBOLD, 1967, and V. (P.) ? cordieri  coregonense, (CANAVARI,  1888). T h e rib frequency of selected specimens along w i t h representatives of the listed t a x a is given on F i g u r e 6-6. T h e rib frequency by itself is inadequate to serve as a basis of d i s t i n c t i o n . FREBOLD's P. differs from  V. (P.)  coregonense  multicostatum  only b y its more densely r i b b e d innermost whorls, their rib frequency  converges at larger diameter. Some of the Q u e e n C h a r l o t t e specimens fall very close to V. (P.)  multicostatum.  SYSTEMATIC PALEONTOLOGY  A RIE TIT IN A E  112  PRHW 30 -  20 -  10 -  30  20  10  UD  40  (mm)  V. (P.) ex gr. coregonense Queen Charlotte specimens  V. (P.) coregonense Neotype  V. (P.) coregonense Selected specimens. Wanner 1888  V. (P.) grunowi Holotype  V. (P.) cordieri Wanner 1888, pi. 18, fig.4  V. (P.) multicostatum Holotype  V. ex gr. coregonense: n=17 y=0.35x+13.12 r=0.85  Figure 6-6 Rib frequency curves of 7 specimens of Vermiceras ex gr. coregonense from Kennecott Point plotted together with selected type specimens of closely allied species.  OCCURRENCE - Kennecott Point, various levels in Sections D, F, and G; Kunga Island, Section S; from the lower and middle part of the Canadensis Zone.  DISTRIBUTION - V. (P.) coregonense, V. (P.) ? cordieri, and V. (P.) grunowi are recorded from the Marmoreum Zone of the Mediterranean Province in Europe. V. (P.) grunowi is also known from Nevada (TAYLOR, 1990). V. (P.) coregonense or closely related forms occur in the Himalayas (DlENER, 1908) and Timor (ROTHPLETZ, 1892, KRUMBECK, 1923). V. (P.) multicostatum is reported from the Canadensis Zone of the Taseko Lakes area (FREBOLD, 1967).  SYSTEMATIC  PALEONTOLOGY  A RIE  Vermiceras  TIT IN A E  113  sp.  PI. 5, F i g . 7; P I . 6, F i g . 4, 8  M A T E R I A L - M o r e t h a n 20 specimens preserved i n shale or i n concretions i n shale, inner whorls often w i t h considerable relief while outer whorls of larger specimens entirely flattened.  MEASUREMENTS SPECIMEN NO. C-156980/15 C-156980/13 C-156980/16 C-156980/14 C-156980/11  DMAX  UD  U  140  85  90 80 51 35  44  60.1 48.9  46 22.5 19  57.5 43.5 54.3  Mean= Standard deviation=  DESCRIPTION  PRHW  WH 28 21 18.2 16.3 8  25 27 19 22 19  52.86 6.69  - E v o l u t e f o r m of m e d i u m size seldom exceeding 10 c m i n diameter. W h o r l expansion rate  and w h o r l overlap variable, but generally evolute and widely umbilicate. Inner w h o r l preserving considerable relief suggesting r o u n d e d u m b i l i c a l wall, convex flanks a n d p r o b a b l y inflated w h o r l section. In one u n u s u a l l y embedded specimen of m e d i u m size, the venter bearing a b l u n t keel flanked by shallow sulci can be seen (PI. 6, F i g . 4). O r n a m e n t consisting of dense, strong ribs of broad, rounded profile. R i b s straight, prorsiradiate on innermost  whorls, soon b e c o m i n g rectiradiate  and  loosing strength  at  adult  stage. R i b b i n g  frequency  increasing steadily up to an u m b i l i c a l diameter of a p p r o x i m a t e l y 30 m m , remaining nearly constant later ( F i g . 6-7).  ARIETITINAE  SYSTEMATIC P A L E O N T O L O G Y  114  PRHW  1  0  1"  "-1  1  —  20  i  —  i  —  i  —,—  —  40  UD Vermiceras sp.: n=24  n  —  i  i  i  60  i  80  i  .  .  100  (mm) y=0.21x+13.48  r=0.48  Figure 6-7 Rib frequency diagram of six specimens of Canadensis Zone of Kennecott Point.  Vermiceras sp. from the  DISCUSSION - This form resembles species of Vermiceras (Paracaloceras) known from the Alps (e.g. V. coregonense group) but differs from them by its characteristic ribbing style and density curve as shown on Fig. 6-7.  OCCURRENCE - Kennecott Point, Section D, Levels 26-27; Section B, Levels 2 and 4; from the top of Canadensis Zone.  GENUS Metophioceras  SPATH, 1924  T Y P E SPECIES - Ammonites conybeari SOWERBY, 1816, by original designation.  SYSTEMATIC PALEONTOLOGY  A RIE TITINA  E  115  D E S C R I P T I O N - Serpenticone forms of m e d i u m to large size. V e n t e r tricarinate-bisulcate, costation dense. V e n t r a l rib ends m a y bear weak tubercles on inner whorls only.  R E M A R K S - Metophioceras  is used here i n the sense of GUERIN-FRANIATTE (1966) that is for forms w i t h  strongly tricarinate-bisulcate venters similar to Coroniceras  but w i t h o u t persistent tubercles. BLOOS (1989)  pointed out the need for revision of genus as possibly c o n t a i n i n g species of heterogenous origin.  A G E A N D D I S T R I B U T I O N - Metophioceras  is most abundant i n the C o n y b e a r i Subzone at the base of  S i n e m u r i a n . It is best represented i n N o r t h w e s t E u r o p e but also occurs i n N o r t h A m e r i c a (see under rursicostatum).  Metophioceras  cf. rursicostatum  (FREBOLD, 1967)  PI. 7, Fig. 1  * v cf. cf. ?  1967 Paracaloceras rursicostatum n . sp. - FREBOLD, 1967, p. 26, p i . 7, fig. 1-2; p i . 9, fig. 1 1981 Paracaloceras rursicostatum F r e b o l d - IMLAY, p . 33, p i . 6, fig. 1-11 1989 Vermiceras (Paracaloceras) cf. rursicostatum F r e b . - RlCCARDI et al., p i . 2, fig. 6  T Y P E - H o l o t y p e : FREBOLD, 1967, p i . 7, fig. 1 a n d p i . 9, fig. 1, G S C T y p e N o . 19944.  M A T E R I A L - 8 specimens preserved as highly compressed i n t e r n a l moulds i n shale.  M.  SYSTEMATIC  PALEONTOLOGY  A RIE  TIT IN A E  116  MEASUREMENTS SPECIMEN NO.  DMAX  C-156953/1  136  C-156953/2 611L/2  67 60  DESCRIPTION  UD 84 39 35  U  WH  PRHW  61.8  27  58.2 58.3  15.5 13  25 23 22  - E v o l u t e f o r m a t t a i n i n g large size (diameter of 30 c m ) . W h o r l s enlarging slowly, u m b i l i c u s  very wide up to more t h a n 60%. F l a n k s appear to be slightly convex. V e n t e r tricarinate-bisulcate at large size. Densely r i b b e d throughout, rib frequency increasing slowly but steadily ( F i g . 6-8). R i b s of moderately high and rounded profile, rursiradiate to various degree, gently concave adorally.  DISCUSSION  - The  costation of the  species  is variable a n d  changes  rursiradiate r i b b i n g clearly seen on the holotype is less apparent  with  ontogeny.  The  diagnostic  on the paratype and at smaller sizes.  S i m i l a r l y , the largest i n d i v i d u a l s i n our collection are i n good agreement w i t h the holotype whereas the more completely preserved smaller ones are closer to the paratype a n d also resemble similar sized specimens of V. ex gr.  coregonense.  SYSTEMATIC P A L E O N T O L O G Y  A RIE TITIN A E  117  PRHW -  ^-—  -  20  .L^C~  QCI s p e c i m e n s 1  5  Holotype  Paratype A  1 —I I  1  10  20  1  1  50  UD  100  200  (mm)  n=24 y=0.124x+17.17 r=0.79  Figure 6-8 Rib frequency curves of 5 specimens of Metophioceras cf. rursicostatum. from Kennecott Point plotted together with the holotype and paratype.  OCCURRENCE - Kennecott Point, Sections D and F; from the Canadensis Zone.  A G E AND DISTRIBUTION  - At the type locality in Taseko Lakes area M. rursicostatum occurs in the  Canadensis Zone (FREBOLD, 1967). In Alaska it also cooccurs with Badouxia canadensis (IMLAY, 1981). In Nevada the species ranges higher than B. canadensis (TAYLOR, 1990). The only record from outside North America is a possible occurrence from the Canadensis Zone of Argentina (RlCCARDI et al., 1989).  SYSTEMATIC  118  A RIE TIT IN A E  PALEONTOLOGY  Metophioceras  aff. rotarium  (BUCKMAN, 1925)  PI. 6, Fig. 3, 6  aff. * aff.  1925 Diploselhtes rotanus nov. - BUCKMAN, pi. 171 1966 Coroniceras (Metophioceras) rotarium (S. S. BUCKMAN, 1925) - GUERIN-FRANIATTE, p. 179, pi. 66-67, text-fig. 66-67 (with synonymy)  M A T E R I A L - 8 specimens preserved as flattened one-sided internal moulds in shale.  MEASUREMENTS SPECIMEN NO. 607E/1 623A/1 606A/1 C156980/31  DMAX 105.5 >100 38.5 38  UD 71.5 67.5 21.5 22  U  WH  67.8  17.5  56.8 58  9.0 8.7  PRHW 26 23 18 18  D E S C R I P T I O N - H i g h l y evolute form w i t h m a x i m u m diameter exceeding 10 c m . W h o r l overlap less t h a n 10%, u m b i l i c u s wide, w h o r l enlarging slowly. Traces of pronounced v e n t r a l keel flanked b y sulci a n d possibly carinae seen despite flattened preservation. Densely ribbed, r i b b i n g frequency increasing steadily. N u m b e r of ribs 20 to 25 at 50 m m u m b i l i c a l diameter ( F i g . 6-9). R i b s strong, h i g h , rectiradiate b u t concave adorally. V e n t r a l r i b ends bearing weak tubercles on inner whorls only, later d i m i n i s h i n g to slightly swollen r i b terminations.  SYSTEMATIC P A L E O N T O L O G Y  A RIE TI TIN A E  119  PRHW 30  20 —  10  0  -  1  1  0  1  1  1  1  1  1  1  1  25  1  1  1  1  1  50  UD  75  (mm)  n=23 y=0.203x+11.61 r=0.B6  Figure 6-9 Rib frequency curves of 7 specimens of Metophioceras aff. rotanum from Kennecott Point plotted together with the holotype and another representative specimen of the species.  DISCUSSION - The assignment of this form to Metophioceras is based on the weak tubercles developed on innermost whorls only. The closest comparison can be made with M. rotanum which is quite similar in ribbing but differs in having an even slower expansion rate therefore less high outer whorl and wider umbilicus. It differs from M. rursicostatum by having less rursiradiate and more concave ribbing.  OCCURRENCE - Kennecott Point, Sections A, B, and D; from the upper part of the Canadensis Zone and "Coroniceras" Zone.  SYSTEMATIC  PALEONTOLOGY  D I S T R I B U T I O N - M. rotarium  A RIE  TIT IN A E  120  is k n o w n from the C o n y b e a r i Subzone ( B u c k l a n d i Zone) o f B r i t a i n a n d  France.  Metophioceras  spp.  PI. 7, F i g . 4  M A T E R I A L - A p p r o x i m a t e l y 15 specimens, generally poorly preserved as flattened i n t e r n a l moulds i n shale.  D I S C U S S I O N - T h e specimens grouped under Metophioceras  spp. display evolute shell, i n d i c a t i o n of stout  whorls, dense, upright r i b b i n g a n d traces of tricarinate-bisulcate venter. T h e i r specific i d e n t i t y could not have been established due to poor preservation.  O C C U R R E N C E - K e n n e c o t t P o i n t , various levels i n sections A , B , D , a n d F , from the upper part of the Canadensis Zone a n d "Coroniceras" Zone.  G E N U S Coroniceras  T Y P E S P E C I E S - Ammonites  AGE  A N D DISTRIBUTION  Kridion  H Y A T T , 1867  ZlETEN, 1830, subsequent designation b y BONARELLI (1900).  - Coroniceras  is a c o s m o p o l i t a n genus occuring i n the B u c k l a n d i a n d  S e m i c o s t a t u m zones (Rotiforme through L y r a subzones).  Coroniceras  ? spp.  P L 6, F i g . 7  M A T E R I A L - 14 poorly preserved specimens, most of t h e m flattened impressions i n shale.  SYSTEMATIC  PALEONTOLOGY  A RIE TIT IN A E  121  D I S C U S S I O N - Included here are evolute forms of various size w i t h relatively r a p i d l y enlarging whorls and strong, dense r i b b i n g . T h e expansion rate is higher t h a n i n Metophioceras row of tubercles t y p i c a l of Coroniceras  or Vermiceras.  T h e ventro-lateral  is o n l y vaguely seen on some less weathered specimens.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section B ; K u n g a Island, Section T , Levels 2-9, from the " C o r o n i c e r a s " Zone.  A r i e t i t i n a e gen. et sp. indet. PI. 7, F i g . 6  M A T E R I A L - 6 flattened w h o r l fragments of very large size preserved i n shale and siltstone.  M E A S U R E M E N T S - Specimen N o . 6 0 7 B / 1 W H 97; Specimen N o . 6 1 1 E / 1 6 W H 77  D E S C R I P T I O N - F r a g m e n t s no more t h a n VlO of a w h o r l . W h o r l height approaching 10 c m , curvature suggesting  giant  diameter  i n the  order  of a p p r o x i m a t e l y 80 c m . V e n t e r strongly  tricarinate-bisulcate.  C o s t a t i o n moderately dense, somewhat irregular, some ribs apparently bifurcating at origin at u m b i l i c a l end. R i b s b l u n t , low, adorally s l i g h t l y concave, fading out before reaching v e n t r a l carina.  D I S C U S S I O N - T h e w h o r l fragments, as their giant size and irregular r i b b i n g suggest, belong to mature or senile i n d i v i d u a l s . In the lack of corresponding inner whorls no generic identification can be made.  O C C U R R E N C E - K e n n e c o t t P o i n t , Sections B , D , and F ; from the upper part of the Canadensis Zone and " C o r o n i c e r a s " Zone.  SYSTEMATIC  PALEONTOLOGY  A RIE  G E N U S Arnioceras  T Y P E S P E C I E S - Arnioceras  cuneiforme  TI TINA  E  122  HYATT, 1867  HYATT, 1867, by subsequent designation (ARKELL, 1951, p. 217,  I C Z N O p i n i o n 307).  SYNONYMY  - Arnioceras  LOPEZ, 1967; Eparnioceras  SPATH, 1919 nomen  nullum;  Arniotites  WHITEAVES 1889;  Burckhardticeras  SPATH, 1924.  D E S C R I P T I O N - E v o l u t e forms w i t h wide u m b i l i c u s representing about 45-60% of diameter. W h o r l section subrectangular  to oval. V e n t e r bearing a sharp keel flanked by sulci i n most cases; some forms possess  tricarinate venter. Innermost whorls diagnostically smooth up to various diameters. After the smooth stage simple r i b b i n g develops consisting of gently prorsiradiate to gently rursiradiate, sharp, acute, most straight ribs. R i b s may be projected forward before their v e n t r a l t e r m i n a t i o n w h i c h sometimes  often  accentuated.  Sutures relatively simple characterized by deeply incised lateral lobes.  R E M A R K S - Arnioceras  as a genus is easy to identify whereas the recognition of species is a difficult task.  T h e plethora of n o m i n a l species (their n u m b e r exceeds 50) often display only m i n o r differences. F r o m a single locality i n Italy FUCINI (1902) distinguished 29 species, 18 of w h i c h were new, and numerous subspecies. T h e narrow species concept employed by h i m has been a t r a d i t i o n concerning Arnioceras:  Diagnostic features  used to separate species include the u m b i l i c a l ratio ( U ) , u m b i l i c a l diameter at w h i c h ribs appear, trend of ribs, rib density pattern, and ventral t e r m i n a t i o n of ribs. Since the flattened  preservation of the  Queen  C h a r l o t t e m a t e r i a l precludes the observation of i m p o r t a n t features such as the w h o r l section and venter, the use of ex gr. n o m e n c l a t u r a l category is sometimes  A G E A N D D I S T R I B U T I O N - Arnioceras  necessary.  is a cosmopolitan genus w i t h a relatively long range. It is k n o w n  from p r a c t i c a l l y every region where ammonitiferous L o w e r S i n e m u r i a n is exposed. In E u r o p e it is diverse and  A RIE TIT IN A E  SYSTEMATIC PALEONTOLOGY  123  abundant in both provinces. It is also well known from the Circum-Pacific (see SATO, 1957 and 1975 for west and southwest Pacific, RlCCARDI et al., 1990 for South American, FREBOLD and TIPPER, 1970 for Canadian, IMLAY, 1981 for Alaskan, HALLAM, 1965 for other western North American occurrences).  Arnioceras  appeared near the end of the Bucklandi Zone and ranged through the Obtusum Zone (DEAN et al., 1961, MOUTERDE et al., 1971), however, it is most characteristic to the Semicostatum Zone. The  succession of the species has been the subject of relatively few studies (e. g. SPATH, 1956;  BLIND, 1963, CASSINIS and CANTALUPPI, 1967, BRAGA et a l , 1984b) possibly due to the problems of interpretation of some closely related and narrowly defined species.  Arnioceras  arnouldi  (DUMORTIER, 1867)  PI. 8, Fig. 3; PI. 9, Fig. 1-2  1867 Ammonites  arnouldi  Nov. Sp. - DUMORTIER, p. 27, pi. 5, fig. 1-2; pi. 6, fig. 1-6  1869 Ammonites nevadanus, Gabb - GABB, p. 6, pi. 3, fig. 1 1878 Arietites Douvillei BAYLE - BAYLE, pi. 76, fig. 2-3 pars ?  1902 Arnioceras 1928 Arnioceras  Arnouldi DUM. - FUCINI, p. 193, pi. 25, fig. 1-2 (non fig. 3 = Arnioceras kwakiutlanus sp. nov. - CRICKMAY, p.  1956 Arnioceras 1966 Arnioceras 1967 Arnioceras  arnouldi (DUM.) - ERBEN, p. 272, pi. 32, fig. 1 arnouldi (DUMORTIER, 1867) - GUERIN-FRANIATTE, p. 279, pi. 150-152 arnouldi (DUM.) - CANTALUPPI, p. 60, pi. 7, fig. 2-3  1979 Arnioceras  cf. arnouldi  1981 Arnioceras  arnouldi (DUMORTIER, 1867) - SMITH, p. 135, pi. 1, fig. 3-5, text-fig. 6-2  T Y P E - Lectotype: "Ammonites  (DUM.) - GEYER, p. 208, fig. 5d ( = Epophioceras  Arnouldi"  densicosta)  sp.)  of DUMORTIER, 1867, pi. 6, fig. 1-4, designated and refigured by  GUERIN-FRANIATTE, 1966, p. 279, pi. 150; deposited in the Natural History Museum of Lyon.  M A T E R I A L - 15 specimens, 2 of them almost complete compressed internal moulds, 1 three-dimensional whorl fragment, impressions.  1 almost complete impression, while the others are incomplete and poorly preserved  SYSTEMATIC P A L E O N T O L O G Y  A RIE TI TIN A E  124  PRWH  40 -.  0  ' 0  1  1  1  1  1  1  1  1  50  1  1  1  100  UD  1  150  (mm)  n=27 y=0.172x+15.19 r=0.78 Figure 6-10  Rib density curves of Arnioceras arnouldi.  MEASUREMENTS SPECIMEN NO. 717A/1 708C/1 ST90-06/1  DMAX  UD  U  WH  PRHW  %225 ssl25 ssllO  153 «87 70  %68 %69 64  38 26 28  40 «30 27  DESCRIPTION - Evolute form attaining large size. Whorl section subrectangular, venter bearing a sharp, high keel flanked by well-developed sulci. Umbilicus represents 60-70% of diameter. Nucleus smooth up to an umbilical diameter of 5-9 mm from which point dense ribbing develops. Ribs sharp and high, rectiradiate and straight on juvenile becoming rursiradiate and concave adorally on adults, projected forward at the ventrolateral shoulder. Rib density increases throughout ontogeny (Fig. 6-10).  SYSTEMATIC  PALEONTOLOGY  D I S C U S S I O N - Arnioceras  arnouldi  A RIE TIT IN A E  125  is p r o b a b l y the largest species w i t h the widest u m b i l i c u s among the  representatives of the genus. T h e rib density of some of our i n d i v i d u a l s exceed the upper limit of rib density range d e t e r m i n e d by GUERIN-FRANIATTE (1966, fig. 142).A. speciosum, be distinguished by its straight rursiradiate Arniotites  rectiradiate  w i t h m a t u r i t y . GABB's (1867) A.  kwakiutlanus  r i b b i n g not nevadanus  w h i c h can also a t t a i n large size, can  showing a tendency  to become  is tentatively s y n o n y m i z e d w i t h  arcuate A.  and  arnouldi.  CRICKMAY, 1928 is based on rather incomplete and poorly preserved type material  and is uninterpretable. It is most likely to represent fragments of A. arnouldi  although it cannot be stated  decisively an the name should be allowed to fall into disuse.  O C C U R R E N C E - Y a k o u n R i v e r , Section H; T a s u S o u n d , Section Q; K u n g a Island, Section  S and T ; from  the A r n o u l d i a n d V a r i a n s Zones.  A G E A N D D I S T R I B U T I O N - A. arnouldi  is k n o w n i n E u r o p e from the upper B u c k l a n d i t h r o u g h O b t u s u m  zones (CASSINIS and CANTALUPPI, 1967). T h e species has also been recorded from M e x i c o (ERBEN, 1956) and N e v a d a (SMITH, 1981) from the  " U n i t w i t h Arnioceras  geometncoides"  and A.  ceratitoides  respectively.  Arnioceras  miserabile  (QUENSTEDT, 1858)  PI. 7, F i g . 2  1858 1879 1884 1886 1889 1902 1955 1956 1966 1973 1976  Ammonites miserabilis - QUENSTEDT, p. 71, p i . 8, fig. 7 Ammonites geometricus var. Hartmanni OPPEL - REYNES, p i . 15, fig. 3-4 Ammonites miserabilis - QUENSTEDT, p. 106, p i . 13, fig. 27-29 Arietites ambiguus nov. sp. - GEYER, p. 252, p i . 3, fig. 11-12 Arnioceras miserabilis var. acutidorsale - HYATT, p. 162, p i . 2, fig. 4-6 Arnioceras miserabile Q U . - FUCINI, p. 162, p i . 16, fig. 10 Arnioceras miserabile (QU.) - DONOVAN, p. 28 Arnioceras cf. miserabile (QU.) - ERBEN, p. 273, p i . 37, fig. 18 Arnioceras miserabile (QUENSTEDT, 1858) - GUERIN-FRANIATTE, p. 254, p i . 136, fig. 1-4 Arnioceras cf. miserabile (QU.) - GEYER, p. 52, p i . 4, fig. 6 Arnioceras miserabile (QU.) - SCHLEGELMILCH, p. 49, p i . 21, fig. fig. 5  Zone,  SYSTEMATIC  pars  PALEONTOLOGY  1981 Arnioceras 1985 Arnioceras 1987 Arnioceras  A RIE  TIT IN A E  126  miserabile (QUENSTEDT, 1858) - SMITH, p. 143, p i . 2, fig. 2 (non fig. 3 Hypasteroceras? sp. cf. miserabile (QUENSTEDT, 1858) - PRINZ, p. 179, p i . 3, fig. 6 cf. miserabile (QUENSTEDT) - QUINZIO SINN, p i . 3, fig. 2  T Y P E - Neotype: "Ammonites  miserabilis"  of QUENSTEDT, 1884, p i . 13, fig. 27, designated and refigured by  GUERIN-FRANIATTE, 1966, p. 254, p i . 136, fig. 1.  M A T E R I A L - Three specimens preserved as impressions i n shale.  MEASUREMENTS SPECIMEN NO.  DMAX  2A/1 705P/3  34.3 20.8  UD 18.7 9.9  U 54.5 47.6  WH 8.7 5.2  D E S C R I P T I O N - E v o l u t e f o r m w i t h wide u m b i l i c u s a n d slowly enlarging whorls. T h e smaller i n d i v i d u a l entirely smooth, on the larger one faint, gently arcuate incipient ribs appear only at an u m b i l i c a l diameter of 18 m m .  D I S C U S S I O N - A. miserabile  can be readily distinguished f r o m other species of Arnioceras  b y its smooth  shell displaying only faint lirae or incipient r i b b i n g from an u m b i l i c a l diameter over 1 c m . Therefore it can be safely identified on our two-dimensionally preserved m a t e r i a l , even though the diagnostic ovate-ogival w h o r l section and poorly developed or l a c k i n g keel cannot be observed.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 12; K u n g a Island, Section T ; Level 14; from the A r n o u l d i Zone.  SYSTEMATIC  PALEONTOLOGY  D I S T R I B U T I O N - In E u r o p e A. miserabile provinces.  It  has  also  been  127  A RIE TI TIN A E  reported  occurs i n both the northwest  from  several  localities  in  European and Mediterranean  South  America  (Colombia,  Peru,  Chile)(RJCCARDI et al, 1990) as well as N o r t h A m e r i c a (Nevada: SMITH, 1981, M e x i c o : ERBEN, 1956). W h e r e detailed stratigraphic information is available it suggests S e m i c o s t a t u m Zone age.  Arnioceras  cf. densicosta  (QUENSTEDT, 1884)  PI. 7, Fig. 3  cf. *cf. cf.  1879 Ammonites 1884 Ammonites 1902 Arnioceras 1955 Arnioceras 1966 Arnioceras 1981 Arnioceras 1985 Arnioceras 1987 Arnioceras  cf.  geometricus OPPEL - REYNES, p i . 14, fig. 5-6 falcaries densicosta - QUENSTEDT, p. 100, p i . 13, fig. 7 pluriplicatum n . sp. - FUCINI, p . 155, p i . 25, fig. 4-5 cf. densicosta (QUENSTEDT) - DONOVAN, p. 27 cf. densicosta (QUENSTEDT, 1884) - GUERIN-FRANIATTE, p. 265, p i . 142, fig. 1-3, text-fig. 130-131 cf. A. densicosta (QUENSTEDT) - IMLAY, p. 33, p i . 5, fig. 9-11, 16-24 pluriplicatum FUCINI - BRAGA et a l , p . 96, p i . 1, fig. 3 cf. densicosta (QUENSTEDT) - QUINZIO SINN, p i . 2, fig. 14  T Y P E - Lectotype: "Ammonites  falcaries  densicosta"  of QUENSTEDT, 1884, p i . 13, fig. 7, designated a n d  refigured b y GUERIN-FRANIATTE, 1966, p . 265, p i . 142, fig. 1; deposited i n the Quenstedt collection of the Geological Institute, T u b i n g e n .  M A T E R I A L - One flattened i n t e r n a l a n d external m o u l d preserved i n shale.  MEASUREMENTS SPECIMEN NO. K6E/1  DMAX 42.8  UD 21.2  U 49.5  WH 11.0  PRHW 25  D E S C R I P T I O N - E v o l u t e form w i t h wide u m b i l i c u s and moderately enlarging whorls. S m o o t h up to an u m b i l i c a l diameter  of 7 m m , where  dense, r a d i a l r i b b i n g develops.  Later ribs tend  to become  gently  SYSTEMATIC PALEONTOLOGY  A RIE  TITINA  E  128  rursiradiate. R i b b i n g density increases only slightly w i t h growth. R i b s reach the ventro-lateral  shoulder  apparently without being projected forward.  D I S C U S S I O N - O u r specimen is i n good agreement w i t h the lectotype of Arnioceras A. pluriphcata,  densicosta  and FUCINI's  w i t h w h i c h it is s y n o n y m y z e d herein. BRAGA et al. (1985) states the presence of sulci as the  distinctive difference between A. plunplicata  a n d A. densicosta  but sulci are clearly present on A.  densicosta  (GUERIN-FRANIATTE, 1966). T h e dense r i b b i n g p a t t e r n makes this species readily distinguishable from other species of  Arnioceras.  O C C U R R E N C E - K u n g a Island, Section T , Level 22; from the A r n o u l d i Zone.  D I S T R I B U T I O N - A.  densicosta  is k n o w n from the S e m i c o s t a t u m Zone of southern  Germany,  France  (GUERIN-FRANIATTE, 1966), S p a i n (BRAGA et al., 1985) a n d C h i l e (QUINZIO SINN, 1987) as well as from the Lower Sinemurian of Italy (FUCINI, 1902) and A l a s k a (IMLAY, 1981).  Arnioceras  cf. oppeli GUERIN-FRANIATTE, 1966 PI. 8, Fig. 1  *cf.  1966 Arnioceras  ? cf. cf. ?  1968 1976 1981 1987  Arnioceras Arnioceras Arnioceras Arnioceras  oppeli n. sp. - GUERIN-FRANIATTE, p. 267, p i . 143, fig. 1-3, text-fig. 132-134 (with synonymy) cf. oppeli GUERIN - FEDERICI, p. 122, fig 4e-f oppeli GUERIN-FRANIATTE - SCHLEGELMILCH, p. 48, p i . 20, fig. 5 cf. oppeli GUERIN-FRANIATTE, 1966 - SMITH, p. 145, p i . 2, fig. 1, 4 cf. oppeli GUERIN-FRANIATTE - QUINZIO SINN, p i . 2, fig. 13  T Y P E - H o l o t y p e : "Arnioceras  geometricum  OPPEL"  figured  by JAWORSKI, 1931, p i . 2, fig. 2, original  designation b y GUERIN-FRANIATTE, 1966, p. 267; refigured therein, p i . 143, fig. 1; deposited in the B a v a r i a n State M u s e u m of Geology and Paleontology, M u n i c h .  SYSTEMATIC  PALEONTOLOGY  A RIE  TIT IN A E  129  M A T E R I A L - 5 more or less fragmentary flattened external moulds preserved i n shale.  MEASUREMENTS SPECIMEN NO. K8J/1  DMAX 83.4 68.5  K9I/1  DESCRIPTION  UD 43.8 34.1  U  WH  52.4 49.8  - M e d i u m size, evolute f o r m w i t h moderately  ~19.5  PRHW ~24 18  wide u m b i l i c u s representing  about Vb of  diameter. V e n t e r bearing a keel. S m o o t h up to an u m b i l i c a l diameter of 5-7 m m , from w h i c h point sparse costation develops increasing i n frequency w i t h g r o l w t h . R i b s sharp, straight, rectiradiate b o t h on u m b i l i c a l wall and flanks, t e r m i n a t i n g a b r u p t l y at ventro-lateral shoulder, rib ends accentuated.  D I S C U S S I O N - T h e nomenclature as well as the morphology of the species is discussed i n detail by GUERINFRANIATTE (1966). O u r m a t e r i a l is i n good agreement w i t h A. oppeli i n terms of rib frequency, r i b b i n g style, and u m b i l i c a l ratio.  O C C U R R E N C E - K u n g a Island, Section S and T ; from the A r n o u l d i a n d V a r i a n s Zones.  D I S T R I B U T I O N - A. oppeli is a b u n d a n t i n the S e m i c o s t a t u m Zone of various localities i n northwest  Europe  (GUERIN-FRANIATTE, 1966). It is also k n o w n from the M e d i t e r r a n e a n province, e. g. the S e m i c o s t a t u m Zone of the B e t i c C o r d i l l e r a , S p a i n (BRAGA et a l , 1984), B u c k l a n d i and S e m i c o s t a t u m zones of Italy (FEDERICI, 1968). A. aff. oppeli is recorded from the O b t u s u m Zone of H u n g a r y (GECZY, 1972). In N o r t h A m e r i c a SMITH (1981) found A. cf. oppeli i n his A . ceratitoides Zone. In S o u t h A m e r i c a the S e m i c o s t a t u m Zone of n o r t h e r n C h i l e yielded the species (QUINZIO SINN, 1987).  SYSTEMATIC  PALEONTOLOGY  130  A RIE TIT IN A E  Arnioceras  cf. speciosum  FUCINI, 1902  PI. 9, Fig. 3, 6  * cf.  1902 Arnioceras  speciosum  n. sp. - FUCINI, p. 184, pi. 20, fig. 1-8; pi. 21, fig. 1-4  M A T E R I A L - 2 external and 2 internal moulds, incomplete and flattened, preserved in shale and siltstone.  MEASUREMENTS SPECIMEN NO. 7061/1 706P/1 S T 90-06  DESCRIPTION  DMAX 145.5 ~109 82  UD  U  81.5  56  60.2 45  55.2 54.9  - E v o l u t e , m e d i u m to large size form.  WH 37  PRWH 31 ~29 22  V e n t e r tricarinate-bisulcate. Dense a n d sharp  costation sets on at an u m b i l i c a l diameter of about 6 m m . R i b frequency increases steadily throughout ontogeny ( F i g . 6-11). R i b s somewhat rursiradiate on u m b i l i c a l wall, straight a n d rectiradiate on flanks and swing forward at the ventro-lateral shoulder to merge the lateral carina.  SYSTEMATIC P A L E O N T O L O G Y  A RIE TJTINA E  131  PRHW 30 -  20  10 QOI Fucini  Fucini 1902, pl.20, fig. 1  specimens  1902, pl.20, fig o-  0  ~i  1  -i  r  20  0  1  -i  r  r  40  UD Figure 6-11  1  60  80  (mm)  Rib frequency curves of Arnioceras speciosum.  DISCUSSION - According to BRAGA et al. (1985) this species is closely related to A. mendax, the only distinction between them being the sparser ribbing on the inner whorls of A. speciosum. In our opinion the difference is stronger when one compares the ribbing density curves, where A. mendax shows much slower rate of rib frequency increase.  The  differences between A. speciosum and A. arnouldi are discussed under A. arnouldi. A.  speciosum also differs from the A. ceratitoides group by its more pronounced projection of ribs.  OCCURRENCE - Tasu Sound, Section R, Kunga Island, Sections S and T; from the Arnouldi and Varians Zones.  SYSTEMATIC PALEONTOLOGY  ARIETITINAE  A G E A N D D I S T R I B U T I O N - A. speciosum  132  has only been recorded from Italy (FUCINI, 1902), where its  s t r a t i g r a p h i c position is not well constrained, a n d from the O b t u s u m Zone of H u n g a r y ( G E C Z Y , 1972).  Arnioceras  ex gr. ceratitoides  Q U E N S T E D T , 1849)  PI. 10, F i g . 1-2  MATERIAL  - 15 specimens  preserved  m o s t l y as flattened  i n t e r n a l and external moulds i n shale  and  silststone.  MEASUREMENTS SPECIMEN NO. Y L 8/3 YL11/7 YL7/11=15 YL8/1 K8U/1  DMAX 110.6 97.7 71.8 57.1 ~52  UD  U  58.5 51 36.4 25.4 ~23  52.9 52.2 50.7 44.5 44.2  WH  PRHW 22  26.6 17.9 18 ~15  22 15 17  D E S C R I P T I O N - E v o l u t e f o r m of m e d i u m size, whorls enlarging moderately r a p i d l y for genus. U m b i l i c u s usually less t h a n V2 of diameter, u m b i l i c a l ratio increasing w i t h g r o w t h . V e n t e r bearing a high keel. S m o o t h up to an u m b i l i c a l diameter of 5-10 m m , later densely r i b b e d . R i b s sharp, rectiradiate showing a tendency of b e c o m i n g gently rursiradiate at m a t u r i t y . R i b s slightly projected forward at the ventro-lateral shoulder.  DISCUSSION  - F U C I N I (1902) i l l u s t r a t e d a large n u m b e r  of specimen of A.  ceratitoides  and set up a  subspecies to accomodate a more sparsely r i b b e d forms. T h e diagnostic characteristics of the species include the u m b i l i c u s rather narrow for genus, a tendency of ribs to become rursiradiate, and a slow increase i n rib frequency. O t h e r , more n a r r o w l y interpreted species, such as A. rejectum F U C I N I , 1902 may differ f r o m A.  ceratitoides  FUCINI, 1902 and A.  italicum  i n w h o r l section and v e n t r a l features only. E v e n if these  SYSTEMATIC  PALEONTOLOGY  A RIE  TIT IN A E  133  differences were beyond intraspecific v a r i a t i o n , they do not allow d i s t i n c t i o n i n b a d l y preserved therefore here they are included i n A. ex gr. Arniotites  material,  ceratitoides.  begbiei CRICKMAY, 1928 is based o n poorly preserved fragmentary  type m a t e r i a l from  H a r b l e d o w n Island. It is considered uninterpretable and should be allowed to fall i n t o disuse. T h e rather high whorls and straight ribs may suggest affinity to the A. ceratitoides  group.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , K u n g a Island, Section S and T ; f r o m the A r n o u l d i and V a r i a n s Zones.  D I S T R I B U T I O N - A. ceratitoides  s. str. is frequently  cited from the S e m i c o s t a t u m Zone of northwest  E u r o p e . BLIND (1963) recorded a longer range i n c l u d i n g the O b t u s u m Zone. In the M e d i t e r r a n e a n province BRAGA et a l . (1984) reported the species from the S e m i c o s t a t u m Zone of the B e t i c C o r d i l l e r a of S p a i n , while i n Italy FERRETTI (1975) found it together  w i t h Paroxynoticeras  i n d i c a t i n g a higher ( O x y n o t u m Zone?)  level, although this identification was questioned b y DONOVAN (1990). The species is widely d i s t r i b u t e d outside E u r o p e as well. It is possibly present i n the western Pacific ( R O T H P L E T Z , 1882, S A T O , 1967). S o u t h A m e r i c a n occurrences include C o l o m b i a , E c u a d o r , P e r u , C h i l e and are confined to the m i d d l e part of the L o w e r S i n e m u r i a n (RlCCARDI et al., 1990). It was also found i n M e x i c o (ERBEN, 1956), N e v a d a (Arnioceras  humboldti of H Y A T T , 1869; SMITH, 1981), and O r e g o n (SMITH, 1981).  References to A. rejectum and A. italicum geographic range are narrower t h a n that of A.  Arnioceras  are less numerous i n the literature, their stratigraphic and  ceratitoides.  ex gr. mendax FUCINI, 1902 PI. 8, Fig. 2  M A T E R I A L - 2 external and 2 internal moulds, preserved extremely flattened i n shale.  SYSTEMATIC  PALEONTOLOGY  A RIE TIT IN A E  134  MEASUREMENTS SPECIMEN NO.  70.1 61 ~86 41.5  Y L 7/3 706H/1 K6J/1 K6L/9  DESCRIPTION 55-60%  UD  DMAX  of  U  39.8 35.9 53 22.0  WH  56.8 58.8 61.6 53.5  PRWH  17.8  _  12.3  19 23 19  - Shell of m e d i u m size, diameter ranges between 5-10 c m . E v o l u t e form, u m b i l i c u s represents  diameter.  Venter  bearing  prominent  keel,  further  details  obscured  by  two-dimensional  preservation. Nucleus s m o o t h up to an u m b i l i c a l diameter of 7 m m on the only specimen preserved w i t h inner whorls. R i b s straight, rectiradiate and dense on inner whorls w i t h rib frequency r e m a i n i n g constant or increasing only slowly. V e n t r a l t e r m i n a t i o n of ribs w i t h o u t projection or geniculation.  D I S C U S S I O N - In our rather poorly preserved m a t e r i a l A. mendax cannot be separated from A. dimorphum,  a closely related f o r m (in fact, their separate i d e n t i t y is questionable even w i t h well-preserved  specimens). A comprehensive  discussion of A.  mendax  i n c l u d i n g its subspecies  is given b y GUERIN-  PRANIATTE (1966). A n extremely short smooth stage i n d i c a t e d on her text-fig. 135 is not evident from FUCINI's (1902) figured specimens therefore cannot substantiate dimorphum.  a d i s t i n c t i o n between A. mendax a n d  A.  In FUCINI's m o n o g r a p h , A. mendax is amongst the most loosely interpreted species. O n the  other h a n d A. dtmorphum  has m u c h narrower v a r i a b i l t y falling w i t h i n the range of A.  mendax.  T h e straight, rectiradiate r i b b i n g w i t h o u t a v e n t r a l projection of the rib, together w i t h the little, if any, increase in rib frequency serve as a basis of differentiation from the A. ceratitoides  group, w h i c h tends  to have rursiradiate r i b b i n g i n m a t u r i t y ; A. oppeli, w h i c h shows a higher rate of rib frequency increase; and A. arnouldi,  w h i c h also possess projected ventral rib terminations.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , K u n g a Island, Section T ; from the A r n o u l d i Zone.  SYSTEMATIC  PALEONTOLOGY  A RIE  TI TIN A E  135  A G E A N D D I S T R I B U T I O N - A. mendax was originally described f r o m the S i n e m u r i a n of M o n t e d i C e t o n a , Italy (FUCINI, 1902). A s u m m a r y of the other Italian occurrences is given by FEDERICI (1968) who assigned B u c k l a n d i / S e m i c o s t a t u m Zone age to t h e m . GUERIN-FRANIATTE (1966) reports it from the S e m i c o s t a t u m Zone of F r a n c e . T h e species was also recorded from the O b t u s u m and O x y n o t u m zones of H u n g a r y , the latter is u n u s u a l l y high for the genus (GECZY, 1972). BRAGA et al. (1984) found the species i n the basal part of the S e m i c o s t a t u m Zone of the B e t i c C o r d i l l e r a , S p a i n . A.  dimorphum  was also found i n b o t h the Lower and U p p e r S i n e m u r i a n of Italy (FEDERICI, 1968).  BRAGA et al. (1984) recorded it from the O b t u s u m Zone of S p a i n . T h e only occurrence in. northwest E u r o p e was questionably reported by SPATH (1956) from the S e m i c o s t a t u m Zone of E n g l a n d .  Arnioceras  sp.  PI. 7, F i g . 5  M A T E R I A L - 3 small but complete specimens preserved as flattened impressions i n shale a n d an a d d i t i o n a l 18 fragments of specimens of various sizes w i t h similar preservation.  MEASUREMENTS SPECIMEN NO. 622B/1  622B/2  DMAX 28.0  24  UD  U  14.5 6.3  51.8  11.5  48  WH 7.8  PRHWR 17 15  6.5  17  D E S C R I P T I O N - Shell of m e d i u m size, evolute, u m b i l i c u s represents about V2 of diameter at juvenile stage, u m b i l i c a l ratio increases w i t h g r o w t h . V e n t e r tricarinate-bisulcate as far as preservation allows observation. Nucleus smooth up to an u m b i l i c a l diameter of 4 m m . R i b b i n g dense, frequency increases steadily w i t h growth based on fragments of different diameter. R i b s sharp, s l i g h t l y prorsiradiate on juvenile specimens to  SYSTEMATIC  A RIE TITINA  PALEONTOLOGY  E  136  slightly r u r s i r a d i a t e on larger fragments, curved gently forward on upper flank before m e r g i n g i n t o lateral carina.  D I S C U S S I O N - T h e lack of better preserved i n d i v i d u a l s precludes a full description and identification. T h i s f o r m seems to be the earliest representative of the genus i n the Queen C h a r l o t t e Islands.  O C C U R R E N C E - K e n n e c o t t P o i n t , Section B ; from the base of "Coroniceras" Zone.  S U B F A M I L Y A S T E R O C E R A T I N A E S P A T H , 1946 GENUS  TYPE  S P E C I E S - Ammonites  stellans  Asteroceras  S O W E R B Y , 1815 (p. 211, p i . 93) by subsequent designation (S.  B U C K M A N , 1911, p . 5) ( I C Z N O p i n i o n 324).  DESCRIPTION  - M i d v o l u t e forms  with  relatively r a p i d l y expanding, compressed  whorls. W h o r l  sides  converging above m i d flank, venter bearing p r o m i n e n t keel often, but not always a c c o m p a n i e d by lateral sulci. S t r o n g l y r i b b e d , ribs straight or slightly curved forward, r a d i a l or gently prorsiradiate. Sutures w i t h b r o a d , little incised saddles a n d shallow lobes.  R E M A R K S - Asteroceras  is a well-known genus consisting of numerous species. A l l species assigned to A. s.  str. were first described from E u r o p e , where northwest E u r o p e a n and M e d i t e r r a n e a n faunas contrast i n their respective specific content.  G U E R I N - F R A N I A T T E ' s (1966) comprehensive t r e a t m e n t is p r i m a r i l y concerned  w i t h representatives of the genus from F r a n c e m a i n l y belonging to northwest E u r o p e a n province (16 species described), whereas FUCINI's (1903) work discusses 9 species from Italy ( M e d i t e r r a n e a n province) - there are only t w o c o m m o n species. Despite this significant diversity one can notice a disproportionate n u m b e r of references to A. obtusum and A. stellare especially i n less detailed paleontological studies f r o m various parts  SYSTEMATIC  PALEONTOLOGY  137  ASTEROCERATINAE  of the world (for examples see s y n o n y m y lists below). A revision of these is needed for a more realistic picture of the paleobiogeography of the genus.  A G E A N D D I S T R I B U T I O N - Asteroceras  is a cosmopolitan genus confined to the O b t u s u m Zone except for  some precursors i n the T u r n e r i Zone. A s mentioned above it is a b u n d a n t i n b o t h faunal provinces of E u r o p e . O t h e r occurrences include C h i n a , J a p a n , N o r t h and S o u t h A m e r i c a .  Asteroceras  saltriense  ? ( P A R O N A , 1896)  PI. 10, F i g . 9  1903 1951 1985 1988 1990  cf. cf.  Asteroceras Asteroceras Asteroceras Asteroceras Asteroceras  saltriense P A R . - FUCINI, p. 186, p i . 33, fig. 4-6 cf. stellare Sowerby - F R E B O L D , p. 11, p i . 13, fig. 2 cf. suevicum ( Q U E N S T E D T ) - B R A G A et al., p. 97, p i . 1, fig. 5 cf. suevicum ( Q U E N S T E D T ) - M c F A R L A N E , p. 42, p i . 2, fig. 4-6 mendionalis nov. sp. - D O M M E R G U E S et al., p. 317, p i . 2, fig. 2-9; p i . 3, fig. 1  M A T E R I A L - F i v e specimens of poor to mediocre preservation as i n t e r n a l moulds i n shale or siltstone flattened  to various degrees; and  two specimens w i t h  three-dimensional but  one-sided preservation i n  sandstone.  MEASUREMENTS SPECIMEN NO. 706S/1  DMAX  UD  U  WH  <30.5 >22.5 20.2  32.6 32.9 27.0  <37.8 >29.8 30.7  16 15 15  54.7  14.5 16.0  17.4 19.1  14 14  42.0  13.2 17.0  26.5 31.7 31.4 %35  17.8 %20  13 15  D  <93 >68.3  MI/1  74.7  708S/1  50.5  YL11/4 28C1/1  «48  PRHW  D E S C R I P T I O N - M e d i u m size w i t h diameter of 5-10 c m . R a t h e r i n v o l u t e for genus w i t h a w h o r l overlap of 30-50%. W h o r l s enlarging moderately,  u m b i l i c u s m e d i u m wide. U m b i l i c a l  wall vertical with  rounded  SYSTEMATIC  PALEONTOLOGY  ASTEROCERATINAE  138  u m b i l i c a l shoulder. F l a n k s only slightly convex. V e n t e r not clearly seen, some i n d i c a t i o n of a b l u n t keel. S t r o n g a n d moderately dense r i b b i n g w i t h about 15 ribs per half w h o r l on adults. R i b s straight, r a d i a l or gently prorsiradiate, s t a r t i n g on u m b i l i c a l wall, somewhat  broadening ventrally and t e r m i n a t i n g at  the  ventro-lateral shoulder. Profile of ribs rounded triangular, interspace wider t h a n rib bases.  D I S C U S S I O N - O u r m a t e r i a l agrees satisfactorily w i t h the specimens of A. saltriense M e d i t e r r a n e a n localities. Some specimens of FUCINI's A.  varians  figured from various  (1903, e. g. p i . 32, fig. 1) also show  resemblance  i n i n v o l u t i o n and r i b b i n g density, however, others show ribs fading out on the flanks.  meridionalis  is s y n o n y m i z e d w i t h A. saltriense  A.  herein as there does not appear to be sufficient g r o u n d for  separation based on the a b u n d a n t illustration given i n DOMMERGUES et a l , 1990. In fact these authors emphasized the great s i m i l a r i t y to "A. cf. suevicum"  of BRAGA et al. (1985) j u s t i f y i n g the separation purely  by differing r i b b i n g density. A comparison of figures, however, reveals nearly i d e n t i c a l rib frequency, well w i t h i n intraspecific v a r i a t i o n . T h e remaining p r o b l e m i n need of resolution concerns the remarkable s i m i l a r i t y of A. saltriense A.  suevicum  and  as already p o i n t e d out b y BRAGA et al. (1985, p. 97). These authors s y n o n y m i z e d the two  forms, of w h i c h A. suevicum has p r i o r i t y , arguing for no substantial m o r p h o l o g i c a l difference. T h e i r separate specific i d e n t i t y is provisionally retained here, however, based on the m u c h larger size (characteristically 1020 cm) a n d narrower u m b i l i c u s at younger stage of A. suevicum. A.  suevicum  and A. obtusum as well as A. stellare  applicable to A.  A succinct s u m m a r y of differences between  is given by GUERIN-FRANIATTE (1966) and is equally  saltriense.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 13, Section I, Level 1; M a u d e Island, Section M , L e v e l 3; K u n g a Island, Section S, Level 28, Section T , Level 36 ; from the V a r i a n s Zone.  D I S T R I B U T I O N - In Southern Europe (Betic Cordillera: BRAGA et al. (1985), Lombardian Alps: PARONA (1896), Central Appenmes: FUCINI (1903), S wiss Prealps: DOMMERGUES et al. (1990)), in North America  SYSTEMATIC  PALEONTOLOGY  ASTEROCERATINAE  beside the Queen C h a r l o t t e Islands possibly from T y a u g h t o n Creek area  139  (FREBOLD,  1951). A l l stratigraphic  evidence suggest O b t u s u m Zone age.  Asteroceras  cf. varians FUCINI, 1903 PI. 10,  * cf.  1903 Asteroceras  pars cf.  "  Fig. 4,  6  varians n . sp. - FUCINI, p . 194, p i . 31, fig. 1-8; p i . 32, fig. 1-3  1988 Arctoasteroceras jeletzkyi FREBOLD, 1960 - McFARLANE, p . 48, p i . 1, fig. 7; p i . 2, fig. 1-2 1988 Asteroceras cf. obtusum (SOWERBY, 1817) - McFARLANE, p . 39, p i . 1, fig. 1-4 (non p i . 2, fig. 3 = Asteroceras aff. margarita) 1988 Asteroceras aff. varians FUCINI - CECCA et al., p . 70, p i . 1, fig. l a - b , 7-8  M A T E R I A L - E i g h t specimens of w h i c h s i x are flattened i n t e r n a l moulds i n shale a n d siltstone a n d t w o are three-dimensional b u t one-sided external m o u l d s preserved i n sandstone.  MEASUREMENTS SPECIMEN NO. YL11 YL106/1  DMAX 64.8 49.3  DESCRIPTION  UD  U  22.2 14.8  34.3 30.0  WH 26.4 19.7  PRHW 13 11  - S m a l l to m e d i u m size m i d volute form. U m b i l i c u s narrow for genus, whorls enlarging  moderately. U m b i l i c a l wall low b u t steep, u m b i l i c a l shoulder rounded. F l a n k s slightly convex. V e n t e r is not preserved. R i b b i n g c o m m o n l y not dense, varies extensively i n strength. R i b s straight, radial, o r i g i n a t i n g on u m b i l i c a l w a l l , t h i c k e n i n g o n m i d d l e flank t h a n fading out o n upper flank. Interspaces between ribs wider t h a n r i b bases.  D I S C U S S I O N - A s the name suggests, the species shows significant v a r i a b i l i t y , p a r t i c u l a r l y i n r i b b i n g strength  (FUCINI,  1903, p . 195).  FUCINI  himself  distinguished four  subspecies  to accommodate  differences. T h e identification of the present form w i t h any of these subspecies has not been a t t e m p t e d .  the  SYSTEMATIC  ASTEROCERA  PALEONTOLOGY  Ar do aster o ctr as jeletzkyi  TINAE  140  FREBOLD, 1960 is a species described from the Northwest T e r r i t o r i e s . It is  similar to our form i n v o l u t i o n and the fading of the ribs on the upper flanks. T h e p r i m a r y morphological difference, the presence of a keel on A. varians versus the smooth venter of Arctoasteroceras be p r o v e d i n the present m a t e r i a l . A. jeletzkyi, together w i t h Oxynoticeras Paltechioceras.  jeletzkyi,  cannot  however, occurs i n higher parts of the U p p e r S i n e m u r i a n  according to FREBOLD, while IMLA Y (1981) reported occurrences together w i t h  T h u s there m a y be sufficient stratigraphic g r o u n d for the d i s t i n c t i o n of these species even i n  poorly preserved m a t e r i a l .  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 13, Section I, Levels 2, 3, 6; K u n g a Island, Section S, Level 36; from the V a r i a n s Zone.  D I S T R I B U T I O N - A. varians  has only been k n o w n from the A p p e n i n e s , where CECCA et al. established  Lower L o t h a r i n g i a n age (i. e. O b t u s u m Zone equivalent) for it. DONOVAN (1990) suggests a Late O b t u s u m Zone age (Denotatus Subzone) based on morphological similarities to  Asteroceras  aff. margarita  Eparietites.  (PARONA, 1896)  PI. 10, Fig. 5  *aff. aff. pars aff. ? pars  1896 Arietites (Asteroceras) margarita sp. nov. - PARONA, p. 41, p i . 5, fig. 8 (refigured i n GUERIN-FRANIATTE, 1966, p i . 159) 1903 Asteroceras margarita PAR. - FUCINI, p. 187, p i . 32, fig. 4 (non fig. 5 = Asteroceras saltriense) 1966 Asteroceras margarita (PARONA, 1896) - GUERIN-FRANIATTE, p. 287, p i . 159-162 1981 Asteroceras (Eparietites) n . sp. - SMITH, p. 151, p i . 2, fig. 6, 8 1988 Asteroceras cf. obtusum (SOWERBY) - M c F A R L A N E , p. 39, p i . 2, fig. 3 (non p i . 1, fig. 1-4 = Asteroceras cf. varians)  T Y P E - H o l o t y p e : S t o p p a n i collection, M u s e o civico de M i l a n , figured by PARONA, 1896, p. 41, p i . 5, fig. 8, refigured b y GUERIN-FRANIATTE, 1966, p i . 159  SYSTEMATIC  PALEONTOLOGY  ASTEROCERA  141  TINAE  M A T E R I A L - Seven poorly preserved fragmentary flattened i n t e r n a l moulds i n siltsone and shale.  MEASUREMENTS SPECIMEN NO.  DMAX  D  UD  >120  708P/2  61 29.5 39.2 25.5  92.7  YL105/2  70.5 709E/1  %82  709P/1  %72  38.5 17.0 %30  37.0  YL11/3  U  16.3  s=48 42.3  WH  PRHW  %41  20 15  %37  %17 16  36.2 %47  %20 23.2  %42 44.0  %27 12.0  «17 12 %15 15  D E S C R I P T I O N - E v o l u t e f o r m a t t a i n i n g m e d i u m to large size (largest measured D > 1 2 0 m m ) . T h e poor preservation obscures three-dimensional details such as w h o r l section, venter, u m b i l i c a l wall. Coarsely ribbed, ribs gently prorsiradiate on u m b i l i c a l w a l l , t h e n inclined to become gently prorsiradiate from lower flank c o n t i n u i n g almost straight up to the ventro-lateral shoulder. Profile of ribs rounded triangular, sharper near the u m b i l i c u s and broadening v e n t r a l l y .  D I S C U S S I O N - N o n e of the k n o w n species of Asteroceras  shows a v o l u t i o n and ornament identical to that of  the Q u e e n C h a r l o t t e form. T h e closest resemblance can be observed w i t h A. margarita  w h i c h is, however,  characterized by denser r i b b i n g , p a r t i c u l a r l y on the inner whorls, and narrower u m b i l i c u s . A  reasonable  comparison can be made to some forms described as A. cf. stellare (FUCINI, 1903: p.184, p i . 30, fig. 5; HALL, 1987:  p. 1692, p. 1, fig. A - D ) but w i t h o u t seeing a similar rib t r e n d on the u m b i l i c a l wall and lower flank.  T h e most evolute  Asteroceras  described b y FUCINI (1903, A. volubile)  has a lower expansion rate. S h o u l d  the Q u e e n C h a r l o t t e f o r m represent a new species, our poorly preserved m a t e r i a l is inadequate to serve as a basis for comprehensive description.  A S TER O CERA  TINA  142  E  SYSTEMATIC  PALEONTOLOGY  OCCURRENCE  - Y a k o u n R i v e r , Section H , L e v e l 13, Section I, Level 5; K u n g a Island, S e c t i o n S, Level 25,  27, 36, 44; from the V a r i a n s Zone.  D I S T R I B U T I O N - A. margarita  is k n o w n from Italy a n d various localities i n F r a n c e (belonging to b o t h the  M e d i t e r r a n e a n a n d N o r t h w e s t E u r o p e a n provinces) from the O b t u s u m Zone. A t e n t a t i v e l y s y n o n y m i z e d form (SMITH, 1981) occurs in N e v a d a i n the A r n i o c e r a s ceratitoides a n d Paltechioceras harbledownense zones of SMITH.  G E N U S Hypasteroceras  T Y P E S P E C I E S - Asteroceras?  ceratiticum  S P A T H , 1923  FUCINI, 1903 ( L e c t o t y p e : p . 148, p i . 23, fig. l a - c , designated b y  D O N O V A N a n d F O R S E Y , 1973, p . 8) b y original designation ( S P A T H , 1923, p . 84)  S Y N O N Y M Y - Asaphoceras,  S P A T H , 1924 (see D O N O V A N , 1990, p . 258 for details).  D E S C R I P T I O N - M o d e r a t e l y evolute forms w i t h m e d i u m to wide u m b i l i c u s . W h o r l s h i g h w i t h ogival section. Diagnostic h i g h , acute keel on venter. S m o o t h or very faintly o r n a m e n t e d w i t h falcoid ribs. Sutures ceratiticlike on type species.  REMARKS  - W h e n erecting the genus S P A T H (1924) d i d not provide any i n f o r m a t i o n other  t h a n the  designation of the type species. D O N O V A N a n d F O R S E Y (1973) only added the f o r m a l designation of the lectotype of the type species. It was not u n t i l recently that a more detailed discussion o f the species content of genus was given b y D O N O V A N (1990). H i s list of species assigned to the genus includes t w o other species first k n o w n from Italy (H. exiguum (FUCINI, 1903) a n d H. montn (MENEGHINI, laevissimus"  1877)). "Ammonites  of Q U E N S T E D T (1883, p i . 13, fig. 18) was also questionably thought  falcames  to belong to this genus  ( B R A G A et a l . , 1984, p . 273),since it has a h i g h simple keel a n d only faint o r n a m e n t a t i o n .  SYSTEMATIC  PALEONTOLOGY  ASTEROCER  T h e asteroceratid affinity of the genus was rejected by  A  143  TINAE  DONOVAN (1990) on morphological as well  as stratigraphic grounds. I n our o p i n i o n , however, the available stratigraphic information (see below) does support an age range close to that of Asteroceras  and the relatively simple suture line w i t h broad, little  d i v i d e d lateral saddles is not far from that of Asteroceras.  Therefore the original placement  into  the  subfamily Asteroceratinae is retained here.  A G E A N D D I S T R I B U T I O N - T h e following paragraph is intended to provide a comprehensive review of the k n o w n occurrences of the genus. H. ceratitoides,  H. exiguum,  and H. raontii were described from M o n t e d i  C e t o n a in the C e n t r a l A p p e n i n e s b y FUCINI (1903). T h e locality is famous for its rich fauna beautifully illustrated i n the five volumes of FUCINl's work (1901-1905) w i t h o u t m u c h useful stratigraphic information. FISCHER (1971, 1972) a t t e m p t e d to recollect the condensed section to remedy the lack of biostratigraphy. He reported H. montn yielding  Dactilyoceratinae and  Arnioceras rather  (1971, p. 103-104) and H. exiguum Harpoceratinae  of probable  Carixian  age  and  above  beds yielding  assemblage. DONOVAN (1990) tends to interpret a break in the succession below Hyp  than  above  it  without  strong  reasoning.  T u r n e r i / O b t u s u m Zone age of the Hyp asteroceras Arnioceras  (1972, p. 44) from beds immediately below a bed  Stratigraphic  evidence  presented  below  an  asteroceras favors  a  fauna as it may follow from a direct relationship w i t h the  assemblage below a n d a hiatus above separating it from the P l i e n s b a c h i a n faunas.  H. montn has been recorded from other Italian localities in T u s c a n y : Gerfalco (FUCINI, 1898), A r i e t i (DE STEFANI, 1886), and M o n t e d i C o r e g n a (FEDERICI, 1968) w i t h o u t precise biostratigraphic data, also from P a l e r m o , Sicilia (GUGENBERGER, 1936) p r o b a b l y erroneously from the B u c k l a n d i Zone. F r o m S p a i n BRAGA et al. (1984a) figured H.? laevissimum  (p. 273, p i . 1, fig. 13) associated w i t h Arnioceras  also BRAGA et al. (1984b) listed H. exiguum correlated  with  the  Obtusum  Zone. H.?  as a member of their Asteroceras-Arnioceras  laevissimum  if indeed  referable  to  this  genus  ceratitoides; assemblage is the  only  representative occurring in the Nortwest E u r o p e a n province, namely i n the S c h w a b i a n A l b . T h e r e is no p u b l i s h e d occurrence of Hypasteroceras comparable f o r m w i t h sharp, non-sulcate keel as Arnioceras  outside E u r o p e , although SMITH figured a miserabile  (1981, p. 144, p i . 2, fig. 2) from his  SYSTEMATIC  ASTER  PALEONTOLOGY  O CERA  TINAE  144  A r n i o c e r a s ceratitoides Zone i n N e v a d a . T h e present author identified a specimen from T y a u g h t o n Creek as H. cf. montii ( G S C locality 117232) w i t h i n a rather unique association o r i g i n a t i n g p r o b a b l y from between the levels of a b u n d a n t Arnioceras  and echioceratid faunas (TIPPER, pers. c o m m . 1990)  Hyp asteroceras  ? sp.  PI. 9, F i g . 4-5  M A T E R I A L - T w o fragmentary specimens preserved as flattened impressions.  MEASUREMENTS SPECIMEN NO. YL101/4A YL101/4B  DMAX  D  %31.5 21.3  UD 12.5 8.9  U  WH  %39.7 41.8  10.1 11.8  D E S C R I P T I O N - S m a l l , very evolute form w i t h moderately enlarging whorls and m e d i u m wide u m b i l i c u s . H i g h keel persistent from an early stage ( U D % 2 m m ) . S m o o t h , no trace of ornament discernible.  D I S C U S S I O N - A m o n g the species listed above the closest comparison can be d r a w n to H. exiguum and H. ceratiticum,  the two differing m a i n l y i n s u t u r a l characteristics. O u r i n d i v i d u a l s differ from the several smooth  specimens figured b y FUCINI (1903, e. g. p i . 34, fig. 4, 5, 8) by being more evolute. T h e poor preservation (flattened state, loss of sutures) of the Queen C h a r l o t t e m a t e r i a l does not allow the establishment of specific identity.  O C C U R R E N C E - Y a k o u n R i v e r , Section I, L e v e l 1; from the V a r i a n s Zone.  SYSTEMATIC  PALEONTOLOGY  A S TER OCERA  G E N U S Epophioceras  TYPE  S P E C I E S - Ammonites  Landrioti  TINA  E  145  SPATH, 1924  D'ORBIGNY, 1850 (p. 213, N o . 33) nomen  dubium  clarified  by  THEVENIN (1907, p. 22, p i . 7, fig. 4-5) and refigured by GUERIN-FRANIATTE (1966, p i . 217). O r i g i n a l designation b y SPATH (1924, p. 204).  D E S C R I P T I O N - Large forms usually of 15-20 c m diameter sometimes a t t a i n i n g even larger size. V e r y evolute w i t h large u m b i l i c u s representing 55-70% of diameter. W h o r l section subcircular. V e n t e r s m o o t h bearing a weak keel w i t h or w i t h o u t faint sulci. O r n a m e n t consists of dense, simple, r a d i a l or prorsiradiate ribs.  R E M A R K S - T h e classification of Epophioceras  is discussed b y SCHLATTER (1984). He favoured i n c l u d i n g  the genus i n the E c h i o c e r a t i d a e while the t r a d i t i o n a l practice is to include it i n the Asteroceratinae (e.g. DONOVAN et a l , 1981), a practice followed here. Epophioceras 1973) and, i n t u r n , is derived f r o m Asteroceras  is the root stock of Echioceratidae (GETTY,  (DONOVAN, 1987). T h e separation af Asteroceratinae and  Echioceratidae is therefore i n e v i t a b l y arbitrary. T h e recurrent ammonites  m o r p h o l o g y of evolute, s i m p l y r i b b e d shells w i t h i n several groups of S i n e m u r i a n  poses problems for safe  include Vermiceras,  Metophioceras,  reliable identification, are  identification of Epophioceras. and Paltechioceras  missing on the  (cooccurrence w i t h Asteroceras  Queen  and Arnioceras),  no overlap of the v e r t i c a l range of Epophioceras  Heterochronous  homeomorph  genera  (DONOVAN, 1987). Sutures, w h i c h m a y allow more  Charlotte  material. Precise stratigraphic  information  however, enables unambigous determination since there is w i t h the genera listed above.  A comprehensive treatment of the genus is given by GUERIN-FRANIATTE (1966). M a n y reports i n the literature of the homeomorphs m e n t i o n e d above m a y represent Epophioceras; n u m b e r of specimens described and figured b y FUCINI (1902) as Vermiceras  a prominent example is a  (DONOVAN, 1990).  SYSTEMATIC  PALEONTOLOGY  ASTEROCERATINAE  146  A G E A N D D I S T R I B U T I O N - In northwest E u r o p e , where it is best understood, Epophioceras  occurs i n the  O b t u s u m Zone. In the M e d i t e r r a n e a n province it is k n o w n from numerous localities i n S p a i n ( B R A G A et a l , 1985), Italy (FUCINI, 1902), A u s t r i a ( H A U E R , 1856), and H u n g a r y ( G E C Z Y , 1972). O u t s i d e E u r o p e it has been  recorded  from  South  America  (Peru:  GEYER,  1979,  PRINZ,  1985;  Chile:  HlLLEBRANDT,  1981;  A r g e n t i n a : R l C C A R D I et a l , 1988) as well as N o r t h A m e r i c a ( N e v a d a : S M I T H , 1981; A l b e r t a : H A L L , 1987).  Epophioceras  aff. carinatum  SPATH, 1924  PI. 10, F i g . 3, 7-8  * aff. aff. aff. aff.  1867 1924 1956 1966  ?  1979 1981 1981 1981 1988  cf. cf.  Ammonites Landrioti (D'ORBIGNY) - DUMORTIER, p . 128, p i . 23, fig. 1-2 Epophioceras carinatum sp. nov. - SPATH, p. 204 Arnioceras monges-lopezi n . sp. - ERBEN, p. 274, p i . 31, fig. 5-6 Epophioceras carinatum SPATH, 1924 - GUERIN-FRANIATTE, p. 333, p i . 222-223, textfig. 183 Epophioceras s p , ex gr. carinatum SPATH - GEYER, p. 209, fig. 5e Epophioceras aff. carinatum SPATH, 1924 - SMITH, p. 158, p i . 3, fig. 4 Epophioceras cf. carinatum SPATH, 1924 - SMITH, p. 155, p i . 2, fig. 7, 9; p i . 3, fig. 1, 3 Epophioceras cf. cognitum GUERIN-FRANIATTE - HlLLEBRANDT, p. 506, p i . 3, fig. 2-3 Epophioceras cf. carinatum SPATH, 1924 - M c F A R L A N E , p. 47, p i . 1, fig. 6  M A T E R I A L - F i v e fragmentary specimens preserved as three-dimensional but one-sided i n t e r n a l moulds i n sandstone, two flattened i n t e r n a l moulds a n d one flattened external m o u l d i n shale.  MEASUREMENTS SPECIMEN NO. K9G/3 K9B/6 YL11/  DMAX  %110  D  UD  U  33.2 36.9  19.5 20.9 73.4 =«50  58.7  D E S C R I P T I O N - E v o l u t e f o r m a t t a i n i n g a m a x i m u m diameter representing  56.6 66.3  WH 8.1 8.3 21.7  PRHW 13 «15 %23 %18  over 10 c m . U m b i l i c u s increasingly wide  over 65% i n adults. V e n t e r bearing a rather well developed keel flanked b y shallow sulci.  SYSTEMATIC  PALEONTOLOGY  ASTEROCERATINAE  147  M o d e r a t e l y densely r i b b e d throughout, r i b b i n g density increasing only moderately w i t h g r o w t h . R i b s more strongly prorsiradiate i n juveniles. R i b s reach the ventro-lateral shoulder.  D I S C U S S I O N - O u r specimens assigned to E. aff. carinatum  fall into a smaller and a larger size group, the  latter unfortunately represented only by outer w h o r l fragments. T h u s their conspecific nature is somewhat questionable. T h e closest comparison can be made w i t h Epophioceras  carinatum,  although the Queen C h a r l o t t e  form differs by being smaller in size, less densely r i b b e d , and h a v i n g more prorsiradiate ribs. O t h e r closely related forms include E. longicella  and E. cognitum.  T h e m o r p h o l o g i c a l differences are  likely to justify the i n t r o d u c t i o n of a new species u p o n availability of more completely preserved material.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , L e v e l 13; K u n g a Island, Section S, Levels 31 a n d 35; from the V a r i a n s Zone.  D I S T R I B U T I O N - E. carinatum  is k n o w n from the O b t u s u m Zone of F r a n c e and also from P e r u . It m a y  doubtfully be present i n M e x i c o . Individuals more likely to be conspecific w i t h our m a t e r i a l have  been  recorded from N e v a d a (Arnioceras ceratitoides and Paltechioceras harbledownense zones of SMITH, 1981) and C h i l e (HlLLEBRANDT, 1981).  F A M I L Y E C H I O C E R A T I D A E BUCKMAN, 1913  R E M A R K S - T h i s family contains serpenticone, strongly and s i m p l y r i b b e d forms. Despite its relatively simple morphologic scheme the family has been the subject of extensive m o r p h o l o g i c a l s p l i t t i n g w i t h over 100 species erected (GETTY, 1972). T h e generic classification is comprehensively revised b y GETTY (1973) w h o recognized six genera, s y n o n y m i z e d thirteen, and treated three as nomma  dubia. A revision at the species  SYSTEMATIC  PALEONTOLOGY  ECHIOCERATIDAE  148  level by the same author remains u n p u b l i s h e d (GETTY, 1972). GETTY emphasized the taxonomic value of r i b b i n g patterns as a feature easily quantifiable and adequate for recognizing species. In the crushed material from the Queen C h a r l o t t e Islands the preservation also dictates the u t i l i t y of r i b b i n g as often the only available diagnostic feature. T h e m u l t i v a r i a t e analysis approach proposed by SMITH (1981) is not usable here since the number of useful morphologic variables is reduced b y poor preservation. In E u r o p e the echioceratids are of great b i o s t r a t i g r a p h i c value i n the O x y n o t u m and R a r i c o s t a t u m zones. T h e good stratigraphic c o n t r o l over our echioceratid collection enhances the reliability of taxonomic conclusions and m a y support the separation of some m o r p h o l o g i c a l l y very close but stratigraphically distant forms.  G E N U S Plesechioceras  T Y P E S P E C I E S -Echioceras  TRUEMAN et WILLIAMS, 1925  dehcatum BUCKMAN, 1914, b y original designation.  D E S C R I P T I O N - Serpenticone forms, r i b b i n g extremely dense from the innermost whorls later increasing only little i n frequency.  R i b s m a y be s l i g h t l y i n c l i n e d forward. V e n t e r bearing weak keel and may develop  faint sulci but no tricarinate stage attained.  R E M A R K S - Plesechioceras  was s y n o n y m i z e d w i t h Paltechioceras  by GETTY (1973). DOMMERGUES (1982)  reaffirmed its separate i d e n t i t y based on newly presented evidence regarding the basal R a r i c o s t a t u m Zone age of the type species (as opposed to the Late R a r i c o s t a t u m Zone age of Paltechioceras). the case for morphological differences, increasing r i b b i n g frequency, yakounense  Plesechioceras  differing from Paltechioceras  He also presented  b y its high a n d little  s l i g h t l y i n c l i n e d ribs, weak keel and complete lack of t r i c a r i n a t i o n . A s  is derived f r o m an even lower stratigraphic  level (probaly O x y n o t u m Zone equivalent)  otherwise falls i n t o this morphologic group, we are i n favour of retaining  Plesechioceras.  P. and  SYSTEMATIC  PALEONTOLOGY  ECHIOCERA  TIDAE  149  A G E A N D D I S T R I B U T I O N - A c c o r d i n g to DOMMERGUES (1982) the type species is derived from the base of the R a r i c o s t a t u m Zone i n F r a n c e . P. arcticum,  a species first k n o w n f r o m the C a n a d i a n A r c t i c (FREBOLD,  1975) is also recorded from S o u t h A m e r i c a (HlLLEBRANDT, 1987). P. yakounense  n . sp. extends the range of  the genus d o w n to the equivalent of the O x y n o t u m Zone.  Plesechioceras  yakounense  n sp.  PI. 12, F i g . 1-2, 5, 7  v pars  1981 Paltechioceras harbledownense p i . 5, fig. 1, 4 1988 Paltechioceras harbledownense only  (CRICKMAY, 1928) - SMITH, p. 187, p i . 4, fig. 9-10; (CRICKMAY, 1928) - M c F A R L A N E , p. 54, p i . 3, fig. 4-6  T Y P E - Holotype: Specimen Y L 1 4 / 3 0 (PI. 12, Fig. 2) Paratypes: Y L 1 5 / 1 1 (PI. 12, Fig. 1), Y L 1 4 / 3 2 ( P I . 12,  Fig. 5).  T Y P E L O C A L I T Y - Y a k o u n R i v e r , left bank (Section H , Level 16).  T Y P E H O R I Z O N - Base of the Harbledownense Zone.  E T Y M O L O G Y - N a m e d after the Y a k o u n R i v e r , the largest river i n G r a h a m Island exposing one of the best S i n e m u r i a n sections of the Q u e e n C h a r l o t t e Islands and serving as type locality.  D I A G N O S I S - C o s t a t i o n very dense and steadily increasing in frequency. c u r v e d forward. V e n t e r bearing a low keel w i t h faint sulci.  M A T E R I A L - 14 specimens preserved as flattened impressions in shale.  R i b s prorsiradiate  a n d slightly  SYSTEMATIC  PALEONTOLOGY  ECHIOCERA  TIDAE  WH  PRHW  150  MEASUREMENTS SPECIMEN NO.  DMAX  UD  U «  Holotype (YL14/30) Paratypes YL15/11 YL14/32  58  32.5  56  15.5  35  86 81  49 47  57  19.5 19  42 38  58  D E S C R I P T I O N - M e d i u m sized, diameter less t h a n 10 c m . E x p a n s i o n rate slow to moderate, w h o r l overlap a p p r o x i m a t e l y 10%. U m b i l i c u s representing developed keel. O n e u n u s u a l l y embedded  50-60% of diameter. Larger size specimens show trace of well fragment  of venter  indicates shallow sulci and faint  striation  forming forward directed chevron. N o evidence of lateral carinae. C o s t a t i o n dense from early stages, number of ribs >10 at an u m b i l i c a l diameter of 3 m m , >20 at 10 m m , increasing steadily through ontogeny ( F i g . 612). R i b s strong, sharp, prorsiradiate, gently c u r v e d forward. S t r e n g t h of r i b b i n g may decrease on adult body chamber.  SYSTEMATIC P A L E O N T O L O G Y  ECHIOCERA  TIDAE  151  DISCUSSION - P. yakounense differs from both P. ? harbledownense and Paltechioceras aff. boehmi in its ribbing pattern.  P. ? harbledownense shows more slowly increasing rib frequency curve, whereas that of P.  aff. boehmi becomes constant and then decreases. Furthermore P. ? harbledownense attains larger size and the loss of ribbing strength is more significant on its last whorl. Paltechioceras aff. boehmi is characterized by more rapidly enlarging whorls therefore narrower umbilicus. P. ? aklavikense differs in having more pronounced forward curved ribs. The type species P. delicatum has more slender whorls.  OCCURRENCE - Yakoun River, Sections H, I and K; Kunga Island, Section T; from the lower part of the  PRHW  40 -  30  20  10 -  Holotype Parctypes Other QCI specimens 0 0  40  20  UD n=24  Figure 6-12  (mm)  y=0.58x+14.13  r=0.86  Rib frequency curves of PltsechioceTds yakounense.  SYSTEMATIC  PALEONTOLOGY  ECHIOCERA  TIDAE  152  Harbledownense Zone.  D I S T R I B U T I O N - Besides the Q u e e n C h a r l o t t e Islands the species is k n o w n from N e v a d a (Harbledownense and R o t h p l e t z i zones of SMITH, 1981).  Plesechioceras  ? cf. aklavikense  (FREBOLD, 1975)  P L 12, Fig. 6, 8  cf.  1960 Echioceras  sensu lato sp. indet. - FREBOLD, p . 17, p i . 5, fig. 1-3  * cf.  1975 Echioceras  aklavikense  T Y P E - H o l o t y p e : Echioceras  F r e b o l d sp. nov. - FREBOLD, p . 9, p . 2, fig. 2-9  FREBOLD, 1975, p i . 2, fig. 2, G S C T y p e N o . 14638.  aklavikense  M A T E R I A L - 6 specimens preserved as flattened i n t e r n a l moulds i n shale. MEASUREMENTS SPECIMEN NO. 709Q/1 YL23/51  DMAX  UD  U  46 41  %58 %53  %79 %77  WH 19.5 19  PRHW 21 23  D E S C R I P T I O N - E v o l u t e f o r m of m e d i u m size. U m b i l i c u s wide, representing more t h a n 50% of diameter. W h o r l section not k n o w n . V e n t e r bearing a well developed, rounded, non-sulcate keel as seen on a v e n t r a l fragment associated w i t h a larger specimen. Inner whorls densely ribbed, r i b frequency increasing very little t h r o u g h ontogeny ( F i g . 6-13). R i b s robust, rectiradiate, c u r v e d forward strongly at t w o - t h i r d of flank e n d i n g rather a b r u p t l y at ventro-lateral shoulder.  SYSTEMATIC  PALEONTOLOGY  ECHIOCERA  TIDAE  D I S C U S S I O N - FREBOLD (1975) provides a detailed description of the ontogenic development  153  of w h o r l  section and venter. D o u b t remains i n the identification of our specimens as no s u c h information is available. T h i s f o r m is very closely related to P. ? harbledownense  from w h i c h it differs b y its strongly forward curved  ribs not losing strength on outer whorls and b y its non-sulcate keel. T h e i r rib frequency curves, however, are nearly i d e n t i c a l . M o r e a b u n d a n t and better preserved m a t e r i a l may prove t h e m conspecific. A m o n g the Paltechioceras  species described from E u r o p e P. bavaricum  is the closest m o r p h o l o g i c a l l y but it differs from  our f o r m i n its lower rib density and frequent irregular, looped ribs.  O C C U R R E N C E - Y a k o u n R i v e r , Section H ; M a u d e Island, Section M ; K u n g a Island, Section S; from the Harbledownense Zone.  D I S T R I B U T I O N - P. ? aklavikense  is k n o w n from the R i c h a r d s o n M o u n t a i n s , N o r t h w e s t Territories, and  M e l v i l l e Island of the A r c t i c A r c h i p e l a g o from beds correlated w i t h the R a r i c o s t a t u m Zone of E u r o p e but yielding no other ammonites (FREBOLD 1960, 1975).  Plesechioceras  ? harbledownense  (CRICKMAY, 1928)  PI. 11, F i g . 1-5  ? * ? pars pars  1889 1928 1981 1988  T Y P E - Melanhippites  Arniotites or Celtites (species uncertain) - WHITEAVES, p. 147, p i . 19, fig. 4 Melanhippites harbledownense sp. nov. - CRICKMAY, p. 61, p i . 3; p i . 4, fig. a-d (?) Paltechioceras cf. P. harbledownense (CRICKMAY) - IMLAY, p. 34, p i . 4, fig. 17, 22 only Paltechioceras harbledownense (CRICKMAY, 1928) - M c F A R L A N E , p. 54, p i . 4, fig. 3, 11 only  harbledownense  CRICKMAY, 1928, holotype: p i . 3 ( G S C T y p e N o . 25679), refigured  herein as P I . 11, F i g . 1; paratypes: p i . 4, fig. a-d ( G S C T y p e N o . 25680-25683), paratypes 1 and 2 refigured herein as P I . 11, F i g . 5 and 3, respectively. GETTY (1973, p. 26) considered the holotype lost and designated the p a r a t y p e 1 as neotype quoting a w r i t t e n c o m m u n i c a t i o n w i t h CRICKMAY who believed this specimen more characteristic to the species t h a n  SYSTEMATIC PALEONTOLOGY  ECHIOCERA  154  TIDAE  the other paratypes. T h e fact that the holotype is in existence renders GETTY's designation of neotype invalid.  M A T E R I A L - A p p r o x i m a t e l y 40 specimens preserved mostly as flattened internal moulds in shale.  MEASUREMENTS SPECIMEN NO. YL20/7 YL20/1 YL22/2  DMAX  UD  U  %180  104 64 88 56 57  %58  %140 97  WH  PRHW  28  %62  -  59  27 27  D E S C R I P T I O N - E v o l u t e f o r m a t t a i n i n g large size (diameter over 15 c m ) . W h o r l s enlarging more r a p i d l y t h a n t y p i c a l of genus. V e n t e r bears a keel possibly flanked b y sulci but no lateral carinae. Inner whorls densely r i b b e d . R i b b i n g frequency increasing very little w i t h growth ( F i g . 6-13). R i b s prorsiradiate, straight on inner whorls and slightly arcuate at larger diameter. R i b strength decreases on outer whorls, at large size irregular riblets replacing p r i m a r y ribs.  ECHIOCERA  SYSTEMATIC P A L E O N T O L O G Y  TIDAE  155  PRHW 30 — ^^^^n.  .jm  — • -~—  -A  _ o «  •—'  20 -  ,...-<  .••••**"  ...„::::::-•  ::  /  10 —  0  QCI spacirr ens Plesechioceras? ho bledownense  Q ~l specimens PlesechU ceras ? aklavikense  Holotyp I Plesechioceras ? he 'bledownense  P irotype No. 2 Plesechioc r a s ? harbledownense  1  0  1  1  i  i  i  20  i  i  40  UD  Holotype P B s s c h i o c e r a s ? aklavikenac  i  I  60  I  I  80  (mm)  P. ? harbledownense: n=23 y=0/141x+19.52 r=0.49 P. ? aklavikense: n=9 y=0.191x+14.90 r=0.65  Figure 6-13  Rib frequency curve of Plesechioceras  ? harbledownense and P. ?  aklavikense.  DISCUSSION - CRICKMAY's holotype is a plaster cast of an extremely poorly preserved, flattened external mould showing only the outer two whorls of a larger specimen, whereas the paratypes are fragments of smaller specimens. The species is the type of the genus Melanhippites CRICKMAY, 1928, a genus regarded by G E T T Y (1973) as a nomen dubium. This judgment can be extended to the species itself, as there is considerable doubt whether the fragmentary paratypes represent the same species as the crushed holotype. The species here is interpreted by the holotype showing high and stable rib frequency and weakened ribs on the outer worls, features readily recognizable in the present better preserved material. It should be emphasized that our material originates from the Sandilands Formation which is correlative with and perhaps identical to the Harbledown Formation, which yielded the type material. Paratype 2 is assumed to be conspecific whereas the other two paratypes including the "neotype" designated by G E T T Y (1973) are too  SYSTEMATIC  PALEONTOLOGY  incompletely preserved  E CHIO  for meaningful  comparison. A c c o r d i n g  originates from a level well above Arnioceras  CER  A TID A E  to CRICKMAY  156  (1928)  and it is associated w i t h Asteroceras  the  type  material  (confirmed b y TIPPER,  1976). T h e exposures at the type locality are h i g h l y faulted ( H . W . TIPPER, pers. c o m m . ) . T h e inner whorls of P. ? harbledownense ribbed forms such as P. yakounense,  are p r a c t i c a l l y indistinguishable from those of other densely  Paltechioceras  cf. rothpletzi,  and Paltechioceras  they all differ i n h a v i n g more densely r i b b e d outer whorls. P. ? aklavikense  aff. boehmi. However,  can be distinguished b y its more  arcuate ribs. O v e r and above the rejection of Melanhippites  as nomen  dubium by G E T T Y (1973) the  generic  assignment of this species remains a p r o b l e m . B o t h morphological and stratigraphical evidence point to an echioceratid affinity (contrasting the arnioceratid allocation proposed originally by CRICKMAY, 1928 and advocated b y FREBOLD i n FREBOLD and position suggests assignment Leptechioceras,  LITTLE, 1962). T h e rib frequency curve and low stratigraphic  to Plesechioceras  , the high last w h o r l and obsolete  whereas allocation to Paltechioceras  -  r i b b i n g is a feature of  is also a justifiable alternative (BREMER, 1965).  O C C U R R E N C E - Y a k o u n R i v e r , Section H ; M a u d e Island, Section M ; K u n g a Island, Sections S and T ; from the Harbledownense Zone.  D I S T R I B U T I O N - T h e type locality and the Queen C h a r l o t t e Islands are the only uncontested of the species, w h i c h m a y also be present i n the U p p e r S i n e m u r i a n of A l a s k a (IMLAY, 1981).  G E N U S Paltechioceras  T Y P E S P E C I E S - Paltechioceras  eliticum  BUCKMAN, 1924  BUCKMAN, 1924, p. 483  S Y N O N Y M Y - See G E T T Y (1973) for a detailed discussion.  occurrences  SYSTEMATIC  PALEONTOLOGY  ECHIOCERA  157  TIDAE  D E S C R I P T I O N - Densely r i b b e d serpenticones w i t h a compressed w h o r l section. V e n t e r carinate, most often bisulcate and may a t t a i n tricarinate stage.  A G E A N D D I S T R I B U T I O N - In E u r o p e Paltechioceras  is c o m m o n i n the R a r i c o s t a t u m Zone of b o t h the  Northwest E u r o p e a n and M e d i t e r r a n e a n provinces. It first appears i n the M a c d o n e l l i Subzone and reaches its acme i n the A p l a n a t u m Subzone (GETTY, 1973). It is generally held that the genus became extinct by the end of S i n e m u r i a n (DONOVAN, 1987). It is k n o w n from b o t h N o r t h and S o u t h A m e r i c a . Occurrences from other parts of the world may be h i d d e n i n the literuture due to the easy confusion w i t h h o m e o m o r p h E a r l y S i n e m u r i a n forms (e.g. Vermiceras,  Metophioceras).  Paltechioceras  cf. romanicum  (TJHLIG, 1900)  P L 13, F i g . 1  cf. cf. cf.  1956 Orthechioceras romanicum (UHLIG) totonacorum n . subsp. - ERBEN, p. 339, p i . 40, fig. 4-5 1965 Paltechioceras romanicum cf. romanicum - BREMER, p. 140, p i . 13, fig. 1 1965 Paltechioceras romanicum anatolicum n . subsp. - BREMER, p. 141, p i . 13, fig. 2  M A T E R I A L - 2 specimens, one i n t e r n a l and one external m o u l d preserved extremely flattened i n shale.  MEASUREMENTS SPECIMEN NO.  DMAX  YL29/3  %90  YL29/1  %85  UD  U  WH  «62 35 53 37  %68  19  %62  17  PRHW  23 23  D E S C R I P T I O N - E v o l u t e form of m e d i u m size, diameter less t h a n 10 c m . U m b i l i c u s wide, a p p r o x i m a t e l y 65%  of diameter. T r a c e of a well developed keel but  presence of sulci cannot  be j u d g e d due to poor  preservation. Densely r i b b e d , rib frequency r a p i d l y increasing up to an u m b i l i c a l diameter of 10-15 m m  SYSTEMATIC PALEONTOLOGY  20  ECHIOCERA  TIDAE  158  -  10 —  Pqltechioceros cf. QCI specimerls Holotype P. rothpletzi Bose 1894. pl.56 fig.5  Paltecr ioceras cf. rothpletzi 3CI specimens P< Itechioceras sp. Ssecimen H35/1  0 0  20  40  UD  60  80  100  (mm)  P. cf. romanicum: n=15 y=0.289x+14.85 r=0.62 P. cf. rothpletzi: n=10 y=0.542x+18.33 r=0.56 P. sp.: n=8 y=0.034x+22.60 r=0.25  Figure 6-14 P. sp.  Rib frequency curve of Paltechioceras cf. romanicum, P. cf. rothpletzi, and  remaining nearly constant later with approximately 23 ribs per half whorl (Fig. 6-14). Ribs rather sharp, strongly rursiradiate.  DISCUSSION - P. romanicum was synonymized with P. tardecrescens by GETTY (1972) in an effort to minimize the number of species within the oversplit genus Paltechioceras. The main arguments presented were overall similarity and resembling rib frequency curves. In our opinion P. romanicum should be retained based on its characteristic rursiradiate ribbing trend what makes it easily distinguishable from all other species of Paltechioceras.  OCCURRENCE - Yakoun River, Section H, Level 31; from the Harbledownense Zone.  SYSTEMATIC PALEONTOLOGY  ECHIOCERA  D I S T R I B U T I O N - In E u r o p e P. romanicum  TIDAE  159  is confined to the M e d i t e r r a n e a n P r o v i n c e where it occurs in  A n a t o l i a , T u r k e y (BREMER, 1965), the C a r p a t h i a n M t n s , R u m a n i a (UHLIG, 1900), and T h e  Southern  A p p e n i n e s , Italy (ONETTI, 1915). O u t s i d e E u r o p e it is also k n o w n from M e x i c o (ERBEN, 1956). BREMER correlated it w i t h the highest S i n e m u r i a n A p l a n a t u m Subzone, s u p p o r t i n g ERBEN's allocation of the species into his uppermost S i n e m u r i a n " U n i t of Microderoceras  Paltechioceras  bispmatum  cf. rothpletzi  altespmatum".  (BOSE, 1894)  PI. 13, Fig. 5  * cf. cf. cf. cf. cf. cf. cf.  1894 1902 1914 1965 1981 1985 1988  Arietites rothpletzi Bose - BOSE, p. 730, p i . 56, fig. 5 Vermiceras rothpletzi (BOSE) - FUCINI, p. 139, p i . 12, fig. 12 Echioceras rothpletzi (BOSE) - B U C K M A N , p. 96c Paltechioceras rothpletzi (BOSE) - BREMER, p. 143, p i . 13, fig. 4 Paltechioceras rothpletzi (BOSE, 1894) -SMITH, p. 193, p i . 5, fig. 5-6; p i . 6, fig. 1 Paltechioceras cf. rothpletzi (BOSE, 1894) - PRINZ, p. 180, p i . 4, fig. 3 Paltechioceras (?) aff. rothpletzi (BOSE) - CECCA et a l , p i . 1, fig. 5-6  M A T E R I A L - 2 specimens preserved as flattened i n t e r n a l m o u l d i n shale.  MEASUREMENTS SPECIMEN NO. YL32/1 YL32/2  DMAX 75.8 22  UD  U  47 36 15  62 68  WH 16.8 5  PRHW _  33 28  D E S C R I P T I O N - Serpenticone shell w i t h slowly enlarging whorls and wide u m b i l i c u s . V e n t e r not seen. Inner whorls extremely densely r i b b e d . R i b frequency increasing up to an u m b i l i c a l diameter of approximately 10 m m where number of ribs can exceed 30 per half w h o r l . R i b s straight, rectiradiate to gently prorsiradiate.  SYSTEMATIC  ECHIOCERA  PALEONTOLOGY  D I S C U S S I O N - P. rothpletzi  160  TIDAE  is the most densely r i b b e d species of the genus. T h e Q u e e n C h a r l o t t e specimens  compare  favourably w i t h  the  s y n o n y m i z e d m a t e r i a l except  for their  tendency  of m a i n t a i n i n g a  nearly  constant  rib frequency at later g r o w t h stage. T h i s form differs from other echioceratids o c c u r r i n g i n the  Q u e e n C h a r l o t t e Islands i n its denser costation coupled w i t h a very wide u m b i l i c u s .  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 34; from the upper p a r t of the Harbledownense Zone.  D I S T R I B U T I O N - P. rothpletzi  is T e t h y a n i n d i s t r i b u t i o n being reported f r o m the Bavarian A l p s (BOSE,  1894), A n a t o l i a (BREMER, 1965) a n d and Italy (FUCINI, 1902) in E u r o p e as well as from P e r u (PRINZ, 1985) and N e v a d a (SMITH, 1981). It is restricted to the uppermost S i n e m u r i a n .  Paltechioceras  aff. boehmi ( H U G , 1899) PI. 12, F i g . 3-4  * aff.  1899 Arietites  aff.  1902 Vermiceras  boehmi n . sp. - H U G , p . 16, p i . 12, fig. 8 boehmi H U G - FUCINI, p. 141, p i . 12, fig. 13  aff.  1914 Echioceras  boehmi (HUG) - B U C K M A N , p. 96c  aff.  1958 Paltechioceras  aff.  1972 - G E T T Y , p. 222, p i . 8, fig. 3  aff.  1981 Paltechioceras  boehmi ( H U G , 1899) - S M I T H , p. 176, p i . 4, fig. 1-2  aff.  1986 Paltechioceras  bohemi (HUG) (sid)  aff.  1987 Paltechioceras  boehmi (HUG) - D O M M E R G U E S and M E I S T E R , p. 319, p i . 3, fig. 6-16;  pars  1988 Paltechioceras  boehmi ( H U G , 1899) - M C F A R L A N E , p. 56, p i . 4, fig. 5, 6, 8 o n l y  1988 Paltechioceras  cf. rothpletzi  boehmi ( H U G ) - D O N O V A N , p. 26, p i . 2, fig. 5 (?), 6  - PALLINI, p i . 1, fig. 2  p i . 4, fig. 1-4  %  2(1)  (BOSE, 1894) - M c F A R L A N E , p. 58, p i . 4, fig. 10, 12; p i . 5,  .  ? pars '  1988 Paltechioceras  aff. boehmi ( H U G ) - C E C C A et a l . , p i . 1, fig. 9 only  aff.  1989 Paltechioceras  boehmi ( H U G ) - D O M M E R G U E S and M E I S T E R , p. 465, p i . 2, fig. 6-11;  p i . 3, fig. 2, 5 aff.  TYPE  1990 Paltechioceras  - L e c t o t y p e : Arietites  '  boehmi ( H U G ) - D O M M E R G U E S and M E I S T E R , p. 319, p i . 4, fig. 2-3  boehmi  H U G , 1899, p i . 12, fig. 8, designated  deposited i n the Naturhistorisches M u s e u m , B e r n , w i t h no n u m b e r .  by  DONOVAN,  1958, p . 26;  ECHIOCERA  SYSTEMATIC P A L E O N T O L O G Y  161  TIDAE  MATERIAL - Approximately 35 specimens preserved as flattened internal moulds, some of them with shelly film, in shale.  MEASUREMENTS SPECIMEN NO.  27.5 21.9 18.5  49.5 44 38.8  YL30/25 YL32/21 YL31/22  U  UD  DMAX  PRHW  WH  55 49.8 47.7  28 23 23  13 12.5 11  PRHW 30 — •  20  —  10 — • QCI s p e c i m e n s Paltechioceras aff. b o e h m i ~i  0  1  1  r  1  1  L e c t o t y D e P. b o e h m i H a u g , 18|92 , p i . 1 2 , f i g . 8 1  10  1  ~i  1  20  UD  (mm)  Paltechioceras aff. boehmi n=32 y=0.627x+14.58 r=0.66  Fig. 6-15  Rib frequency curve of Paltechioceras aff. boehmu  1  r  30  SYSTEMATIC  PALEONTOLOGY  DESCRIPTION  ECHIOCERA  - E v o l u t e form of small size, diameter  TIDAE  162  t y p i c a l l y around 5 c m . W h o r l s enlarging rather  r a p i d l y for genus, u m b i l i c u s approximately half of diameter. Some i n d i c a t i o n of a keel w i t h o u t lateral carinae. Inner whorls very densely r i b b e d , rib frequency increasing up to 10-15 m m of u m b i l i c a l diameter and 20-30 ribs per half w h o r l then decreasing slightly ( F i g . 6-15). R i b s sharp, prorsiradiate, curved gently forward at ventro-lateral shoulder.  D I S C U S S I O N - T h e densely r i b b e d inner whorls and the convex u p w a r d rib frequency favourably w i t h  P.  boehmi. Nevertheless our specimens  curve  differ from it in their less slender  compare  whorls and  narrower u m b i l i c u s . P. rothpletzi seems  to  be  Plesechioceras  can be distinguished by the steady climb of its rib frequency curve. P . aff. boehmi also  closely  related  ? aklavikense,  to  Plesechioceras  yakounense,  Plesechioceras  ?  harbledownense,  and  their differences are discussed under these species.  O C C U R R E N C E - Y a k o u n River, Section H , Levels 32-34; from the Harbledownense Zone.  D I S T R I B U T I O N - P. boehmi is k n o w n from b o t h Northwest E u r o p e (GETTY, 1972) and the M e d i t e r r a n e a n P r o v i n c e (FUCINI, 1902, PALLINI, 1986) but it is most a b u n d a n t i n their transitional region representing the northern m a r g i n of the T e t h y s (e. g. Swiss Prealps, DOMMERGUES a n d MEISTER, 1987). GETTY (1972) determined its range in B r i t a i n from the top of the M a c d o n e l l i Subzone extending to the A p l a r i a t u m Subzone. DOMMERGUES and MEISTER's results suggest an early M a c d o n e l l i (1987) or late R a r i c o s t a t u m Subzone age for the species.  Paltechioceras  sp.  PL 13, Fig. 6  M A T E R I A L - One shelly specimen preserved one-sided and compressed i n shale.  SYSTEMATIC PALEONTOLOGY  ECHIOCERA  TIDAE  163  MEASUREMENTS SPECIMEN NO.  DMAX  UD  U  128  83  65  YL33/1  DESCRIPTION  - Serpenticone  PRHW  WH 26.5  27  w i d e l y u m b i l i c a t e form. F l a n k s slightly convex, ventro-lateral  shoulder  r o u n d e d , venter not seen. Inner whorls densely r i b b e d w i t h a n u m b e r of ribs exceeding 20 per half w h o r l at an u m b i l i c a l diameter of 5 m m , later r e m a i n i n g largely unchanged  as density of ribs decreasing on outer  whorls. R i b s stout, gently prorsiradiate, sharper on inner whorls becoming broader and more rounded at later stages.  D I S C U S S I O N - T h e inner whorls of this specimen resemble those of Plesechioceras harbledownense,  and Paltechioceras  aff. boehmi.  c o n t i n u o u s l y increasing t r e n d of rib frequency  Plesechioceras  ? yakounense  whereas Paltechioceras  ? yakounense,  P. ?  can be distinguished b y its  aff. boehmi tends to show a slight  decrease i n that along w i t h a higher expansion rate. P. ? harbledownense  can be distinguished from the  present f o r m by the weakening of ribs o n outer whorls at comparable size. None of the E u r o p e a n species is closely comparable w i t h the present form. T h e assesment of the i d e n t i t y of the only available i n d i v i d u a l m u s t await the discovery of more m a t e r i a l .  O C C U R R E N C E - Y a k o u n R i v e r , S e c t i o n H , L e v e l 35; from the upper part of the Harbledownense Zone.  F A M I L Y O X Y N O T I C E R A T I D A E H Y A T T , 1875 G E N U S Oxynoticeras  T Y P E S P E C I E S - Ammonites 1909, p . 2).  oxynotus  H Y A T T , 1875  Q U E N S T E D T , 1843 (p. 161) by subsequent designation ( B U C K M A N ,  SYSTEMATIC  PALEONTOLOGY  S Y N O N Y M Y - Hyp oxynoticeras  OX YNO  TICER  A  TIDAE  164  SPATH, 1925  D E S C R I P T I O N - Involute, compressed forms with narrow umbilicus. Whorl section lanceolate with a sharp venter. Ornament consisting of fine ribs in some cases confined to lower flank. Sutures closely spaced and highly complex.  AGE A N D DISTRIBUTION -  Oxynoticeras  is distributed worldwide in the Upper Sinemurian. It is most  characteristic of the Oxynotum Zone but ranges as high as the basal Jamesoni Zone of the Pliensbachian (GECZY, 1976). Besides the numerous European occurrences the genus is also known from North America (Arctic Canada: FREBOLD, 1960; Nevada: SMITH, 1981; Mexico: ERBEN, 1956). The only recorded from South America (HlLLEBRANDT, 1981) may belong to Radstockiceras ex gr.  (see Discussion under R.  numismale).  Oxynoticeras  cf. simpsoni  (SIMPSON,  1843)  PI. 14, Fig. 2  cf. cf. pars cf. * cf. cf. cf. ?  1876 1886 1912 1961 1976 1981 1988  Oxynoticeras  Amaltheus simpsoni SIMPSON - TATE and BLAKE, p. 291, pi. 8, fig. 4 Oxynoticeras oxynotum (QUENSTEDT) - GEYER, p. 231, pi. 2, fig. 12, 13 Aetomoceras simpsoni BEAN - SIMPSON - BUCKMAN, pi. 66A and B Oxynoticeras simpsoni (Simpson) - DEAN et a l , pi. 67, fig. 4 Oxynoticeras simpsoni (SIMPSON) - SCHLEGELMILCH, p. 53, pi. 22, fig. 11 Oxynoticeras cf. simpsoni (SIMPSON, 1843) - SMITH, p. 207, pi. 7, fig. 1-2 Oxynoticeratide ? - CECCA et a l , p. 70, pi.2, fig. 5  T Y P E - Holotype figured by BUCKMAN, 1912, pi. 66A and B .  M A T E R I A L - 4 specimens preserved as flattened impressions with shelly film in shale.  SYSTEMATIC  PALEONTOLOGY  OXYNOTICERA  165  TIDAE  MEASUREMENTS SPECIMEN NO.  DMAX  YL14/3 YL14/11  98 69.5 65 50  YL14/24 YL14/9  DESCRIPTION  UD  U  11 7.5 5 5.3  WH  11.2 10.8 7.7 10.6  54 34.5 40 24.5  - Involute shell w i t h narrow u m b i l i c u s . Preservation obliterates  any  three-dimensional  details. Shell appears to be entirely smooth.  D I S C U S S I O N - G i v e n the flattened preservation any identification is necessarily tentative. T h e u m b i l i c u s of our i n d i v i d u a l s is narrower t h a n that of the type m a t e r i a l . T h e lack of r i b b i n g appears to be the diagnostic characteristic suggesting comparison w i t h O.  most  simpsoni.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 16; from the Harbledownense Zone.  D I S T R I B U T I O N - In N o r t h w e s t E u r o p e , O. simpsoni  is characteristic of the S i m p s o n i Subzone of the  O x y n o t u m Zone (DEAN et a l , 1961). SMITH (1981) records  0.  cf. simpsoni  from his U p p e r S i n e m u r i a n  R o t h p l e t z i Zone of N e v a d a .  G E N U S Gleviceras BUCKMAN, 1918  T Y P E S P E C I E S - Gleviceras  glevense BUCKMAN, 1918 by original designation (BUCKMAN, 1918, p. 289). G.  glevense is a subjective j u n i o r s y n o n y m of G. subguibalianum  ( P l A , 1914) (DONOVAN, 1958).  S Y N O N Y M Y - Glevumites,  BUCKMAN, 1918; Riparioceras,  1962;  Tutchericeras,  BUCKMAN, 1924; Guibaliceras,  B U C K M A N , 1918; Victoriceras,  BUCKMAN, 1918.  SCHINDEWOLF,  SYSTEMATIC  OXYNOTICERATIDAE  PALEONTOLOGY  D E S C R I P T I O N - Closely related forms to Oxynoticeras  166  a t t a i n i n g large size. W h o r l section ogival, venter  sharp at y o u n g stage becoming r o u n d e d w i t h g r o w t h . K e e l confined to inner whorls. R i b b i n g of variable strength and density present on different species.  AGE  A N D D I S T R I B U T I O N - Gleviceras  is c o m m o n i n the U p p e r S i n e m u r i a n of b o t h the  Northwest  E u r o p e a n and M e d i t e r r a n e a n provinces. T h e genus ranges up to the J a m e s o n i Zone (GECZY, 1976). It is also k n o w n from P e r u (PRINZ, 1985) and N e v a d a (SMITH, 1981).  Gleviceras  cf. subguibalianum  ( P l A , 1914)  PI. 13, F i g . 2-3  cf. pars cf. * cf. cf. cf. cf. cf. cf.  1881 1914 1956 1958 1965 1973 1976 1985 1987  Amaltheus Guibalianus - WRIGHT, p. 385, p i . 45, fig. 1, 2, 5 (non 3, 4) Oxynoticeras subguibalianum n . sp. - P l A , p. 11, 96, p i . 5, fig. 5; p i . 6, fig. 9; p i . 9, fig. 1 Oxynoticeras (Radstockiceras) palomense n . sp. - ERBEN, p . 349, p i . 37, fig. 5 Oxynoticeras (Gleviceras) subguibalianum PlA- DONOVAN, p . 11, p i . 1 Gleviceras cf. subguibalianum (PlA, 1914) - BREMER, p. 147 Gleviceras subguibalianum (VON P l A , 1914) - DONOVAN a n d FORSEY, p. 9, p i . 2, fig. 1 Gleviceras subguibalianum (PlA) - SCHLEGELMILCH, p . 54, p i . 23, fig. 1 Gleviceras subguibalianum (PlA 1914) - PRINZ, p. 181, p i . 4, fig. 6 Gleviceras aff. subguibalianum (PlA) - DOMMERGUES and MEISTER, p . 318, p i . 1, fig. 9, 12-13  cf.  1988 Gleviceras 1989 Gleviceras  sp. indet. - M c F A R L A N E , p. 53, p i . 6, fig. 1 aff. subguibalianum (VIA.) - DOMMERGUES and MEISTER, p . 464, p i . 1, fig. 1  M A T E R I A L - 3 specimens preserved as flattened impressions i n shale.  MEASUREMENTS SPECIMEN NO. YL15/13 YL15/2  DMAX 95 79  UD 22.7 15  U 23.9 18.9  WH 40 33  SYSTEMATIC  PALEONTOLOGY  OXYNO  TICERA  TIDAE  167  D E S C R I P T I O N - Involute f o r m a t t a i n i n g a diameter of nearly 10 c m . U m b i l i c u s moderately narrow and deep. B o d y chamber nearly V2 w h o r l long. F i n e l y ribbed; ribs rectiradiate, somewhat broadening ventrally, swinging forward near the ventro-lateral shoulder. O n a smaller specimen occasionally i n t e r c a l a t i n g secondary ribs originate at lower t h i r d of flank.  D I S C U S S I O N - F r o m the three closely related species of Gleviceras victoris)  (G.  subguibalianum,  the best comparison of our m a t e r i a l can be d r a w n w i t h G. subguibalianum.  G. dons and  G.  T h e best agreement seen  is w i t h the P e r u v i a n specimen figured by PRINZ (1985, p i . 4, fig. 6). T h e other species possess somewhat coarser r i b b i n g , G. dons is further distinguished by its narrower u m b i l i c u s and more frequent secondary ribs.  OCCURRENCE  - Yakoun  River,  Section H , Level  17; K u n g a Island, Section T , L e v e l 42; from  the  Harbledownense Zone.  D I S T R I B U T I O N - G. subguibalianum  is k n o w n p r i m a r i l y from the O x y n o t u m Zone of b o t h  Northwest  E u r o p e (SCHLEGELMILCH, 1976) and the M e d i t e r r a n e a n P r o v i n c e (BREMER, 1965) as well as from South A m e r i c a (PRINZ, 1985).  G E N U S Radstockiceras  TYPE  SPECIES  -  Radstockiceras  complicatum  BUCKMAN, 1918  BUCKMAN,  1918  (p.  287, p i . 27, fig. 1) b y original  designation.  S Y N O N Y M Y - Carixiceras Kleistoxynoticeras Retenticeras  SPATH, 1925; Fastigiceras  BUCKMAN,  B U C K M A N , 1920.  1925;  Metoxynoticeras  BUCKMAN, 1919; Homoxynoticeras SPATH, 1922;  Phylloxyconites  B U C K M A N , 1925; BUCKMAN,  1924;  SYSTEMATIC  DESCRIPTION  PALEONTOLOGY  OXYNOTICERA  TIDAE  168  - O x y n o t i c e r a t i d w i t h extremely narrow, p u n c t i f o r m or closed u m b i l i c u s . W h o r l section  compressed, lanceolate, venter sharp. O r n a m e n t t y p i c a l l y consisting of fine r i b b i n g .  R E M A R K S - Radstockiceras  is used here i n a broader sense according to BREMER (1965). S C H L A T T E R  (1980) retained the genus Metoxynoticeras  suggesting that any unification of genera s h o u l d depend u p o n  more thorough t a x o n o m i c revision. H i s view is not followed here as the preservation of our m a t e r i a l w o u l d not  allow  Fannmoceras  AGE  differentiation  of  these  genera  based  on  suture  lines. T h e . closely related  Pliensbachian  is regarded as a separate genus ( F R E B O L D , 1967, S M I T H and T I P P E R , i n prep.).  A N D DISTRIBUTION  - Radstockiceras  is k n o w n from the  Upper Sinemurian - Upper Carixian  (DONOVAN et a l , 1981) of b o t h N o r t h w e s t and M e d i t e r r a n e a n E u r o p e . It is most a b u n d a n t i n the J a m e s o n i Zone.  Radstockiceras  ex gr. numismale  (OPPEL, 1853)  PI. 13, F i g . 4  M A T E R I A L - O n e specimen preserved as flattened impression i n shale.  M E A S U R E M E N T S - Specimen N o . 2 8 A 3 / 1 D M A X = 3 6 . 3  DESCRIPTION  UD=3.4 U=9.4 WH=17.0  - Involute form w i t h narrow u m b i l i c u s representing less t h a n  10% of diameter.  Whorl  section and depth of u m b i l i c u s cannot be seen. V e n t e r w i t h sharp a n d h i g h keel. P r i m a r y ribs i n d i s t i n c t and rectiradiate on lower flank, bent slightly b a c k w a r d at  flank and projected forward a b r u p t l y shortly after.  R i b b i n g most prominent at ventro-lateral shoulder, where secondary ribs parallel to prorsiradiate part of primaries intercalated.  SYSTEMATIC  PALEONTOLOGY  OXYNO  TICER  A TIDA  E  169  D I S C U S S I O N - Our individual agrees reasonably well with two closely related species, R. numismale  and R.  oppeli (SCHLOENBACH, 1863). Similar ribbing pattern showing the peculiar trend of ribs can be seen in "Oxynoticeras numismale"  cf. lymense"  (non  of SCHLATTER (1980, p. 50, pi. 1, fig. 4), "Radstockiceras  p. 150, pi. 14, fig. 1), "Oxynoticeras numismale  W R I G H T ) of HlLLEBRANDT (1981, p. 507, pi. 3, fig. 7),  numismale"  complanosum"  "Metoxynoticeras  of BREMER (1965,  of FUCINI (1901, p. 6, pi. 1, fig. 11), Radstockiceras  of VENTURI, 1978, p.108, pi. 1, fig. 13, and  "Radstockiceras  ex gr.  oppeli" of HOFFMAN (1982, p. 150,  pi. 10, fig. 1; pi. 11, fig. 2 especially). Our individual, however, displays a well developed keel not seen in the above listed specimens. Nomenclatural problems of the subjective synonyms R. numismale  and R. complanosum  are clarified  by S C H L A T T E R (1980).  O C C U R R E N C E - Maude Island, Section M , Level 7; from the R e c o g n i t u m Zone.  D I S T R I B U T I O N - Both R. numismale  and R. oppeli are characteristic of the Jamesoni Zone of Northwest  Europe. They also occur at Tethyan localities: R. complanosum  (=_ff. numismale)  is reported from the  Jamesoni Zone (Polymorphus Subzone) of Anatolia, Turkey (BREMER, 1965) and CECCA et al. (1988) records "Metoxynoticeras  cf. oppeli" from condensed Upper Sinemurian beds in the Appenines, Italy. A  possible South American occurrence is known from Chile (HlLLEBRANDT, 1981, see Discussion).  Oxynoticeratidae gen. et sp. indet. PI. 14, Fig. 5  M A T E R I A L - One specimen preserved as flattened impression shale.  M E A S U R E M E N T S - YL48/15 DMAX=48.4  UD=6(' ) 7  WH=26(?)  PRHW=10(?)  SYSTEMATIC  PALEONTOLOGY  DESCRIPTION  - Involute form w i t h narrow u m b i l i c u s . U m b i l i c a l seam of last w h o r l not clearly seen due to  OXYNO  TICERA  TIDAE  170  b a d preservation. B o d y chamber nearly two t h i r d of a w h o r l . O r n a m e n t consisting of broad  rectiradiate  p r i m a r y ribs becoming prorsiradiate on body chamber a n d fading out near ventro-lateral shoulder. Fine, faint striation visible between primaries.  D I S C U S S I O N - T h e single, poorly preserved specimen does not permit identification. T h e closest comparison can be d r a w n w i t h Par oxynoticeras  pulchellum  (FUCINI, 1901). T h e five specimens originally figured by  FUCINI (1901) represent a wide array of r i b b i n g w i t h ribs v a r y i n g in number a n d stregth. O u r specimen shows greatest resemblance to FUCINI's PI. 1, F i g . 8. A n o t h e r figured example, originating from the Jamesoni Zone of H u n g a r y  (GECZY, 1976, p i . 1, fig. 2), has fewer ribs. A conclusion, however, must await further  finds of this form in the Q u e e n C h a r l o t t e Islands.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 50; f r o m the R e c o g n i t u m Zone.  S U P E R F A M I L Y E O D E R O C E R A T A C E A E SPATH, 1929 F A M I L Y E O D E R O C E R A T I D A E SPATH, 1929 G E N U S Crucilobiceras  T Y P E S P E C I E S - Crucilobiceras  DESCRIPTION  -  crucilobatum  E v o l u t e forms  with  BUCKMAN, 1920  B U C K M A N , 1920, by original designation.  slowly  enlarging  whorls  and  wide  umbilicus. W h o r l  section  subrectangular to ellipsoid, venter simple. R i b b i n g dense and persistent, ribs straight, bearing two distant rows of tubercles (spines on shelly i n d i v i d u a l s ) .  REMARKS  -  Crucilobiceras  and  Micro der ocer as  are  closely  related  genera  displaying  significant  morphological s i m i l a r i t y expressed b y the evolute shell w i t h bituberculate ornament. In our interpretation  SYSTEMATIC  PALEONTOLOGY  171  EODEROCERATACEAE  the difference between t h e m is b o t h stratigraphic a n d morphologic. Microderoceras include only late E a r l y S i n e m u r i a n ( T u r n e r i Zone) forms, whereas  Crucilobiceras  herein is restricted to is confined to the Late  S i n e m u r i a n ( m a i n l y R a r i c o s t a t u m Zone). T h e latter is also distinguished b y a tendency to develop secondary ribs  at later  Crucilobiceras  g r o w t h stages, this  is not seen  are more distant. Metaderoceras  i n Microderoceras.  A l s o the t w o rows of tubercles o n  was s y n o n y m i z e d w i t h Crucilobiceras  b y ARKELL (1957) a n d  DONOVAN a n d FORSEY (1973), b u t treated as an independent genus b y DONOVAN et al. (1981). T h e latter o p i n i o n is adopted here, since Metaderoceras  has only one row of tubercles a n d is restricted to the Lower  Pliensbachian.  is k n o w n from the R a r i c o s t a t u m Zone of N o r t h w e s t E u r o p e .  A G E A N D D I S T R I B U T I O N - Crucilobiceras  IMLAY (1981) reports the genus from the uppermost S i n e m u r i a n of A l a s k a .  Crucilobiceras  ? sp.  PI. 14, Fig. 1, 6; P I . 15, F i g . 3  M A T E R I A L - 3 specimens preserved as compressed i n t e r n a l moulds, t w o of t h e m w h o r l fragments o n l y .  MEASUREMENTS SPECIMEN NO. 1A4/1  YL48/18 YL41/1  DMAX  UD  U  «115  %60 %36  %52  %46  %21  %45  -  -  -  WH  PRHW  25.3 17 %15 16.3  14 %15  D E S C R I P T I O N - E v o l u t e form; u m b i l i c u s represents nearly half of diameter. W h o r l section a n d u m b i l i c a l shoulder rounded, as far as preservation allows observation. M o d e r a t e l y dense r i b b i n g bears t w o rows of  SYSTEMATIC  EODEROCERATACEAE  PALEONTOLOGY  tubercles, inner row about ^/j  172  of flank, outer row close to ventro-lateral shoulder. In one specimen 3 m m long  spines preserved. R i b s straight, rectiradiate, weak on u m b i l i c a l wall and lower flank, most prominent between tubercles, t e r m i n a t i n g a b r u p t l y at the outer one.  D I S C U S S I O N - T h e poor and fragmentary preservation does not allow specific identification. T h e style of ornament  is i n d i c a t i v e of Crucilobiceras,  as the  missing, and the tubercles are more distant t h a n i n  secondary  r i b b i n g characteristic to  Tetraspidoceras  is  Microderoceras.  O C C U R R E N C E - Y a k o u n R i v e r , Section H , L e v e l 43 and 50; central G r a h a m Island, Section L , Level 4; from the R e c o g n i t u m Zone.  F A M I L Y C O E L O C E R A T I D A E HAUG, 1910 . G E N U S Tetraspidoceras  T Y P E S P E C I E S - Ammonites  quadrarmatus  SPATH, 1926 .  DUMORTIER, 1869, p. 60, b y original designation (SPATH, 1926,  p. 47).  D E S C R I P T I O N - M i d v o l u t e to evolute forms, u m b i l i c u s m e d i u m to wide and shallow, w h o r l expansion rate slow to moderate. W h o r l section ellipsoid. V e n t e r convex, simple. O r n a m e n t consisting of dense p r i m a r y ribs bearing two distant spines or tubercles and simple intercalatory secondary ribs.  R E M A R K S - Tetraspidoceras  and its relationship to related genera (Microderoceras,  discussed by DONOVAN (1990a, b ) . In a slightly modified view, Tetraspidoceras  Vicidmoceras)  are  is taken here to include  forms somewhat variable i n v o l u t i o n and u m b i l i c a l w i d t h but unified by their bituberculate p r i m a r y and well developed secondary r i b b i n g . Species assignable to Tetraspidoceras (REYNES), T. reynesi SPATH, T. fila ('QUENSTEDT), T. nothum  include T. quadrarmatus,  (FUCINI), T. birchiades  T.  latispma  (ROSENBERG), T.  SYSTEMATIC  PALEONTOLOGY  fuelopi G E C Z Y , T. bimammatum al.  EODEROCERATACEAE  G E C Z Y , "Microderoceras  ? sp. A " and "Microderoceras  (1988, p i . 3, fig. 3-5, and fig. 2, respectively) as well as the  pacificum  and T.  173  sp. B " of C E C C A et  two new species i n t r o d u c e d herein,  T.  recognitum.  A G E A N D D I S T R I B U T I O N - In E u r o p e Tetraspidoceras  is characteristic of the R a r i c o s t a t u m a n d J a m e s o n i  zones. In N o r t h w e s t E u r o p e most records suggest earliest P l i e n s b a c h i a n age i n contrast to the M e d i t e r r a n e a n localities where the s t r a t i g r a p h y  is less well understood,  S i n e m u r i a n forms (e. g. Paltechioceras  Tetraspidoceras  and o x y n o t i c e r a t i d s ) . T. pacificum  is possibly present i n M e x i c o (Microderoceras cf. birchiades  but  aff. birchiades  often occurs together  with  occurs also i n C h i l e a n d the genus  of ERBEN, 1956) and N e v a d a  (Microderoceras  of SMITH, 1981).  Tetraspidoceras  pacificum  n . sp.  PI. 14, F i g . 4  1987 Microderoceras  H O L O T Y P E - Microderoceras  sp. - QUINZIO SlNN, p i . 3, fig. 1  sp. of QUINZIO SINN, 1987, p i . 3, fig. 1, specimen no. S A - 3 3 / 1 , deposited i n  the T e c h n i s c h e U n i v e r s i t a t , B e r l i n .  TYPE  L O C A L I T Y - Section 2, S i e r r a de A r g o m e d o / S i e r r a A s p e r a , C o r d i l l e r a D o m e y k o , N o r t h e r n C h i l e  (QUINZIO SINN, 1987, p. 45.)  T Y P E H O R I Z O N - O b t u s u m Zone (?)  E T Y M O L O G Y - pacificum Americas).  refers to the k n o w n geographic range of the species (the Pacific m a r g i n of the  SYSTEMATIC  PALEONTOLOGY  EODEROCERATACEAE  174  D I A G N O S I S - E v o l u t e form, whorls enlarging moderately rapidly. B i t u b e r c u l a t e , tubercles connected by 2-3 looped ribs. F r e q u e n c y of tubercles increasing slowly w i t h g r o w t h . 2-4 secondary ribs developed between each set of tubercles, equal in strength to p r i m a r y ribs except for the mature b o d y chamber where p r i m a r y r i b b i n g becoming coarser.  M A T E R I A L - O n e compressed e x t e r n a l m o u l d preserved i n shale.  MEASUREMENTS SPECIMEN NO. K6S/1 (Paratype) Holotype  DMAX  D  79.5  UD  U  40.6  51  55  46  %220 120  WH 22.6 % 70 37  THW 14  13  D E S C R I P T I O N - E v o l u t e f o r m w i t h little w h o r l overlap. U m b i l i c u s represents about 40% of diameter. W h o r l s e x p a n d i n g moderately r a p i d l y . W h o r l section ellipsoid, flanks and venter convex as far as it can be j u d g e d . M o d e r a t e l y densely r i b b e d a n d bituberculate throughout. F r e q u e n c y of tubercles increases little w i t h g r o w t h , number of pair of tubercles remains less t h a n 15 per half w h o r l (Figure 6-16). 2-3 looped ribs connecting tubercles, 2-4 secondary ribs intercalated between pairs of tubercles. A l l ribs of a p p r o x i m a t e l y equal strength. coalescence.  O n adult b o d y chamber p r i m a r y ribs become blunter and coarser w i t h a tendency of  SYSTEMATIC P A L E O N T O L O G Y  EODEROCERATACEAE  175  DISCUSSION - Its ornament makes the new species readily distinguishable from all previously described ones. No other representative of Tetraspidoceras shows looped ribs instead of simple primary ribs on the phragmocone. The Queen Charlotte individual agrees well with the holotype. The discovery of better and more completely preserved material is desirable as no suture line and undistorted whorl section is available yet.  OCCURRENCE - Kunga Island, Section T, Level 36; from the Harbledownense Zone.  THW 15  - i  '  -  10  5  Holot /pe (Quinzi ) Sinn, Par atype Kj S/1 19E 7, PI. 3, Fi g. 1) mV-  0  '  0  ...  1  I  10  ,  20  30  UD  Figure 6-16  1  1  40  1  50  (mm)  Tubercle frequency curve of Tetraspidoceras pacificum n. sp.  1  60  SYSTEMATIC  PALEONTOLOGY  EODEROCERATACEAE  D I S T R I B U T I O N - Besides the Queen C h a r l o t t e Islands, Domeyko  of  Epophioceras  Northern  Chile  (QUINZIO  SINN,  1987)  T. pacificum  where  it  176  is only k n o w n from the  occurs  together  with  Cordillera  Arnioceras  and  therefore the age of the assemblage is regarded as O b t u s u m Zone equivalent. Its stratigraphic  position i n the Q u e e n C h a r l o t t e Islands is higher as it cooccurs w i t h  Tetraspidoceras  recognitum  Paltechioceras.  n . sp.  PI. 14, F i g . 8; P I . 15, Fig. 1, 4  ? pars ?  1899 Microderoceras nothum M G H . in sch. - FUCINI, p. 247, p i . 20, fig. 3 only 1900 Microderoceras cfr. Heberti OPPEL - FUCINI, p. 161, p i . 21, fig. 3  T Y P E - H o l o t y p e : Specimen 2 8 A 2 / 1 [m]. Paratypes: Specimen 93749 [M] and Y L 4 8 / 1 0 .  T Y P E L O C A L I T Y - M a u d e Island, section M . -  T Y P E H O R I Z O N - R e c o g n i t u m Zone.  E T Y M O L O G Y - recognitum  - ( L a t i n "revealed, recognized") for the species h a v i n g been k n o w n since the  t u r n of the century w i t h o u t the recognition of its separate i d e n t i t y .  D I A G N O S I S - E v o l u t e shell w i t h moderately enlarging whorls. B o d y chamber of a p p r o x i m a t e l y one w h o r l . Densely r i b b e d and strongly bituberculate, tubercles being more prominent t h a n ribs.  M A T E R I A L - 1 m a c r o c o n c h , 1 m i c r o c o n c h and 6 smaller size specimens without obvious sign of m a t u r i t y ; all are preserved as compressed i n t e r n a l moulds or flattened impressions i n shale.  SYSTEMATIC  PALEONTOLOGY  177  EODEROCERATACEAE  MEASUREMENTS SPECIMEN NO.  DMAX  UD  U  .WH  PRHW  2 8 A 2 / l a [m]  90.7  45.1  49.7  26.4  22  (Holotype) YL48/10 (Paratype)  83.4  38.5  47.4  23.3  19  29.0 18.8  49.1 %48  %18 11.5  15 14  68  24  59.0 %39  YL48/1 28A2/lb C-93749 [M] (Paratype)  DESCRIPTION  172  %310  -  Macroconch:  E v o l u t e shell  55.4  of large  size,  diameter  nearly  30 c m . U m b i l i c u s  wide  representing almost 55% of diameter. U m b i l i c a l w a l l low, u m b i l i c a l shoulder r o u n d e d . W h o r l section p r o b a b l y ellipsoid w i t h slightly convex flanks. V e n t e r b e a r i n g no keel. B o d y chamber one w h o r l long. P h r a g m o c o n e rather w o r n , no ornament preserved. On  b o d y chamber gently prorsiradiate ribs of broad, low, and r o u n d e d profile  tubercles located at ^ / y and ^/j  of flank. N o secondary ribs present.  connect sharp,  conical  SYSTEMATIC P A L E O N T O L O G Y  178  EODEROCERATACEAE  Microconch: Shell of medium size, maximum diameter not exceeding 10 cm (one of the specimens shows a flared rib parallel to peristome, believed to indicate maturity at a diameter of 91 mm). Umbilicus representing approximately half of diameter. Similarly to macroconch, body chamber one whorl long showing better preserved ornament. Persistently densely ribbed (Fig. 6-17) and bituberculate. Tuberculation more prominent than ribbing. Phragmocone eroded on all specimens, although some short spines preserved on outer tubercles. Ribs rursiradiate on umbilical wall becoming rectiradiate on flanks, strongest between tubercles and fading out beyond the outer tubercles. 2-3 faint secondary fibs intercalated between primary ones.  PRHW •  20 -  **  // /  1/ / F / MS  /If fl/ 'If  15 —  f..  *  *  *  *  *  *  **  *  v.'  10 Holo ype [m] 28A2 /1 A  5 —  QCI specimens [n  0  '  1  1  1  •  0  i  — i — i — i — i —  25  , ]  Paratype [M] C-93749 •  Paratype [m ] YL48/10 •>  ni 1899 PI. 2 1. Fig. 3 -  Fucini 1900 PI. 21, •ig- ^  — i — i — i — i —  50  —i—r  i  A.  t  75  T  -  1  t •  100  UD ( m m ) QCI [m] specimens n= 19 y=0.302x+8.00 r=0.93  Figure 6-17  Primary rib frequency of Tetraspidoceras recognitum.  1  i -i  — i — i — i —  125  150  SYSTEMATIC  PALEONTOLOGY  EODEROCERATACEAE  179  D I S C U S S I O N - T w o specimens figured by FUCINI (1899, 1900, see s y n o n y m y list) display a style of ornament nearly identical to our m a t e r i a l a l t h o u g h the first one is a juvenile i n d i v i d u a l . O t h e r closely related include Microderoceras  forms  sp. B of CECCA et a l . (1988, p i . 3, fig. 2) distinguished b y the dominance of ribs over  tubercles and Microderoceras  aff. birchiades  (FERRETTI, 1975, p i . 23, fig. 1; PALLINI 1986, p i . 1, fig. 5) w h i c h  possess coarser r i b b i n g .  T h e new species is t h o u g h t to be d i m o r p h w i t h a [M]:[m] ratio of a p p r o x i m a t e l y 3:1. A l l but one i n d i v i d u a l fall into a 5-10 c m m a x i m u m diameter range (microconchs), i n c l u d i n g a clearly mature specimen (as indicated by a flared rib at the peristome). A m u c h larger i n d i v i d u a l (macroconch), originated probably from the same horizon, shares most morphologic characteristics.  OCCURRENCE  - Y a k o u n River,  Section H , Level 50, M a u d e  Island,  Section M , Level 8; from  the  R e c o g n i t u m Zone.  D I S T R I B U T I O N - T h e two s y n o n y m i z e d specimens were collected f r o m T u s c a n y and the C e n t r a l A p p e n i n e s , Italy. N o precise stratigraphic information is available.  Tetraspidoceras  sp.  PI. 14, F i g . 7  ?  1956 Microderoceras  sp. indet. - ERBEN, p. 364, p i . 41, fig. 12  ?  1981 Microderoceras  cf. birchiades  ROSENBERG, 1909 - SMITH, p. 241, p i . 10, fig. 2  M A T E R I A L - One w h o r l fragment (one t h i r d of a whorl) preserved as compressed internal m o u l d .  SYSTEMATIC  DESCRIPTION  PALEONTOLOGY  -  Whorl  expansion  EODEROCERATACEAE  rate  suggests  moderately  wide  180  umbilicus.  Ornament  changing,  b i t u b e r c u l a t e at the beginning w i t h p r i m a r y ribs strongest between tubercles and w i t h 2-3 weak secondary ribs, later tubercles  becoming bullate then levelled into much, coarser  p r i m a r y ribs while secondary  ribs  disappear. Tubercles located a p p r o x i m a t e l y I/5 and ^ / g of flank.  D I S C U S S I O N - T h e change in ornament possibly represents the beginning of m a t u r i t y between  the phragmocone  and adult body chamber.  Reasonable  and  differences  comparison can be d r a w n between  our  i n d i v i d u a l and T. nothum w h i c h also loses secondary ribs on the b o d y chamber (see lectotype: FUCINI, 1899, p i . 21, fig. 1), but nevertheless has a slower expansion rate. T. birchiades  also displays similar ornament but  p r o b a b l y has a wider u m b i l i c u s . T h i s species, however, is poorly defined the type (ROSENBERG, 1909, p i . 13,  T h e herein questionably s y n o n y m i z e d material consists of unfortunately  s i m i l a r l y fragmentary  and  imperfectly preserved w h o r l fragments hence comparison is l i m i t e d .  O C C U R R E N C E - Y a k o u n R i v e r , Section H , Level 17; from the base of Harbledownense Zone.  D I S T R I B U T I O N - O n e of the doubtfully s y n o n y m i z e d forms occurs i n the U p p e r S i n e m u r i a n of M e x i c o (Unit  of  Microderoceras  bispmatum  altespinatum  Harbledownense Zone of N e v a d a (SMITH, 1981).  of  ERBEN,  1956),  the  other  is  derived  from  the  SYSTEMATIC  PALEONTOLOGY  BIVALVIA  181  C L A S S B I V A L V I A LlNNE SUBCLASS PTERIOMORPHIA O R D E R P T E R I O I D A NEWELL, 1965 S U B O R D E R P T E R I I N A NEWELL, 1965 S U P E R F A M I L Y P E C T I N A C E A RAFINESQUE, 1815 F A M I L Y E N T O L I I D A E TEPPNER, 1922 G E N U S Posidonotis LOSACCO, 1942  T Y P E S P E C I E S - Posidonotis  S Y N O N Y M Y - Pectmula  damelln LOSACCO, 1942, b y m o n o t y p y .  LEANZA, 1943  D E S C R I P T I O N - F l a t , t h i n , discoidal shells w i t h p e c t i n i d triangular auricles on b o t h valves. Shell ornament consisting of regular concentric folds a n d r a d i a l ribs resulting i n reticulate p a t t e r n . A u r i c l e s bearing growth lines only.  R E M A R K S - A complete revision of the genus is given b y DAMBORENEA (1987).  AGE  A N D DISTRIBUTION  - I n N o r t h A m e r i c a Posidonotis  is k n o w n from the U p p e r S i n e m u r i a n of  C a l i f o r n i a a n d B r i t i s h C o l u m b i a . T h e S o u t h A m e r i c a n occurrences ( A r g e n t i n a , C h i l e ) are restricted t o the U p p e r P l i e n s b a c h i a n - L o w e r T o a r c i a n , while E u r o p e a n  localities ( i n Italy a n d Greece)  species are most p r o b a b l y of T o a r c i a n age. T h e r e exist uncertain  yielding the type  records of the genus from J a p a n a n d  northeast Siberia. T h e d i s t r i b u t i o n p a t t e r n is discussed i n detail b y DAMBORENEA (1987, 1989).  SYSTEMATIC  PALEONTOLOGY  BIVALVIA  Posidonotis  semiplicata  182  ( H Y A T T , 1894)  PI. 14, F i g . 3; PI. 15, F i g . 2  *  1894 1894 1928 1933 1933  Monotis semiplicata n . sp. - HYATT, p. 414 Monotis symmetrica n . sp. - HYATT, p. 414 Entolium balteatum sp. nov - CRICKMAY, p. 62, p i . 4, fig. e-g 'Monotis semiplicata" HYATT, 1894 - CRICKMAY, p. 52, p i . 14, fig. 4-7 "Monotis symmetrica" HYATT, 1894 - CRICKMAY, p. 52, p i . 14, fig. 1-3  T Y P E - Monotis  semiplicata  HYATT, 1894, subsequent designation b y CRICKMAY, 1933, p. 52; deposited i n  the U . S. N a t i o n a l M u s e u m , N o . 30192.  M A T E R I A L - T h e species c o m m o n l y occur crowding particular b e d d i n g planes. H a n d specimens of such surfaces were studied.  D E S C R I P T I O N - T h i n , flat shells of subcircular outline, c o m m o n l y 1 to 1.5 c m in length, rare full-grown specimens up to 3 c m . Shells equivalve, nearly equilateral. A n t e r i o r and posterior auricles present on b o t h valves, though u m b o n a l region rarely preserved fully, p a r t l y due to c o m m o n l y overlapping i n d i v i d u a l s . D o r s a l m a r g i n forming an angle less t h a n 1 8 0 ° . O r n a m e n t consisting of concentric folds and straight r a d i a l ribs resulting  in a reticulate  pattern.  T h e i r relative strength  variable  with  concentric  elements  typically  prevailing.  D I S C U S S I O N - T h e three N o r t h A m e r i c a n n o m i n a l species ( P . semiplicata,  P. symmetrica  and P.  balteata)  are s y n o n y m y z e d following the practice of DAMBORENEA (1987, 1989). H Y A T T ' s two forms differ o n l y due to post-depositional distortion. CRICKMAY's d i s t i n c t i o n of P. balteata  was based on differences i n strength of  concentric and radial ribs w h i c h is considered to fall w i t h i n intraspecific v a r i a t i o n . P. cancellata, the S o u t h A m e r i c a n uppermost  known from  Pliensbachian-lowermost T o a r c i a n , is very closely related (DAMBORENEA,  S Y S T E M A T I C  BIVALVIA  P A L E O N T O L O G Y  183  1987) and further comparative studies are p l a n n e d to decide whether or not it is conspecific w i t h our f o r m ( D A M B O R E N E A , w r i t t e n comm.)  OCCURRENCE  - Y a k o u n R i v e r , Section H ; M a u d e Island, Section M ; K u n g a Island, Section S; from the  R e c o g n i t u m Zone.  D I S T R I B U T I O N - T h e type m a t e r i a l originates from the Sailor C a n y o n F o r m a t i o n i n A m e r i c a n C a n y o n , C a l i f o r n i a . T h e type of Entolium  balteatum  comes from the H a r b l e d o w n F o r m a t i o n , H a r b l e d o w n Island; the  species is also k n o w n from neighboring V a n c o u v e r Island ( J E L E T Z K Y , 1976). Its local biostratigraphic in the  Queen  reported  it  (Crucilobiceras,  Charlotte from  the  Islands was first Wrangell  Plesechioceras  Mtns,  recognized Alaska.  ? harbledownense)  I M L A Y , 1968, 1981, C A M E R O N and T I P P E R , 1985).  b y C A M E R O N and Wherever  available,  TIPPER scarce  (1985). I M L A Y associated  value (1981)  ammonites  are i n d i c a t i v e of Late S i n e m u r i a n age ( C R I C K M A Y , 1928,  CONCLUSIONS  184  CHAPTER 7  CONCLUSIONS  T h i s thesis presents the first detailed systematic s t u d y of latest H e t t a n g i a n to earliest S i n e m u r i a n ammonites  of the  Queen  senililevis,  Plesechioceras  C h a r l o t t e Islands. yakounense,  61 taxa,  allocated to 27 genera,  Tetraspidoceras  pacificum  and  are  described.  Tetraspidoceras  Sunrisites  recognitum  are  i n t r o d u c e d as new species. T h e stratigraphic d i s t r i b u t i o n of ammonites, documented i n measured sections, is used to distinguish six successive assemblage  zones: the Canadensis Zone, "Coroniceras" Zone, A r n o u l d i Zone, V a r i a n s Zone,  Harbledownense Zone, and R e c o g n i t u m Zone. O f these o n l y the Canadensis Zone was established earlier, the r e m a i n i n g five  are  defined  here. These  zones  are  recognized throughout  the  islands and permit  high-  resolution biostratigraphic s u b d i v i s i o n of the upper part of Sandilands F o r m a t i o n and basal G h o s t Creek F o r m a t i o n . D a t i n g and correlation of the studied sections is achieved e m p l o y i n g this zonal scheme. T h e t o t a l thickness of uppermost  Hettangian  to lowermost  P l i e n s b a c h i a n s t r a t a i n sections  on K u n g a Island is  estimated at 385 m . C o m p a r i s o n of selected zones i n different sections indicates a moderate thickness increase to the  south. T h e contact  of the  Sandilands  F o r m a t i o n and the  overlying G h o s t Creek F o r m a t i o n is  diachronous, y o u n g i n g g r a d u a l l y to the south. T h e regional b i o c h r o n o l o g i c a l v a l i d i t y of the local zones is tested b y comparison w i t h the a m m o m i t e succession of other N o r t h A m e r i c a n S i n e m u r i a n localities. Besides the Taseko Lakes area and N e v a d a , the Q u e e n C h a r l o t t e Islands yield one of the most diverse a n d a b u n d a n t faunas of this age. A general agreement is found between the faunas of these key areas. T h u s the presented d a t a are of c r i t i c a l i m p o r t a n c e for constructing a regional biochronological scheme. Intercontinental  correlation  w i t h the  northwest  European  standard  zonation  is possible.  The  Canadensis Zone straddles the H e t t a n g i a n / S i n e m u r i a n boundary, w h i c h is best a p p r o x i m a t e d b y the first appearance of Badouxia  columbiae  and Metophioceras  spp. T h e position of the R e c o g n i t u m Zone at  the  S i n e m u r i a n / P l i e n s b a c h i a n b o u n d a r y has not been unambiguously decided; the majority of evidence points to its P l i e n s b a c h i a n affinities.  CONCLUSIONS  185  T h e ammonite fauna consists of t a x a w i t h pandemic, T e t h y a n , A t h a b a s c a n , East Pacific, or Pacific d i s t r i b u t i o n . P r o v i n c i a l i s m was not prominent b u t existed d u r i n g the S i n e m u r i a n time. T h e h i g h proportion of T e t h y a n forms lends support  to the  theory suggesting  a more southerly original paleolatitude for  W r a n g e l l i a . T h e d i s t r i b u t i o n p a t t e r n of T e t h y a n forms can be explained b y the early opening of the H i s p a n i c C o r r i d o r , proven to be i n existence by the P l i e n s b a c h i a n , although c o n v i n c i n g stratigraphic evidence from key areas between the  east-central  Pacific  and western T e t h y s is l a c k i n g . A l t e r n a t i v e l y , the  pantropic  d i s t r i b u t i o n model cannot be ruled out, although the faunal record from the eastern T e t h y s is inadequate to either prove or disprove it. T h e strong representation of A t h a b a s c a n a n d E a s t Pacific elements renders longdistance l o n g i t u d i n a l tectonic dislocation of W r a n g e l l i a unlikely. T h e paleoecology and t a p h o n o m y of ammonites, associated macrofauna, a n d trace fossils is used for paleoenvironmental  reconstruction.  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Sc. thesis, U n i v e r s i t y of B r i t i s h C o l u m b i a , 262  PVENTURI, F . 1978. A m m o n i t i della " C o r n i o l a " del M o n t e C a t r i a ( A p p e n i n o M a r c h i g i a n o ) . U n orizzonte fossilifero, a t t r i b u b i l e a l l ' m t e r v a l l o L o t h a r i n g i a n o sup. - C a r i x i a n o inf. B o l l e t i n o della Societ'a Paleontologica Italiano, 17: 98-117. WAHNER, F . 1882-1898. Beitrage zur K e n n t n i s der tieferen Zonen des unteren Lias i n den nord-ostlichen A l p e n , I-VIII. Beitrage zur Palaontologie u n d Geologie des Osterreich-Ungarns u n d Orients, V o l . 211, pp. 1-291. WALKER, R . G . 1984. T u r b i d i t e s and associated coarse clastic deposits. In Facies M o d e l s (2nd edition). Edited by R . G . W a l k e r . Geoscience C a n a d a , R e p r i n t Series 1, pp. 171-188. WANG, Y . and SMITH, P . L . 1986. S i n e m u r i a n ( E a r l y Jurassic) ammonite fauna from the G u a n g d o n g region of southern C h i n a . J o u r n a l of Paleontology, 60: 1075-1085. WESTERMANN, G . E . G . 1990. N e w developments i n ecology of Jurassic-Cretaceous ammonoids. In A t t i del II. Convegno Internazionale Fossili, E v o l u z i o n e , A m b i e n t e , Pergola, 1987. Edited by G . P a l l i n i et a l , pp. 459-478. WHITEAVES, J . F . 1883. O n the Lower Cretaceous rocks of B r i t i s h C o l u m b i a . R o y a l S o c i e t y . o f C a n a d a , Transactions, 1: 81-86. WHITEAVES, J . F . 1884. O n the fossils of the coal-bearing deposits of the Queen C h a r l o t t e Islands collected by D r . G . M . D a w s o n i n 1978. G e o l o g i c a l S u r v e y of C a n a d a , Mesozoic Fossils, V o l . 1, P a r t 3, pp. 191-262. WHITEAVES, J . F . 1889. T h e fossils of the Mesozoic rocks of B r i t i s h C o l u m b i a . Geological Survey of C a n a d a , C o n t r i b u t i o n s to C a n a d i a n Palaeontology, V o l . 1, P a r t 2, WlEDENMAYER, F . 1977. Die A m m o n i t e n des B e s a z i o - K a l k s ( P l i e n s b a c h i a n , Siidtessin). Schweizerische palaontologische A b h a n d l u n g e n , 98: 1-169.  REFERENCES  WlEDMANN, J . 1970. U b e r die U r s p r u n g der Neoammonoideen. geologicae Helvetiae, 63: 932-1020.  201  Das P r o b l e m einer Typogenese.  Y O L E , R . W , and IRVING, E . 1980. Displacement of V a n c o u v e r Island: paleomagnetic K a r m u t s e n F o r m a t i o n . C a n a d i a n J o u r n a l of E a r t h Sciences, 17: 1210-1288.  Eclogae  evidence f r o m the  ZlEGLER, B . 1967. A m m o n i t e s Okologie a m Beispiel des Oberjura. Geologische R u n d s c h a u , 56: 439-464.  APPENDIX  202  APPENDIX FOSSIL LOCALITIES SECTION A K e n n e c o t t P o i n t ; from a boulder field to the n o r t h up to the contact w i t h the Masset F o r m a t i o n ; lat. 5 3 ° 5 4 ' 2 0 " N , long. 1 3 3 ° 0 9 ' 1 0 " W . LEVEL  GSC  FIELD  NUMBER  NUMBER  1 2  C-159259 C-159258  606C 606B  4 5 6  C-159257 C-159255 C-159254  606A 605D 605C  SECTION B K e n n e c o t t P o i n t ; n o r t h of a boulder field; lat. 5 3 ° 5 4 ' 2 5 " N , long. 1 3 3 ° 0 9 ' 0 5 " W . LEVEL  GSC NUMBER  FIELD NUMBER  LEVEL  GSC NUMBER  FIELD NUMBER  1 2 3 4 5 6  C-156423 C-159266 C-159265 C-159264 C-159263 C-156424  622A 608A 607E 607D 607C 622B  6 7 8 9 9  C-159262 C-159261 C-159260 C-156425 C-156426  607B 607A 606D 622C 623A  SECTION C K e n n e c o t t P o i n t ; n o r t h of Section B and east of Section D separated b y a strike-slip fault; lat. 5 3 ° 5 4 ' 3 0 " N , long. 1 3 3 ° 0 9 ' 0 0 " W . LEVEL  1  GSC  FIELD  NUMBER  NUMBER  C-156428  623C  SECTION D K e n n e c o t t P o i n t ; west of Section C , on the 133°09'20"W.  opposite  side of a strike-slip fault; lat. 5 3 ° 5 4 ' 3 0 " N , long.  APPENDIX  LEVEL  1 1 2 3 4 5 6 7 7  203  GSC NUMBER  FIELD NUMBER  LEVEL  C-159251 C-159291  604A 610J  C-159290 C-159289 C-159288 C-159287  8 9 10 11 12 13 14  C-159252 C-159286 C-175211 C-159285 C-159284 C-159283 C-159282 C-159281 C-159280 C-159279  GSC NUMBER  FIELD  15  C-159278  6101 610H 610G  16 17 18 18  C-159292 C-159277 C-159276  6091 610K  C-156953  609H 609G 13-3TD  610F 604B 610E 25A  19 20 20 21  C-159275 C-159274 C-156952 C-159273  609F 609E 13-2TD 609D  610D 610C 610B 610A  22 23 24 25  C-156421 C-159272 C-159271 C-159269  609L 609K 609J  25 26 27 27  C-159270 C-159268 C-159267  618A 609C 609B 608D 609A  C-156980  NUMBI  608C 608B 20-1TD  SECTION E K e n n e c o t t P o i n t ; short section between Sections C and F , b o u n d e d b y two east-west t r e n d i n g n o r m a l faults; lat. 5 3 ° 5 4 ' 3 5 " N , long. 1 3 3 ° 0 9 ' 0 0 " W . SECTION F K e n n e c o t t P o i n t ; n o r t h of Section E , ends at a boulder field a r o u n d a large boulder b u t c o n t i n u a t i o n traceable b y a marker bed further northwest, offset several meters by a strike-slip fault; lat. 5 3 ° 5 4 ' 4 5 " N , long. 133°09'15"W. LEVEL  SECTION  GSC NUMBER  FIELD NUMBER  LEVEL  GSC NUMBER  FIELD NUMBER  C-156420 C-175219 C-156419 C-156418 C-156417 C-156416 C-175218 C-156406 C-156414 C-175216 C-156405 C-156404  617E 26C 617D 617C 617B 617A 26B  10 11 12 13 14 15 16 17 18 19 20  C-156403 C-156402 C-156401 C-159300 C-159299 C-159298 C-159297 C-159296 C-159295 C-159294 C-159293  611K 611J 6111 611H 611G 611F 611E 611D  611N 614C 25F 611M 611L  611C 611B 611A  G  K e n n e c o t t P o i n t ; n o r t h of a boulder field around a large boulder and Section F , base of section is a bed w i t h a b u n d a n t Chondrites; lat. 5 3 ° 5 4 ' 5 0 " N , long. 1 3 3 ° 0 9 ' 0 5 " W .  APPENDIX  LEVEL  13 14  204  GSC  FIELD  NUMBER  NUMBER  C-175202 C-175201  24B 24A  SECTION H Y a k o u n R i v e r , west bank, over 300 m nearly continuous exposure, p a r t l y submerged at higher water levels; lat. 5 3 ° 2 4 ' 4 0 " N , long. 1 3 2 ° 1 6 ' 2 0 " . LEVEL  GSC NUMBER  FIELD NUMBER  LEVEL  GSC NUMBER  FIELI NUM1  1 2 3  C-159401 C-159402 C-159403  YL1 YL2 YL3  24 25  C-159422 C-159423 C-159424  YL22 YL23 YL24  4 5 6 7 8 9 10 11 12 13 14 15 16 17  C-159404 C-159405 C-159406 C-175243 C-159407 C-159408 C-159409 C-159410 C-175244 C-159411 C-159412 C-159413 C-159414 C-159415 C-159416 C-159417 C-159418 C-159419 C-159420 C-159421  YL4 YL5 YL6 2A YL7 YL8 YL9 YL10 2B YL11 YL12 YL13 YL14 YL15 YL16 YL17 YL18 YL19 YL20 YL21  C-159425 C-159426 C-159427 C-159428 C-159429 C-159430 C-159431 ' C-159432 C-159433 C-159434 C-159435 C-159436 C-159437 C-159438  YL25 YL26 YL27 YL28 YL29 YL30 YL31 YL32 YL33 YL34 YL35 YL36 YL37 YL38 YL39 YL41 YL46 YL47 YL48 YL49 YL50  18 19 20 21 22 23  26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 43 4849 50 51 52  C-159439 C-159440 C-159442 C-159443 C-159444 C-159445 C-159446  SECTION I Y a k o u n R i v e r , west bank, u p s t r e a m from Section H separated by a covered i n t e r v a l at the sharp bend of river; lat. 5 3 ° 2 4 ' 2 0 " N , long. 1 3 2 ° 1 6 ' 2 0 " .  APPENDIX  LEVEL  205  GSC NUMBER  FIELD NUMBER YL101 YL102 YL103 YL104  1  C-177616  2 3 4 5  C-177617  6 7  C-177621 C-177622  C-177618 C-177619 C-177620  YL105 YL106 YL107  SECTION J Y a k o u n R i v e r , east bank, opposite of Section H , largely d u p l i c a t i n g that; lat. 5 3 ° 2 4 ' 4 0 " N , long. 1 3 2 ° 1 6 ' 2 0 " .  SECTION K Q u a r r y on Queen  Charlotte  Main  logging road  at  K m 26; collection made b y R . B . M c F a r l a n e  (see  M C F A R L A N E , 1988); lat. 5 3 ° 2 4 ' 4 0 " N , long. 1 3 3 ° 1 8 ' 1 5 " W .  SECTION L R o a d c u t on G h o s t M a i n logging road; lat. 5 3 ° 2 5 ' 1 0 " N , long. 1 3 3 ° 1 8 ' 0 5 " W .  LEVEL  1 2 3 4 5 7  GSC NUMBER  C-175231 C-175232 C-175233 C-175234 C-175235 C-175236  FIELD NUMBER  1A1 1A2 1A3 1A4 1A5 1A7  LEVEL  GSC NUMBER  FIELD NUMB]  8 9 10  C-175237 C-175238 C-175239 C-175240 C-175241  1A8 1A9 1A10 1A11 1A12  11 12  SECTION M M a u d e Island, south shore, west of F a n n i n B a y , westward TIPPER, 1985; lat. 5 3 ° 1 1 ' 5 0 " N , long. 1 3 2 ° 0 3 ' 0 5 " W .  c o n t i n u a t i o n of Section 8 of CAMERON a n d  APPENDIX  LEVEL  1 2 3 4 5  206  GSC NUMBER  FIELD NUMBER  LEVEL  GSC NUMBER  C-175247 C-175246 C-175226 C-175227 C-175228  4E1 4D1 28C1 28C2 28C3  6 7 8 9 float  C-175225 C-175224 C-175223 C-175222 C-175248  FIELD NUMBER 28A4 28A3 28A2 28A1 4F1  SECTION N Sandilands Island, southeast shore, n o r t h of a s m a l l inlet; lat. 5 3 ° 1 0 ' 2 0 " N , long. 1 3 2 ° 0 5 ' 1 0 " W .  SECTION O R o a d c u t on A l l i f o r d R o a d a t " K m 2, south of Whiteaves B a y ; lat. 5 3 ° 1 1 ' 0 0 " N , long. 1 3 2 ° 0 1 ' 0 5 " W .  LEVEL  GSC NUMBER  FIELD NUMBER  1  C-175229  29A  2  C-175230  29B  SECTION P Q u a r r y on logging road W 100, east of T a s u Sound; lat. 5 2 ° 4 8 ' 1 0 " N , long. 1 3 2 ° 0 1 ' 2 0 " W . LEVEL 1 2 3 4 5  GSC NUMBER  FIELD NUMBER  C-156438 C-156439 C-156440 C-156441 C-156442  724A 724B 724C 724D 724E  LEVEL 6 7 float float  GSC NUMBER C-156443 C-156444 C-156445 C-156432  FIELD NUMBER 724F 724G 724FL 717B  SECTION Q Q u a r r y on logging road W 160, east of T a s u S o u n d ; lat. 5 2 ° 4 8 ' 0 5 " N , long. 1 3 2 ° 0 1 ' 2 5 " W .  LEVEL  GSC NUMBER  1 2 3 float float float  C-156433 C-156434 C-156435 C-156436 C-156437 C-156431  FIELD NUMBER 722A 722B 722C 722LF 722UF 717A  APPENDIX  SECTION  207  R  R o a d c u t on M e t r i c M a i n logging road, southeast of T a s u S o u n d , n o r t h of B a r r i e r B a y , collection made by S. T A I T E ; lat. 5 2 ° 4 7 ' 4 0 " N , long. 1 3 1 ° 5 7 ' 3 5 " W .  LEVEL  GSC NUMBER  FIELD NUMBER ST90-06  1 SECTION  S  K u n g a Island, northeast shore; lat. 5 2 ° 4 6 ' 2 5 " N , long. 1 3 1 ° 3 3 ' 1 0 " W LEVEL .  GSC NUMBER  FIELD NUMBER  LEVEL  28 29 30 31 32 33 34 35 36 37 38 38 39 40 41 42 43 44  C-177278 C-177279  45 46 47 48 49 50 51 52  C-177296 C-177297 C-177298 C-177299 C-177300 C-177302 C-177301 C-177303  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18  C-177251 C-177252 C-177253 C-177254 " C-177255 C-177256 C-177257 C-177258 C-177259 C-177260 C-177261 C-177262 C-177263 C-177264 C-177265 C-177266 C-177267 C-177268  704A ( = K 4 A ) 704B ( = K 4 B )  19 20 21 22 23 24 25 26 27  C-177269 C-177270 C-177271 C-177272 C-177273 C-177274 C-177275 C-177276 C-177277  708J ( = K 8 J ) 708K ( = K 8 K ) 708L ( = K 8 L ) 708M ( = K 8 M ) 708N ( = K 8 N ) 708O ( = K 8 0 ) 708P ( = K 8 P )  704C 704D 704E 704F 704G  (=K4C) (=K4D) (=K4E) (=K4F) (=K4G)  704H ( = K 4 H ) 708A ( = K 8 A ) 708B ( = K 8 B ) 708C ( = K 8 C ) 708D ( = K 8 D ) 708E ( = K 8 E ) 708F ( = K 8 F ) 708G ( = K 8 G ) 708H ( = K 8 H ) ' 7081 ( = K 8 I ) 708U ( = K 8 U )  708Q ( = K 8 Q ) 708R ( = K 8 R )  GSC NUMBER  C-177280 C-177281 C-177282 C-177283 C-177285 C-177286 C-177284 C-177287 C-177288 C-177289 C-177290 C-177291 C-177292 C-177293 C-177294 C-177295  SECTION T K u n g a Island, southeast shore; lat. 5 2 ° 4 5 ' 4 0 " N , long. 1 3 1 ° 3 3 ' 0 0 " W .  FIELD NUMBER 708S 708T 709A 709B  (=K8S) (=K8T) (=K9A) (=K9B)  709C ( = K 9 C ) 709D ( = K 9 D ) 709F ( = K 9 F ) 709G ( = K 9 G ) 709E ( = K 9 E ) 709H ( = K 9 H ) 7091 ( = K 9 I ) 709J ( = K 9 J ) 709K ( = K 9 K ) 709L ( = K 9 L ) 709M ( = K 9 M ) 709N ( = K 9 N ) 709O ( = K 9 0 ) 709P ( = K 9 P ) 709Q ( = K 9 Q ) 709R ( = K 9 R ) 709S ( = K 9 S ) 709T ( = K 9 T ) 709U ( = K 9 U ) 709W ( = K 9 W ) 709V ( = K 9 V ) 709Z ( = K 9 Z )  208  APPENDIX  LEVEL  1 2 3 4 4 5 6 7 ' 8 9 10 11 12 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32  GSC NUMBER C-177304 C-177305 C-177306 C-177307 C-177309 C-177310 C-177311 C-177308 C-177312 C-177313 C-177314 C-177315 C-177316 C-177317 C-177318 C-177319 C-177320 C-177321 C-177322 C-177323 C-177324 C-177325 C-177326 C-177327 C-177328 C-177329 C-177330 C-177331 C-177332 C-177333 C-177334 C-177335 C-177336 C-177337  FIELD NUMBER  LEVEL  705A ( ==K5A) 705B (== K5B) 705C (=: K 5 C ) 705D (-= K5D) 705F (== K5F) 705G 0=K5G) 705H ( ==K5H) 705E (==K5E) 7051 (= K5I) 705J (=:K5J) 705K (== K 5 K ) 705L (=:K5L) 705M (:=K5M) 705N (==K5N) 705O (-=K50) 705P (==K5P) 705Q (==K5Q) 705R 0=K5R) 705S (=:K5S) 706A ( ==K6A) 706B (--=K6B) 706C ( ==K6C) 706D {--=K6D) 706E (==K6E) 706F (==K6F) 706G (:=K6G) 706H (-=K6H) 7061 (= K6I) 706J (=:K6J) 706K (:=K6K) 706L (== K6L) 706M ( = K 6 M ) 706N (:=K6N) 706O (:=K6Q)  33 34 35 36 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 52 53 54 55 56 57 58 58 59 60 61 62 63 64 65 66  GSC NUMBER C-177339 C-177338 C-177340 C-177341 C-177342 C-177343 C-177344 C-177345 C-177346 C-177347 C-177348 C-177349 C-177350 C-177601 C-177602 C-177603 C-177604 C-177605 C-177606 — — — —  C-177608 —  C-177609 —  C-177610 C-177611 — —  C-177612 C-177613 C-177614 C-177615  FIELD NUMBER 706Q (== K6Q) 706P (=:K6P) 706R (==K6R) 706S (=:K6S) 706SZ ( =K6SZ) 706T (==K6T) 706U (=r K 6 U ) 707A (==K7A) 707B (==K7B) 707C (==K7C) 707D (==K7D) 707E (==K7E) 707F (==K7F) 707G (== K7G) 707GY ( = K 7 G Y ) 707H 0=K7H) 7071 (= K7I) 707J (=:K7J) 707K ( ==K7K) PLS25 PLS24 PLS23 PLS22 707M (:= K 7 M ) PLS21 707N (:=K7N) PLS20 707O (:=K70) 707P (==K7P) PLS19 PLS18 707Q (:=K7Q) 707R (:=K7R) 707S (==K7S) 707T (:=K7T)  209  PLATES  210 EXPLANATION OF PLATE 1 (Figures n a t u r a l size unless otherwise indicated) ( E n d of phragmocone i n d i c a t e d w i t h an arrowhead)  F i g u r e 1-2  F i g u r e 3, 5-7  Juraphyllites cf. transylvanicus  (HAUER)  1 L a t e r a l view of compressed i n t e r n a l Section P , ex situ, p r o b a b l y A r n o u l d i Zone.  mould.  Specimen  717B/1,  2 L a t e r a l view of compressed i n t e r n a l Section T , Level 7, "Coroniceras" Zone.  mould.  Specimen  705E/1,  Juraphyllites aff. nardii  (MENEGHINI)  3 [Macroconch] L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 4 7 / 8 , Section H , Level 49, R e c o g n i t u m Zone. 5 [microconch] L a t e r a l view of i n t e r n a l m o u l d . Specimen P L S 8 9 - 2 1 / 1 , Section T , Level 57, R e c o g n i t u m Zone. 6 [microconch] L a t e r a l view of i n t e r n a l m o u l d . Specimen P L S 8 9 - 2 1 / 2 , Section T , Level 57, R e c o g n i t u m Zone. 7 [Macroconch] V e n t r a l impression. Level 49, R e c o g n i t u m Zone. Figure 4  Specimen  Y L 4 7 / 9 , Section H ,  Phylloceras sp. L a t e r a l view of internal m o u l d . . S p e c i m e n C-156980/21, Section D , Level 27, Canadensis Zone, x2.  Figure 8  Juraphyllites cf. limatus ( R O S E N B E R G , 1909) L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 7 2 4 Q F / 3 , Section P , ex situ, probably A r n o u l d i Zone.  Figure 9  Juraphyllites sp. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 6 0 8 B / 8 , Section D , Level 24, Canadensis Zone.  F i g u r e 10, 12  Lytoceras spp. 10 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 6 0 6 B , Section A , Level 2, Canadensis Zone. 12 L a t e r a l view of compressed internal Section F , Level 13, Canadensis Zone.  F i g u r e 11  mould.  Specimen  611H/2,  Lytoceras sp. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 6 0 9 H / 9 , Section D , Level 17, Canadensis Zone  212 EXPLANATION OF PLATE 2 (Figures n a t u r a l size unless otherwise indicated)  Figure 1,5  Ectocentrites ? sp. 1  L a t e r a l view of compressed  internal  Specimen 611G, Section F , L e v e l 14, Canadensis 5  L a t e r a l view of compressed  internal  mould  mould  Specimen C-156980, Section D , Level 27, Canadensis  Figure 2  of w h o r l  fragment.  of w h o r l  fragment.  Zone.  Zone.  Tragolytoceras ? sp. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 1 0 / 1 , Section H , Level 12, A r n o u l d i Zone.  Figure 3, 7-8  Eolytoceras ? guexi ? T A Y L O R 3 L a t e r a l view of compressed Section D , Level 2, Canadensis Zone  internal  7 L a t e r a l view of compressed internal Section F , Level 14, Canadensis Zone.  mould.  mould.  Specimen  Specimen  6101/3,  611G/3,  8 L a t e x cast of external m o u l d . Specimen 2 5 A / 1 , Section D , Level 7, Canadensis Zone.  Figure 4  Adnethiceras cf. adnethicum ( H A U E R ) L a t e x cast of external A r n o u l d i Zone.  Figure 6  m o u l d . Specimen  706O/2,  Section  T , L e v e l 32,  Audaxlytoceras aff. audax ( M E N E G H I N l ) L a t e r a l view of compressed i n t e r n a l m o u l d . S p e c i m e n 7 2 4 A / 1 , Section P , Level 1, A r n o u l d i Zone.  214 EXPLANATION OF PLATE 3 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1, 4  Eolytoceras tasekoi F R E B O L D 1 L a t e r a l view of weathered Section D , Level 3, Canadensis Zone.  F i g u r e 2, 3  internal  mould.  Specimen  610H/2,  4 L a t e r a l view of compressed i n t e r n a l Section D , Level 10, Canadensis Zone.  mould.  Specimen  610B/1,  mould.  Specimen  610A/6,  Sulciferites cf. trapezoidalis  (SOWERBY)  2 L a t e r a l view of compressed i n t e r n a l Section D , Level 11, Canadensis Zone.  4 L a t e x cast o f external m o u l d of v e n t r a l 6 0 9 D / 1 1 , Section D , Level 21, Canadensis Zone. Figure 5  Angulaticeras spezianum  impression.  Specimen  (CANAVARl)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 7 2 4 D / 1 , Section P , Level 4, A r n o u l d i Zone. Figure 6  Sulciferites ? sp. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 7 0 4 F / 7 , Section S, Level 6, "Coroniceras" Zone.  F i g u r e 7, 10  Badouxia cf. occidentalis  (FREBOLD)  7 L a t e r a l view of compressed Section F , Level 14, Canadensis Zone. 10 L a t e r a l view of compressed Section F , Level 1, Canadensis Zone. Figure 8  Sulciferites marmoreus  internal  internal  mould.  mould.  Specimen 6 1 1 G ,  Specimen  617E/6,  (OPPEL)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 6 0 9 E / 4 , Section D , Level 20, Canadensis Zone. Figure 9  Angulaticeras cf. ventricosum  (SOWERBY)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Level 3, Canadensis Zone.  6 1 0 H , Section D ,  216 E X P L A N A T I O N O FP L A T E 4 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1-2  Badouxia oregonensis T A Y L O R 1 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 617E, Section F , Level 1, Canadensis Zone. 2 L a t e r a l view of latex cast of external Section D , Level 1, Canadensis Zone.  Figure 3  Badouxia columbiae  m o u l d . Specimen  (FREBOLD)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen L e v e l 21, Canadensis Zone. Figure 4  604A/5,  609E, Section D ,  Badouxia aff. occidentalis ( F R E B O L D ) L a t e r a l view o f compressed i n t e r n a l m o u l d . Specimen 6 1 4 C / 1 , Section G , L e v e l 28, Canadensis Zone.  Figure 5  Badouxia ? s p . L a t e r a l view of latex cast of external m o u l d . Specimen 6 1 1 N / 2 , Section F , Level 6, Canadensis Zone.  218 EXPLANATION OF PLATE 5 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1-2, 6  Badouxia  canadensis  (FREBOLD)  1 L a t e r a l view of compressed Section F , Level 14, Canadensis Zone.  internal  mould.  Specimen  611G,  2 L a t e r a l view of compressed Section D , Level 8, Canadensis Zone.  internal  mould.  Specimen  610D,  6 L a t e r a l view of i n t e r n a l m o u l d of juvenile i n d i v i d u a l . Specimen 610E, Section D , L e v e l 7, Canadensis Zone. F i g u r e 3-4, 8  Badouxia  columbiae  (FREBOLD)  3 L a t e r a l view of compressed i n t e r n a l Section D , Level 19, Canadensis Zone.  mould.  Specimen  609F/1,  4 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 606C, Section A , Level 1, Canadensis Zone. 8 L a t e r a l view of compressed Section D , Level 22, Canadensis Zone. F i g u r e 5, 9  Sunrisites  senililevis  internal  mould.  Specimen  618A,  n. sp.  5 P a r a t y p e . L a t e r a l view of latex cast of external m o u l d . Section F , Level 6, Canadensis Zone. 9 H o l o t y p e . I n t e r n a l m o u l d . Specimen C-143327/c, Castle Pass near T y a u g h t o n Creek, T a s e k o Lakes area, G S C locality C-143327, Canadensis Zone. Figure 7  Vermiceras  sp.  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen C-156980, Section D , L e v e l 27, Canadensis Zone.  220 E X P L A N A T I O N OF P L A T E 6 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1, 5  Vermiceras ex gr. coregonense  (SOWERBY)  1 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 610C, Section D , Level 9, Canadensis Zone. 5 L a t e r a l view of compressed Section D , L e v e l 17, Canadensis Zone. Figure 2  Vermiceras cf. supraspiratum  internal  mould.  Specimen  609H,  (WAEHNER)  L a t e r a l view o f compressed internal m o u l d . Specimen 6 0 4 A / 4 , Section D , Level 1, Canadensis Zone. F i g u r e 3, 6  Metophioceras aff. roiarium ( B U C K M A N ) 3  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 607E, Section  B , Level 3, Canadensis Zone. 6 L a t e r a l v i e w of compressed i n t e r n a l m o u l d . Specimen Section D , Level 27, Canadensis Zone. F i g u r e 4, 8  C-156980,  Vermiceras sp. 4 V e n t r a l v i e w of i n t e r n a l m o u l d o f unusually embedded i n d i v i d u a l . Specimen C-156980, Section D , Level 27, Canadensis Zone. 8 L a t e r a l view of i n t e r n a l Level 27, Canadensis Zone.  Figure 7  m o u l d . Specimen  C-156980, Section D ,  Coroniceras ? sp. L a t e r a l view of compressed i n t e r n a l Level 6, "Coroniceras" Zone.  m o u l d . Specimen  607C, Section B ,  222 EXPLANATION OF PLATE 7 (Figures n a t u r a l size unless otherwise  Figure 1  Metophioceras cf. rursicostatum  indicated)  (FREBOLD)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen C-156980, Section D , L e v e l 27, Canadensis Zone. Figure 2  Arnioceras miserabile  (QUENSTEDT)  L a t e r a l view of compressed  i n t e r n a l m o u l d . Specimen 2 A / 1 , Section H ,  Level 7, A r n o u l d i Zone. Figure 3  Arnioceras cf. densicosta ( Q U E N S T E D T ) 7 0 6 E / 1 , Section T , Level 22, A r n o u l d i Z o n e . L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen  Figure 4  Metophioceras spp. L a t e r a l view of compressed Level 5, Canadensis Zone.  Figure 5  i n t e r n a l m o u l d . Specimen 6 0 5 D / 2 , Section A ,  Arnioceras sp. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 622B, Section B , Level 6, "Coroniceras" Zone.  Figure 6  Arietitinae gen. et sp. indet. L a t e r a l view of compressed i n t e r n a l m o u l d of w h o r l fragment. 607B, Section B , Level 6, "Coroniceras" Zone.  Specimen  224 EXPLANATION OF PLATE 8 (Figures n a t u r a l size unless otherwise indicated)  Figure 1  Arnioceras  c f . oppeli G U E R I N - F R A N I A T T E  L a t e r a l view o f compressed internal m o u l d . Specimen Level 38, V a r i a n s Zone. Figure 2  Arnioceras  K 9 I / 1 , Section S,  e x g r . mendax F U C I N I  L a t e r a l view of compressed internal m o u l d . Specimen K 6 L / 9 , Section T , L e v e l 29, A r n o u l d i Zone. Figure 3  Arnioceras  arnouldi  (DUMORTIER)  L a t e r a l view of internal p r o b a b l y A r n o u l d i Zone.  mould.  Specimen  717A, Section  Q , ex situ,  226 E X P L A N A T I O N OF P L A T E 9 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1, 2  Arnioceras  arnouldi ( D U M O R T I E R )  1 V e n t r a l view of internal m o u l d of w h o r l fragment. Specimen S T 9 0 06, Section R , A r n o u l d i Zone. 2 L a t e r a l view of internal m o u l d of w h o r l fragment. Same specimen as F i g u r e 1. F i g u r e 3, 6  F i g u r e 4-5  Arnioceras  cf. speciosum F U C I N I  3 L a t e r a l view of compressed Section T , Level 34, A r n o u l d i Zone.  internal  6 L a t e r a l view of compressed Section T , Level 26, A r n o u l d i Zone.  internal  Hypasteroceras  mould.  mould.  Specimen  Specimen  706P/1,  7061/1,  ? sp.  4 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Section I, Level 1, V a r i a n s Zone.  YL101/4,  5 L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Section I, Level 1, V a r i a n s Zone.  YL101/3,  228 E X P L A N A T I O N O F P L A T E 10 (Figures n a t u r a l size unless otherwise indicated) ( E n d of phragmocone indicated w i t h an arrowhead)  F i g u r e 1-2  Arnioceras e x g r . ceratitoides  (QUENSTEDT)  1 L a t e r a l view of compressed Section H , Level.9, A r n o u l d i Zone.  internal  mould.  Specimen  YL8/3,  2 L a t e r a l view of internal m o u l d . Specimen Y L 1 1 / 7 , Section H , Level 13, V a r i a n s Zone. F i g u r e 3, 7-8  Epophioceras aff. carinatum S P A T H 3  L a t e r a l view of compressed  internal  mould.  Specimen  YL11/2,  Section H , Level 13, V a r i a n s Zone. 7 L a t e r a l view of inner whorls of i n t e r n a l m o u l d . Specimen Y L 1 1 / 2 1 , secH, Level 13, V a r i a n s Zone, x2. 8 L a t e r a l view of compressed Section H , Level 13, V a r i a n s Zone. F i g u r e 4, 6  Asteroceras  internal  mould.  Specimen  YL11/3,  c f . varians F U C I N I  4 L a t e r a l view of i n t e r n a l m o u l d of w h o r l fragment. Specimen Y L 1 1 , Section H , L e v e l 13, V a r i a n s Zone. 6 L a t e r a l view of compressed i n t e r n a l Section I, L e v e l 6, V a r i a n s Zone. Figure 5  Asteroceras  m o u l d . Specimen  YL106/1,  aff. margarita ( P A R O N A )  L a t e r a l view of latex cast of external m o u l d . Specimen 7 0 9 E / 1 , Section S, Level 36, V a r i a n s Zone. Figure 9  Asteroceras  saltriense ? ( P A R O N A )  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 7 1 5 A , Section M , ex s i t u , p r o b a b l y V a r i a n s Zone.  230 E X P L A N A T I O N O F P L A T E 11 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1-4  Plesechioceras  ? harbledownense ( C R I C K M A Y )  1 Holotype of Melanhippites harbledownense CRICKMAY, 1928. L a t e r a l view of plaster cast of external m o u l d . G S C T y p e N o . 25679, H a r b l e d o w n Island. 2 L a t e r a l view of latex cast of external m o u l d o f inner Specimen 7 0 7 H / 1 0 , Section T , L e v e l 47, Harbledownense Zone.  whorls.  3 P a r a t y p e N o . 2 of Melanhippites harbledownense CRICKMAY, 1928. L a t e r a l view of latex cast of external m o u l d . G S C T y p e N o . 25681, H a r b l e d o w n Island. 4 L a t e r a l view of compressed i n t e r n a l Section H , Level 22, Harbledownense Zone. Figure 5  Plesechioceras  m o u l d . Specimen  YL20/7,  ? harbledownense ? ( C R I C K M A Y )  P a r a t y p e N o . 1 of Melanhippites harbledownense CRICKMAY, 1928 (Designated as neotype b y GETTY, 1973). L a t e r a l view of compressed internal m o u l d . G S C T y p e N o . 25680, H a r b l e d o w n Island.  232 E X P L A N A T I O N O F P L A T E 12 (Figures n a t u r a l size unless otherwise indicated)  F i g u r e 1-2,  5, 7  Plesechioceras 1  yakounense  n sp.  P a r a t y p e . L a t e r a l view of compressed internal  mould.  Specimen  mould.  Specimen  5 P a r a t y p e . L a t e r a l view of compressed i n t e r n a l m o u l d . Y L 1 4 / 3 2 , Section H , L e v e l 16, Harbledownense Zone.  Specimen  Y L 1 5 / 1 1 , Section H , Level 17, Harbledownense 2  H o l o t y p e . L a t e r a l view of compressed i n t e r n a l  Y L 1 4 / 3 0 , Section H , Level 16, Harbledownense  7  Zone.  Zone.  L a t e r a l view w i t h fragment of venter of compressed i n t e r n a l m o u l d .  Specimen Y L 1 0 6 / f l , Section I, ex s i t u , p r o b a b l y Harbledownense F i g u r e 3-4  F i g u r e 6, 8  Paltechioceras  Zone.  aff. boehmi ( H U G )  3 L a t e r a l view of compressed -internal Section H , Level 32, Harbledownense Zone.  mould. Specimen  Y130/31,  4 L a t e r a l view of compressed internal Section H , Level 33, Harbledownense Zone.  mould. Specimen  Y131/22,  6 L a t e r a l view of compressed i n t e r n a l m o u l d . S p e c i m e n Section H , Level 24, Harbledownense Zone.  YL22/16,  8 L a t e r a l view of compressed internal m o u l d . Specimen Section H , Level 24, Harbledownense Zone.  YL23/51,  Plesechioceras  ? c f . aklavikense  (FREBOLD)  234 E X P L A N A T I O N O F P L A T E 13 (Figures n a t u r a l size unless otherwise indicated) ( E n d of phragmocone indicated w i t h an arrowhead)  Figure 1  Paltechioceras  cf. romanicum  (TJHLIG)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 2 9 / 3 , Section H , Level 31, Harbledownense F i g u r e 2-3  Figure 4  Gleviceras  cf. subguibalianum  Zone. (PlA)  2 L a t e r a l view of compressed i n t e r n a l Section H , Level 17, Harbledownense Zone.  m o u l d . Specimen  YL15/10,  3 L a t e r a l view of compressed i n t e r n a l Section H , Level 17, Harbledownense Zone.  m o u l d . Specimen  YL15/12,  Radstockiceras  ex gr. numismale  (OPPEL)  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Level 7, R e c o g n i t u m Zone. Figure 5  Paltechioceras  cf. rothpletzi  2 8 A 3 , Section M , 1  (BOSE)  L a t e r a l view of compressed i n t e r n a l m o u l d . S p e c i m e n Y L 3 2 / 2 , Section H , Level 34, Harbledownense Zone. Figure 6  Paltechioceras  sp.  L a t e r a l view of i n t e r n a l m o u l d w i t h some shell m a t e r i a l . Specimen Section H , Level 35, Harbledownense Zone.  YL33/1,  236 E X P L A N A T I O N O F P L A T E 14 (Figures n a t u r a l size unless otherwise indicated) ( E n d o f phragmocone indicated w i t h an arrowhead)  Figure 1, 6  Crucilobiceras ? sp. 1 L a t e r a l view of compressed Section L , Level 4, R e c o g n i t u m Zone.  internal  mould.  Specimen  6 L a t e r a l view of compressed i n t e r n a l m o u l d of w h o r l Specimen Y L 4 8 / 1 8 , Section H , Level 50, R e c o g n i t u m Zone. Figure 2  1A4/1,  fragment.  Oxynoticeras cf. simpsoni ( S I M P S O N ) L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 1 4 / 1 1 , Section H , Level 16, Harbledownense Zone.  Figure 3  Posidonotis semiplicata  (HYATT)  Impressions of shells o n b e d d i n g plane. Specimen Y L 4 6 / 2 , Section H , Level 48, R e c o g n i t u m Zone. Figure 4  Tetraspidoceras pacificum n. sp. P a r a t y p e . L a t e r a l view of latex cast of external m o u l d . Specimen Section T , L e v e l 36, Harbledownense Zone.  Figure 5  706S/1,  Oxynoticeratidae gen. et sp. indet. L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 4 8 / 1 5 , Section H , Level 50, R e c o g n i t u m Zone.  Figure 7  Tetraspidoceras sp. L a t e r a l view of compressed i n t e r n a l m o u l d of w h o r l fragment. Y L 1 5 / 1 , Section H , Level 17, Harbledownense Zone.  Figure 8  Tetraspidoceras  Specimen  recognitum n. sp.  [microconh] H o l o t y p e . L a t e r a l view of i n t e r n a l m o u l d . Specimen 2 8 A 2 / 1 , Section M , L e v e l 8, R e c o g n i t u m Zone. B o d y chamber slightly longer t h a n one w h o r l .  238 E X P L A N A T I O N O F P L A T E 15 (Figures n a t u r a l size unless otherwise  Figure 1, 4  indicated)  Tetraspidoceras recognitum n. sp. 1 [microconch] P a r a t y p e . L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 4 8 / 1 0 , Section H , L e v e l 50, R e c o g n i t u m Zone. 4  [Macroconch] P a r a t y p e . L a t e r a l view of compressed i n t e r n a l m o u l d .  Specimen 93749, Section M , ex s i t u , p r o b a b l y R e c o g n i t u m Zone, x0.66. B o d y chamber slightly longer t h a n one w h o r l .  Figure 2  Posidonotis semiplicata (HYATT) Impressions of shells on b e d d i n g plane. Specimen 2 8 A 4 / 1 , Section M , Level 6, R e c o g n i t u m Zone.  Figure 3  Crucilobiceras  ? sp.  L a t e r a l view of i n t e r n a l m o u l d of w h o r l fragment. Section H , L e v e l 43, R e c o g n i t u m Zone.  Specimen  YL41/1,  P L A T E 15  239  240 E X P L A N A T I O N O F P L A T E 16 (Figures n a t u r a l size unless otherwise indicated)  Figure 1  Phricodoceras  sp.  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen 7 0 7 S / 1 , Section T , Level 65, I m l a y i Zone.  Figure 2  Fish remains L a t e r a l view. Specimen 609D, Section D , Level 21, Canadensis Zone.  Figure 3  Miltoceras  sp.  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 4 9 / 1 , Section H , Level 51, I m l a y i Zone.  Figure 4  Gemmellaroceras  sp.  L a t e r a l view of compressed i n t e r n a l m o u l d . Specimen Y L 4 9 / 1 , Level 51, I m l a y i Zone. Figure 5  Alsatites  cf. proaries  Section H ,  (NEUMAYR)  L a t e r a l view of compressed i n t e r n a l m o u l d w i t h some shell Specimen 2 4 C / 1 , Section G , Level 10, U p p e r H e t t a n g i a n .  material.  E X P L A N A T I O N O F P L A T E 17 (Figures n a t u r a l size unless otherwise  Figure 1, 5  Camptonectes  (Camptochlamys)  1 Left valve, Harbledownense Zone.  Figure 2, 11  Otapiria  sp.  Specimen  5 Right valve, Harbledownense Zone.  indicated)  Specimen  YL14/31,  Section  H,  Level  16,  YL17/5,  Section  H,  Level  19,  sp. A 2 Largest i n d i v i d u a l : left valve, Specimen Y L 2 3 / 5 2 , Section H , Level 25, Harbledownense Zone. 11 Zone.  Figure 3  Left valve, Specimen Y L 3 1 / 1 0 , Section H , Level 33, R e c o g n i t u m  Pteriacea gen. et sp. indet. 1 Specimen Y L 1 4 / 1 8 , Section H , Level 16, Harbledownense Zone.  Figure 4 , 7  Figure 6  Pteriacea gen. et sp. indet. 2 4  Specimen 6 0 9 H / 1 3 , Section D , Level 17, Canadensis Zone.  7  Specimen 6 0 9 D / 1 5 , Section D , Level 21, Canadensis Zone.  Pseudomytiloides  sp.  Specimen Y L 1 4 / 1 6 , Section H , Level 16, Harbledownense Zone.  Figure 8  Limea  ? sp. Specimen 6 1 0 F / 5 , Section D , L e v e l 5, Canadensis Zone.  Figure 9  Oxytoma  sp.  Specimen 7 0 6 H / 6 , Section T , Level 25, A r n o u l d i Zone.  Figure 10  Ichthyosaur vertebral centrum Specimen Y L 3 8 / 1 , Section H , Level 40, R e c o g n i t u m Zone.  Figure 12  Isocrinida gen. et sp. indet. C a l i x w i t h part of c o l u m n , Specimen 6 2 4 A / 1 , Section D , 1 m above Level 26, Canadensis Zone.  

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