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Fossil plants applied to dating of the Hazelton group Whiton, Geoffrey Arthur 1962

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FOSSIL PLANTS APPLIED TO DATING OF THE HAZELTON GROUP by GEOFFREY ARTHUR WHITON B.A. University of B r i t i s h Columbia A Thesis submitted i n p a r t i a l f u l f i l m e n t of the requirements for the degree of MASTER OF SCIENCE _ i n the Department of GEOLOGY We accept this thesis as conforming to the required standards THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1962 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis f o r scholarly purposes may be granted by the Head of my Department or by his representatives. It i s understood that copying or publication of th i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of The University of B r i t i s h Columbia, Vancouver 8, Canada. Date <^ujj A B S T R A C T P o s s i l plant remains from the "upper sedimentary-u n i t " of the Hazeltori Group were investigated i n order to attempt the assignment of a precise age to the s t r a t a . Collections of leaves and specimens for plant m i c r o f o s s i l analysis were coll e c t e d i n the Hazelton area, and were supplemented by l e a f c o l l e c t i o n s loaned by the Geological Survey of Canada. Intensive maceration of rock specimens f a i l e d to y i e l d s u f f i c i e n t m i crofossils for dating or co r r e l a t i o n , and subsequent work was l i m i t e d to the analysis of megafossils. I d e n t i f i c a t i o n of leaves and other remains resulted i n the discovery of one new species and the recog-n i t i o n of 7 species previously unreported i n the Hazelton f l o r a . S t a t i s t i c a l analyses and correlations with other f l o r a s have led to the conclusion that, the f l o r a from the "upper sedimentary u n i t " of the Hazelton Group i s la t e Jurassic to early Cretaceous i n age, encompassing the stages Portlandian to Neocomian i n c l u s i v e . ACKNOWLEDGMENTS Appreciation and thanks are due Dr. G.E. Rouse who suggested this problem and accompanied the writer during the f i e l d c o l l e c t i o n s . The writer i s indebted to Dr. Rouse for his enthusiastic encouragement, technical assistance, constructive c r i t i c i s m s , and thought provoking discussion throughout the course of the work. Thanks are extended to Dr. J.E. Armstrong of the Geological Survey of Canada for information on f o s s i l l o c a l i t i e s i n the Hazelton and Smithers areas. The assistance granted to this problem and the writer in the form of a grant from the Geological Survey of Canada i s g r a t e f u l l y acknowledged. Appreciation i s also due the Geological Survey of Canada for loaning the writer c o l l e c t i o n s of f o s s i l plants from the Hazelton-Smithers area. TABLE OF CONTENTS Page INTRODUCTION 1 Purpose 1 P r e v i o u s Work • . . 1 Geology 2 PART I - METHODS 3 M i c r o f o s s i l s 3 F i e l d C o l l e c t i o n s 3 Laboratory Work 4 M a c r o f o s s i l s 6 F i e l d C o l l e c t i o n s 8 Laboratory Work 8 I d e n t i f i c a t i o n s 9 PART I I - COMPARISON OF THE HAZELTON FLORA WITH OTHER FLORAS IN NORTH AMERICA 21 Comparison w i t h the J u r a s s i c F l o r a o f Cape L i s b u r n e , A l a s k a 25 Comparison w i t h the F l o r a o f the Kennecott Formation, C h i t i n a V a l l e y , A l a s k a . . 26 Comparison w i t h the F l o r a o f the R i d d l e Formation, Douglas County, Oregon 27 Comparison w i t h the F l o r a of the Potomac Group 30 Comparison w i t h the F l o r a o f the Kootenay Formation 32 Comparison w i t h the F l o r a o f the Bl a i r m o r e Formation 33 Lower F l o r a 33 Upper F l o r a 34 PART I I I - INTERPRETATION OF RESULTS 35 CONCLUSIONS 44 BIBLIOGRAPHY' 53 LIST OF PLATES AND FIGURES To follow page Figure 1 9 Figure 2 9 Figure 3 2 2 Figure 4 24 Figure 5 i n folder Plate I 5 1 Plate II 5 2 INTRODUCTION Purpose; The purpose of this thesis i s to attempt an assign-ment of geological age to the "upper sedimentary u n i t " of the Hazelton Group on the basis of f o s s i l plants. Discussion i s l i m i t e d to f o s s i l plants which were coll e c t e d i n the Hazelton and, to a lesser extent, the Smithers map-areas of central B r i t i s h Columbia. Previous Work: The only previous work on dating of the "upper sedimentary u n i t " by f o s s i l plants was done by W.A. B e l l of the Geological Survey of Canada (1956). Prom c o l l e c t i o n s made in the Hazelton area B e l l assigned an early Cretaceous Neo-comian-Barremian age to f l o r u l e s from 13 l o c a l i t i e s and a probable Aptian age to f l o r u l e s from 6 l o c a l i t i e s . An Aptian age was also assigned by B e l l to f l o r u l e s from 7 l o c a l -i t i e s i n the Smithers area. Both Armstrong (1944, 1953) and B e l l (1956) have i n d i -cated that there i s a discrepancy i n the ages indicated by invertebrate evidence on the one hand and by f o s s i l plants on the other. This discrepancy has arisen from the discovery of upper Jurassic or e a r l i e s t Cretaceous marine s h e l l s 300 feet s t r a t i g r a p h i c a l l y above beds containing a f l o r a of Blairmore 2 (Aptian) age. In addition the Hazelton f l o r a was assigned to the Cretaceous by correl a t i o n to the Kootenay, lower Blairmore and Bullhead f l o r a s of Alberta and eastern B r i t i s h Columbia ( B e l l , 1956, p.23), the ages of which are s t i l l i n dispute (Rouse, 1959; Gussow, I960; Pocock, I960). These c o n f l i c t i o n s have led to a general uncertainty as to the age of the "upper sedimentary u n i t " of the Hazelton Group. The present study was undertaken to attempt to shed new evidence concerning the age, p a r t i c u l a r l y by the investigation of plant m i c r o f o s s i l assem-blages. For t h i s purpose the writer, accompanied by Dr. G.E. Rouse, spent 8 days i n mid-September of I960 c o l l e c t i n g f o s s i l plants and samples to be macerated for plant microfossils i n the Hazelton-Smithers area of central B r i t i s h Columbia. These c o l l e c t i o n s , together with most of B e l l ' s o r i g i n a l c o l l e c t i o n s loaned by the Geological Survey of Canada, form the basis for most of the work done i n the present study. Geology; The Hazelton Group, as presently defined, i s known most completely from mapping conducted i n the Hazelton, Smithers, and Terrace map-areas. In the Smithers map-area (Armstrong, 1944) the group consists of the following f i v e map u n i t s : (1) volcanic d i v i s i o n (Lower J u r a s s i c ) . (2) marine sedimentary d i v i s i o n (Middle J u r a s s i c ) . 3 (3) volcanic d i v i s i o n (Middle or Upper J u r a s s i c ) , (4) continental and marine sedimentary d i v i s i o n (Upper Jurassic and Lower Cretaceous). This i s referred to i n subsequent pages as the "upper sedimentary un i t . " (5) volcanic d i v i s i o n (Lower Cretaceous or l a t e r ) . According to Armstrong, the Hazelton Group i n t h i s area has a possible thickness of 10,000 feet. In the Hazelton map-area the two lower members of the Hazelton Group ( l ) and (2), are either missing or have not been recognized (Armstrong, 1953). The lowermost member of the Hazelton Group i n th i s area i s the volcanic d i v i s i o n of Middle Jurassic age (3)« Overlying these volcanics i s the "Upper Jurassic and Lower Cretaceous sedimentary d i v i s i o n " (4) which consists of at least 5000 feet of interbedded continental and marine s t r a t a . Overlying the sedimentary d i v i s i o n i s a volcanic d i v i s i o n of Lower Cretaceous age or younger, corres-ponding to d i v i s i o n 5 of the Smithers map-area. A compre-hensive discussion of the Hazelton Group from other areas has been given by Tipper (1959). PART I - METHODS ( l ) M i c r o f o s s i l s Samples to be macerated for plant m i c r o f o s s i l s were collected from 31 l o c a l i t i e s i n the Hazelton-Smithers area. 4 A l l samples were taken from carbonaceous shales, shaly coals or coaly shales. Many of the shales contained leaf impressions. Care was taken during the sampling to ensure that only fresh material was collected, and that no highly weathered surface material was included i n the samples. Laboratory analyses were performed on the samples for m i c r o f o s s i l s using modifications of the procedure outlined by Rouse (1959). Generally, the basic procedure for the t r e a t -ment of samples i s as follows: (1) The sample i s broken to 1 mm. fragments; (2) The rock fragments are immersed i n hydrochloric acid (HCl) u n t i l a l l v i s i b l e effervescence ceases; (3) The residue i s washed two or three times; (4) Concentrated hydrofluoric acid (HF) i s applied for 12 hours with 3 s t i r r i n g s ; ( 5 ) The residue i s washed three times; (6) Portions of the sample are spot checked under the microscope for indications of plant m i c r o f o s s i l s ; (7) The sample i s immersed i n Schultze's solution ( n i t r i c a cid plus potassium chlorate), or n i t r i c acid alone, depending on the degree of preservation of the m i c r o f o s s i l s . The sample i s p e r i o d i c a l l y checked under the microscope during t h i s step; (8) The oxidized residue i s washed two or three times; (9) A 10% solution of potassium carbonate (K^CO^) i s added for 1 - 1 2 hours. This residue i s checked frequently under the microscope during t h i s step; 5 (10) The residue i s centrifuged and mounted i n corn syrup or a p l a s t i c medium. Treatment of the f i r s t few samples yielded no micro-f o s s i l s , and i t was decided to modify the procedure for sub-sequent samples. The modifications i n the treatment involved the following: (1) The time i n hydrofluoric and hydrochloric acidwas increased (up to 75 hours). In some instances, the acid s o l -utions were replaced with fresh acid, and the number of s t i r r i n g s increased. (2) The time i n Schultze's solution was increased, i n one case up to 141 hours. Increases i n the amount of potassium chlorate i n the Schultze's solution were made. In several i n -stances, where oxidation of carbonized p a r t i c l e s was slow or i n -complete, fresh Schultae's was added to the sample. (3) The time i n 10$ potassium carbonate solution was decreased because some of the fragments appeared to dissolve in the strong solution. (4) Prior to centrifuging (step 10), separation tech-niques involving the " v i b r a f l u t e " and zinc chloride solution (sp. gr. 2.0) were employed. The f i r s t modification of adding fresh HF was intended to dissolve as much rock material as possible from around the plant m i c r o f o s s i l s . The second modification was considered necessary because of the black carbonaceous f i l m remaining on the "m i c r o f o s s i l s " following normal treatment. 6 I t was hoped that by i n c r e a s i n g the time i n S c h u l t z e ' s s o l u t i o n , the c o a l y f i l m would be removed. The f i r s t two m o d i f i c a t i o n s were o n l y p a r t i a l l y s u c c e s s f u l . The t h i r d m o d i f i c a t i o n was made i n order to discount any p o s s i b i l i t y o f m i c r o f o s s i l s having been completely d i s s o l v e d by ex c e s s i v e immersion i n the potassium carbonate s o l u t i o n . T h i s m o d i f i c a t i o n gave ne g a t i v e r e s u l t s . The f o u r t h m o d i f i c a t i o n i n the treatment procedure was made i n order to dispose o f excess rock m a t e r i a l and hence f a c i l i t a t e a b e t t e r c o n c e n t r a t i o n o f m i c r o f o s s i l s i n the sample. The " v i b r a f l u t e " and z i n c c h l o r i d e treatments were s u c c e s s f u l i n d i s -posing o f excess f i n e rock m a t e r i a l i n some samples, but d i d not i n c r e a s e the y i e l d o f m i c r o f o s s i l s . • Treatment o f a l l 31 samples y i e l d e d o n l y a very few po o r l y preserved p l a n t m i c r o f o s s i l s . In order to ensure that the treatment procedures were e f f e c t i v e , 3 of the more "promis-i n g " samples were r e t r e a t e d . Two samples were r e t r e a t e d once, and the other sample was r e t r e a t e d t w i c e , w i t h negative r e s u l t s . At t h i s stage, work on the m i c r o f o s s i l samples was d i s -c ontinued. I t i s considered that a l t h o u g h the w r i t e r ' s work gave n e g a t i v e r e s u l t s , f u r t h e r sampling i n the Hazelton area f o l l o w e d by exhaustive s t u d i e s i n the l a b o r a t o r y would probably y i e l d a l i m i t e d m i c r o f l o r a . (2) M a c r q f q s s i l s P l a n t m a c r o f o s s i l s were c o l l e c t e d from 16 l o c a l i t i e s i n the Hazelton-Smithers a r e a (see sample l o c a l i t y map, f i g . 5 ) . 7 Of this number, 14 are i n the Hazelton map area and two are i n the Smithers map area. Altogether, over 300 specimens were col l e c t e d . Most of these are compressions of leaves although a few stem fragments were included. In addition to the previously mentioned macrofossils, c o l l e c t i o n s of the Geological Survey of Canada from an addit-ional 14 l o c a l i t i e s i n the Hazelton area were made available to the writer. Some of these c o l l e c t i o n s were made prior to publication of W.A. B e l l ' s memoir i n 1956; others were made since that time by personnel of the Geological Survey, and serve to increase the areal d i s t r i b u t i o n of Hazelton species. TABLE I Geological Survey of Canada F o s s i l Plant L o c a l i t i e s (These are the l o c a l i t i e s as given by the Geological Survey of Canada) Locality__Nq. 2386 HaBelton area, from ridge L at elevation 6220 feet, 2388 Hazelton area, from head of Salmon River. 2393 Hazelton area, Canyon Creek, Skeena River Valley. 2394 Hazelton area, Canyon Creek, Skeena River Valley. 2408 Suskwa River, 1/2 mile above 20 mile Creek. 2413 Creek flowing into Skeena River opposite Hazelton. 2419 2 miles up Campbell Creek from Kispiox River. 4993 2 miles along short distance road leading to S i l v e r Standard Mine, east of Hazelton. 4996 Old road cut, of Hazelton. approach to Skeena River bridge north 8 4 9 9 8 Road cut on # 1 6 just east of bridge over Kitsequela, east of Skeena Crossing. 4 9 9 9 Road cut on road north of Kispiox ( 1 5 . 2 miles from where road leaves # 1 6 ) . 5 0 0 0 West end of 1 7 mile bridge on Kispiox River (= l o c . H-26). 5 0 5 4 Rocher de Boule Range. , 5 0 5 5 Rocher de Boule Range. The most noteworthy feature of the f i e l d c o l l e c t i o n s i s the apparent segregation of the plant species i n s t r a t a from di f f e r e n t l o c a l i t i e s . For example, of 2 9 l o c a l i t i e s 7 contain only one species, 6 contain 2 species, 3 contain 3 species, 2 contain 4 species, 2 contain 5 species, 4 contain 6 species, 5 contain 7 species and 1 l o c a l i t y contains 1 0 species. In 16 of 29 l o c a l i t i e s ( 5 5 . 1 $ ) 3 species or less are present. It i s observed also ( f i g . 1) that i n the case of l o c a l i t i e s con-taining several'species, generally 1 and sometimes 2 species comprise the bulk of the f l o r u l e at these l o c a l i t i e s . The d i s t r i b u t i o n of species among the 2 9 l o c a l i t i e s can be shown also by the following data which are derived from f i g . 1: 11 species occur i n 1 l o c a l i t y . 1 0 species occur i n 2 l o c a l i t i e s . 4 species occur i n 3 l o c a l i t i e s . 3 species occur i n 4 l o c a l i t i e s . 4 species occur i n 5 l o c a l i t i e s . 1 specie occurs i n 6 l o c a l i t i e s . 1 specie occurs i n 8 l o c a l i t i e s . 1 specie occurs i n 1 2 l o c a l i t i e s . 1 specie occurs i n 1 5 l o c a l i t i e s . 9 From the above table It i s observed that 32 of 36 species (88.8$) i d e n t i f i e d occur i n 5 l o c a l i t i e s or l e s s , and that 11 of 36 species (30.5$) occur i n 1 l o c a l i t y . The d i s t r i b u t i o n of the species according to l o c a l i t i e s i s shown i n figure 1, and the frequency of species d i s t r i b u t i o n i s shown i n f i g . 2. It i s apparent that there are no s i g n i f i -cant discrepancies i n the d i s t r i b u t i o n which would suggest that there are plants of differ e n t ages represented. This i s further substantiated by the r e l a t i v e l y close geographic proximity of many of the c o l l e c t i n g s i t e s , and the general l i t h o l o g i c s i m i l a r i t i e s of the rocks containing the plants. Thus i t appears most reasonable to consider the plants from a l l of the l o c a l -i t i e s collected i n the "upper sedimentary unit" of the Hazelton Group as belonging to a single contemporaneous and syngenetic f l o r a . This i s i n marked contrast to the suggestions of B e l l ( i n Armstrong, 194-4; B e l l , 1956, p.23) that some f l o r u l e s are of probable Aptian age, others of Cretaceous age (Neocomian-Barremian), while s t i l l others were admitted as possibly Jurassic age. Id ent i f i c a t ions A l l specimens collected by the writer were numbered (B-3084 to B-3432) and are housed i n the permanent c o l l e c t i o n of the Department of Biology and Botany at the University of B r i t i s h Columbia. No type specimens were available and a l l i d e n t i f i c a t i o n s were made by comparison o f the specimens on hand w i t h p h o t o -g r a p h s , i l l u s t r a t i o n s , and w r i t t e n d e s c r i p t i o n s o f p r e v i o u s l y d e s c r i b e d forms. E x a m i n a t i o n o f the specimens i n v o l v e d use o f a 10 power hand l e n s and, t o a l e s s e r e x t e n t , a b i n o c u l a r m i c r o -scope. I n g e n e r a l , the b i n o c u l a r m i c r o s c o p e was not s a t i s -f a c t o r y f o r t h i s t y p e o f work because h i g h m a g n i f i c a t i o n en-l a r g e d t h e m i n e r a l g r a i n s i n the r o c k t o such an e x t e n t t h a t d e t a i l s o f the p l a n t s were ob s c u r e d r a t h e r t h a n improved. From the two c o l l e c t i o n s s t u d i e d ( i . e . , t he w r i t e r ' s c o l l e c t i o n and t h a t o f t h e G e o l o g i c a l Survey o f Canada), a t o t a l o f 560 specimens r e p r e s e n t i n g 36 s p e c i e s , were i d e n t i f i e d . S e venteen o f the 36 s p e c i e s were i d e n t i f i e d as p r e v i o u s l y d e s c r i b e d s p e c i e s , some were compared to s p e c i e s , and s t i l l o t h e r s were i d e n t i f i e d o n l y to genus. The summary l i s t o f s p e c i e s t h a t f o l l o w s i s a com-p i l a t i o n from 3 s o u r c e s : (1) A l l s p e c i e s i d e n t i f i e d from the w r i t e r ' s c o l l e c t i o n (2) S p e c i e s i d e n t i f i e d from the G e o l o g i c a l Survey o f Canada c o l l e c t i o n s t h a t were made a v a i l a b l e t o t h e w r i t e r ; (3) S p e c i e s i d e n t i f i e d by W.A. B e l l (1956) but w h i c h a r e not r e p o r t e d i n e i t h e r (1) or (2) above. I n t h i s summary l i s t t he s o u r c e c o l l e c t i o n f o r each p l a n t s p e c i e s i s d e s i g n a t e d as f o l l o w s : W f o r s p e c i e s from the w r i t e r ' s c o l l e c t i o n , G.S.C. f o r s p e c i e s from the G e o l o g i c a l Survey c o l l e c t i o n s a v a i l a b l e to the w r i t e r , and B f o r s p e c i e s not found i n e i t h e r o f the f o r e g o i n g but r e p o r t e d by W.A.Bell 11 In h i s memoir. Forms marked w i t h an a s t e r i s k have not been p r e v i o u s l y r e p o r t e d i n the Hazelton f l o r a . Source o f C o l l e c t i o n D i v i s i o n ARTHROPHTTA Order EQUISETALES W E q u i s e t i t e s l y e l l i ( M a n t e l l ) Unger W E q u i s e t i t e s sp. c f . l y e l l i ( M a n t e l l ) Unger D i v i s i o n PTEROPHYTA Order FILICALES w C l a d o p h l e b l s sp. W ? C l a d o p h l e b l s sp. G.S.C. & C l a d o p h l e b i s h e t e r o p h y l l a Fontaine W C l a d o p h l e b i a impressa B e l l B C l a d o p h l e b i s parva Fontaine W ft ? C l a d o p h l e b i s ( G l e i c h e n i t e s ) p o r s i l d i Sewarfl w C l a d o p h l e b i s v i r g i n i e n s i s Fontaine emend B e r r y W C l a d o p h l e b i s sp. c f . v i r g i n i e n s i s F o n t a i n e emend Ber r y W C o n i o p t e r i s sp. W C o n i o p t e r i s b r e v i f o l i a (Fontaine) B e l l G.S.C. i i C o n i o p t e r i s (Sphenopteris) hymenophylloldes (Brdrigniart) Seward B D i c t y o p h y l l u m f u c h s i f o r m e ( B e l l ) Seward W G l e i c h e n i t e s sp. 12 ¥ B B B G.S.C. B Di v i s i o n PTERIDOSPERMOPHYTA Order CAYTONIALES G.S.C. Sagenopteris sp. B Sagenopteris W i l l i a m s i (Newberry) B e l l D i v i s i o n CYCADOPRYTA Orders BENNETTITALES and CYCADALES B Ctenopteris i n s i g n i s Fontaine B Ni l s s o n i a brongniarti (Mantell) Dunker w N i l s so n i a canadensis B e l l W N i l s s o n i a parvula (Heer) Fontaine W _ N i l s s o n i a pterophylloides Nathorst B N i l s s o n i a s chaumburgens i s (Dunker) Nathorst B Pseudoctenis hazeltonensis B e l l B Pseudocycas dunkeriana (Goppert) F l o r i n W i Pterophyllum tennuipinnatus n. sp. B Pterophyllum rectangulare B e l l G.S.C. A Ptilophyllum arcticum (Goppert) Seward Gleichenites nordenskioldi (Heer) emend Seward Klukia canadensis B e l l Phlebopteris ? elongata B e l l Sphenopteris acrodentata Fontaine S phenopt eris dentata (Velonovsky) Seward Sphenopteris (Ruf fordia) gqpperti (Dunker) Seward 13 B B B Di v i s i o n GINKGOPHYTA Order GINKGOALES W Baiera sp. cf. furcata (Lindley and Hutton) Braun G.S.C. Baiera sp. cf. gracilus (Bean) Bunberry W Ginkgoites arcticus- (Heer) F l o r i n W Ginkgoites sp. cf. arcticus (Heer) F l o r i n W Ginkgoites s i b i r i c a Heer W Ginkgo sp. cf. s i b i r i c a Heer Di v i s i o n CONIFEROPHYTA Order CONIFERALES B Athrotaxites berry! B e l l ¥ ? Elatides sp. V/ Elatides c u r v i f o l i a (Dunker) Nathorst B Elatides splendida B e l l W _ ? Elatocladus, sp. W Pityophyllum sp. B Pityophyllum cf. nordenskiol'dl (Heer) Krystofovich INCERTAE SEDIS ¥ Czekanowskia sp. ¥ Czekanowskia sp. cf. r i g i d a Heer Ptilophyllum Columbianurn B e l l Ptilophyllum hirturn B e l l Ptilophyllum (Anomozamites) montanense CFontaine) B e l l 14 B P h o e n i c o p s i s a r c t i c a (Heer) W ? Podozamites sp. W Podozamites sp. W Podozamites l a n e e o l a t u s ( L i n d l e y and HuttonT~ Schimper The d i s c u s s i o n i n the f o l l o w i n g pages i s l i m i t e d t o th o s e p l a n t s about w h i c h the w r i t e r has new i n f o r m a t i o n , o r w h i c h have not been t r e a t e d a d e q u a t e l y i n former i n v e s t i g a t i o n s . The photographs ( p l a t e s 1 and 2 ) a r e p r e s e n t e d t o supplement the d i s c u s s i o n o f s p e c i e s i n the t e x t , and to i l l u -s t r a t e the s i g n i f i c a n t f e a t u r e s o f s p e c i e s r e p o r t e d here f o r the f i r s t t i m e . G e n e r a l l y , two problems were encountered i n the i d e n -t i f i c a t i o n o f the p l a n t s . The f i r s t problem was t h a t o f h a v i n g to d e a l w i t h many i m p e r f e c t l y p r e s e r v e d specimens. The second and most f r u s t r a t i n g problem, was the v a r i a t i o n shown i n photo-graphs and d e s c r i p t i o n s o f some p r e v i o u s l y r e p o r t e d s p e c i e s . These v a r i a t i o n s a l l o w e d f o r c o n s i d e r a b l e o v e r l a p p i n g o f s p e c i e s i n some c a s e s , and most c e r t a i n l y p o i n t out the need f o r r e v v i s i o n o f some o f the p l a n t groups encountered i n t h i s s t u d y . The l a t t e r problem, t h a t o f v a r i a t i o n among s p e c i e s , i s exem-p l i f i e d s t r o n g l y by C l a d o p h l e b i s v i r g i n i e n s i s and C o n i o p t e r i s b r e v i f o l i a . I n c o n s i d e r i n g the problem o f -plant s p e c i a t i o n , and i n p a r t i c u l a r l e a v e s from one p l a n t (eg. G i n k g o ) , u n l e s s measurable v a r i a t i o n s e x i s t , s p e c i e s cannot be s e p a r a t e d ade-q u a t e l y . 15 E q u i s e t i t e s : Although the specimens of Equisetites l y e H i (Mantell) Unger (plate 1 , f i g . 12) are incomplete, the excellent preservation allows for i d e n t i f i c a t i o n to be made with consider-able confidence. This species is r e l a t i v e l y rare i n the Hazelton f l o r a . Cladophlebis t In the many specimens of Cladophlebis v i r g i n i e n s i s Fontaine which were studied by the writer, i t i s considered v i r t u a l l y impossible to esta b l i s h any d i s t i n c t boundaries be-t\\reen the many variants, as they grade imperceptibly into each other. B e l l ( 1 9 5 6 , p. 51-52) recognized three main variants of Cladophlebis v i r g i n i e n s i s . However, the present writer was un-able to do this because of the fact that imperfect preservation of the specimens made i t impossible to observe d e t a i l s of venation. It i s considered that among the specimens of Cladophlebis v i r g i n i e n s i s studied by the writer there are forms which could be referred just as eas i l y to Cladophlebis denticulata, since some forms of this l a t t e r species with entire margins do not d i f f e r i n any eas i l y observable or measurable character from forms of Cladophlebis y i r g i n i e n s i s i n the Hazelton f l o r a . The writer has had available for study a specimen of Cladophlebis  denticulata from the Jurassic of Yorkshire, England, i n which imperfect preservation does not allow venation d e t a i l s to be noted. However, the general shape of the pinnules, t h e i r angle and manner of attachment to the rachis, and their apparently 16 entire margins suggest strongly that the specimen i s t y p i c a l of some forms of Cladophlebis v i r g i n i e n s i s i n the Hazelton f l o r a . Coniopteris: Coniopteris b r e v i f o l i a (plate 2, f i g . 14) i s the most common leaf in the Hazelton f l o r a next to Cladophlebis  v i r g i n i e n s i s . Once again, because of the great v a r i a b i l i t y of th i s species, i t overlaps certain forms referred by other authors, notably by Seward (1900, p. 99) to Coniopteris  hymenophy1loides. The writer has i d e n t i f i e d several specimens °£ Coniopteris hymeno phy l l o id es, which are i d e n t i c a l in. mor-phology to the English Jurassic species (see plate 1, f i g . lOw). At the same time, however, some of the l e a f remains are i d e n t i c a l with Coniopteris b r e v i f o l i a from the Potomac f l o r a . However, there do not appear to be any s a t i s f a c t o r y c r i t e r i a for d i s t -inguishing between the many variants of the two species, and there i s a good p o s s i b i l i t y that the 2 f o s s i l species represent one natural species. Sphenopteris: Leaves named Sphenopteris l a t i l o b a Fontaine ( i n B e l l , 1956, p. 69-70) had been synonymized previously by Seward i n 1926 under Sphenopteris dentata Velonovsky (Plate 1, f i g . 5)j and hence should bear the l a t t e r name. Nil s s o n i a : N i l s s o n i a parvula, an abundant form at l o c a l i t y H-8, i s considered by the writer to be synonymous with N i l s s o n i a  n i g r a c o l l e n s i s Wieland, (in Ward, 1905, p. 320) and B e l l (1956, p.103). B e l l i n reference to Nilssonia n i g r a c o l l e n s is writes: 1 7 "Nilssonia parvula, Fontaine (non Heer)... obviously belongs to t h i s species." Fontaine ( i n Ward, 1 9 0 5 } p. 3 2 0 ) writes as follows: "This plant (N. n i g r a c o l l e n s i s ) i s s t r i k i n g l y l i k e N i l s s o n i a parvula (Heer) Fontaine of the Jurassic of Oregon. As however i t i s constantly larger, and more robust than the predominant forms of that f o s s i l , i t i s probably d i s t i n c t . " N i l s s o n i a parvula was f i r s t described as Taeniopteris parvula by Heer i n I876 , and since i t i s obviously con-specific with and takes precedence over N. n i g r a c o l l e n s i s , the writer has seen f i t to r e i n s t i t u t e this species. Pterophyllum (Ctenophyllum): In the writer's c o l l e c t i o n of Hazelton plants are 5 specimens which are s t r i k i n g l y similar to forms from the Oregon Jurassic f l o r a which Fontaine ( i n Ward, 1 9 0 5 , p. 1 0 5 , p i . XXII) has referred to Ctenophyllum angustifolium. Ctenophyllum, however, as o r i g i n a l l y defined by Schimper (Fon-taine, 1 8 8 3 j p. 67) has the pinnae attached to the upper surface on the rachis and, according to Seward, (19175 p. 5 2 8 ) d i f f e r s in no s i g n i f i c a n t respects from forms of Ptilophyllum or fronds o f Dioonites. Consequently, as Seward (1917} p. 5 2 8 ) has pointed out, there would seem to be no adequate reason for the retention °f Ctenophyllum as a generic designation. A transfer preparation of one of the writer's specimens shows that the pinnae are attached l a t e r a l l y as i n species of the bennettitalean genus Pterophyllum. Consequently, i t was planned, o r i g i n a l l y to e s t a b l i s h a new combination for this plant under Pterophyllum angustifolium. However, since this 18 name has already been used for another species of Pterophyllum (Seward, 1900, p. 228), the only alternative i s the circum-s c r i p t i o n of a new species of Pterophyllum. This i s given below. Seward (1917, p. 549), i n reference to Pterophyllum  n a t h o r s t i , writes: "The Jurassic fronds from Oregon described by Fontaine as Ctenophyllum angustifoliurn are similar forms." Although these two species are indeed somewhat s i m i l a r , the differences between them are s u f f i c i e n t to preclude any attempt to combine the forms referred to C t enqp hy Hum angustifolium under Pterophyllum nathorsti. Probably the most s t r i k i n g difference between these two species i s that Pterophyllum nathorsti has up to 16 veins per pinnule, whereas the Oregon and Hazelton forms are characterized by 3 to 5 veins per pinnule. The Hazelton specimens have a constant number of veins (4). Pterophyllum t ennuip innatus n. sp. 1896 - Ctenophyllum angustifolium Fontaine: Am. Journ. S c i . 4th ser., Vol. I I , p. 274 (nomen). 1900 - Ctenophyllum angustifolium Fontaine: Twentieth Ann. Rep. U.S. Geol. Surv., 1898-99, Pt. I I , p. 360, p i . LXIII, f i g s . 2, 3. 1905 - Ctenophyllum angustifolium Fontaine: U.S. Geol. Surv., Mon. 48, p. 105, p l . XXII. 1916 - Ctenophyllum angustifqlium ? Fontaine: U.S. Nat. Mus., P r o c , v o l . 51, p. 4-58, p l . 80, f.2. Type Specimen B-3407, and counterpart B-3399, University of B r i t i s h Columbia Paleobotanical C o l l e c t i o n . Description: Frond: fragments 8 cm. long are av a i l a b l e , but the o r i g i n a l length must have approached 15 cm. o b l o n g - e l l i p t i c a l in outline, narrowing toward base and apex. fragments 7 cm. wide. Leafle t s : - i n the basal regions, l e a f l e t s are perpendicular to the axis; i n the d i s t a l region becoming more and more i n c l i n e d , or somewhat f a l c a t e (more so i n the d i s t a l parts of l e a f l e t s ) . l e a f l e t s are generally s l i g h t l y expanded at base and some appear to coalesce with adjacent pinnules;' others have width unchanged to middle of pinnule and then narrow gradually to the t i p . width of l e a f l e t s varies from 2 to 3 mm., and de-creases towards leaf apex. the tip s of l e a f l e t s are obtusely rounded. the longest l e a f l e t observed i s 6 cm. long-. the spacing between" adjacent l e a f l e t s varies from 15 to 1 .5 mm. Attachment ; to r a c h i s ; - alternate to opposite, but mostly sub-opposite. the l e a f l e t s are attached l a t e r a l l y on the rachis. This was suspected i n the hand specimen and con-firmed by the transfer preparation. Rachis:- whole width of rachis i s exposed and uncovered by l e a f l e t bases. rachis varies from 2 to 3 . 5 mm. i n width, decreases towards apex of frond generally. Venation:- the veins are non-branching, are 3 to 5 i n number and are p a r a l l e l a l l the way out to the d i s t a l ends of the l e a f l e t s . 20 Baierat The problem of species v a r i a t i o n together with that of imperfect preservation did not permit s p e c i f i c i d e n t i f i c a t i o n of specimens of Baiera. None of the.specimens showed enough of the le a f lamina or s u f f i c i e n t venation to be certain of a species a f f i n i t y . Consequently, these specimens could be i d e n t i f i e d with confidence only as "sp. c f . g r a c i l u s " (plate 2, f i g . 16) or "sp. cf. furcata" (plate 2, f i g . 15). Similar reservations were noted by B e l l (1956). Ginkgo: Two species of Ginkgo were distinguished by the writer as Ginkgoites s i b i r i c a (plate 2, f i g . 6) and Ginkgoites arcticus (plate 2, f i g . 3). F l o r i n (1936, p. 34). Some specimens were r e l a t i v e l y easy to i d e n t i f y , whereas others were most d i f f i c u l t to assign to one species or the other. It should be mentioned here that Ginkgoites arcticus has been ca l l e d Ginkgo p l u r i p a r t i t a by B e l l (1956, p. 85) and other authors, but represents a previously omitted synonymy. In r e f e r r i n g several 'Ginkgos" to Ginkgoites s i b i r i c a , I have been influenced by A.C.Seward (1919, p. 24) who wrote: "For the present the most convenient course would seem to be the retention of Ginkgoites s i b i r i c a for leaves' similar to some of the more deeply divided forms of G. d i g i t a t a and to G. p l u r i p a r t i t a , but normally character-ized by a lamina divided almost or quite to the base into oblong, obtuse or more or less acute segments." t The writer considers Ginkgo nana Dawson ( i n B e l l , 1956, p. 86) synonymous with the e a r l i e r Ginkgoites s i b i r i c a . B e l l (1956, p. 86) states i n reference to Ginkgo nana and two sim i l a r species that: "In form and venation a l l three of these species are much l i k e Ginkgoites s i b i r i c a , (Heer) Seward, ... Although they are of smaller size than normal with that species." 21 B e l l (1956, p. 86) gives i n his l i s t of synonymies for Ginkgo nana the species S a l i s b u r i a (Ginkgo) s i b i r i c a Dawson, 1886. However, Ginkgoites s i b i r i c a (Heer, 1876) Seward, by rules of botanical nomenclature, takes p r i o r i t y over Dawson's species. On the problem of i d e n t i f i c a t i o n of Ginkgo leaves i n general, Seward (1919, p. 14) writes: " I t i s impossible to define precisely the several species of Ginkgoites founded on leaves; i n the account of the recent species attention i s c a l l e d to the range i n leaf form and i t s bearing on the deter-mination of f o s s i l s . A l l that can be done i s to adopt certain s p e c i f i c names as a matter of conven-ience, recognizing that the differences on which the c l a s s i f i c a t i o n i s based are not either s u f f i c i e n t l y sharply defined or morphologically important to be regarded as c r i t e r i a of true s p e c i f i c d i s t i n c t i o n . " F.H. Knowlton (1914, p. 55) writes as follows on t h i s topic: > "In dealing with such an abundance of specimens and m u l t i p l i c i t y of forms, one must needs make either many 'species' to accommodate this d i v e r s i t y , or only one or two, and i n view of the known v a r i a t i o n exhibited by the single l i v i n g species, the l a t t e r plan seems preferable." These l a s t two quotations serve to. i l l u s t r a t e the many variations i n ginkgoalean leaves; these r e s u l t i n im-measurable d i f f i c u l t i e s i n s p e c i f i c i d e n t i f i c a t i o n and indicate that leaves of Ginkgo have l i t t l e use i n c o r r e l a t i o n or dating. PART II - COMPARISON OF THE HAZELTON FLORA WITH OTHER FLORAS IN NORTH AMERICA In attempting to date the Hazelton f l o r a by comparisons and' correlations with other f l o r a s , i t i s apparent that there 22 are very few f l o r a s of comparable age i n North America. With a few exceptions of r e l a t i v e l y small f l o r a s , the only ones con-sidered suitable for c o r r e l a t i o n with the Hazelton f l o r a are those l i s t e d i n the following paragraphs (see also f i g . 3 and f i g . 4). Rather than attempting long distance inter-continental c o r r e l a t i o n s , i t i s considered that, by l i m i t i n g the c o r r e l -ations to r e l a t i v e l y short (intra-continental) distances, the v a l i d i t y of the correlations w i l l be increased. Simpson (i960) discusses several methods for the measure-ment of faunal resemblance under the following two groups; ( l ) measurement iased on numbers of taxa; (2) measures involving abundance of taxa. The application of the l a t t e r measurements cannot be undertaken i n the present study, as numbers of species are only p a r t i a l l y known for the Hazelton f l o r a , and are un-known for other f l o r a s with which the Hazelton f l o r a can be com-pared. According to Simpson, the most obvious and acceptable measurement of faunal resemblance i s expressed as follows: C x 100 /', x N t U > where C = number of taxa common to both faunas; N^ ' = t o t a l taxa i n both. If both faunas are almost completely represented and i f they are of at least approximately equal size, the above index ( l ) i s useful. . Samples, however, are frequently of unequal size and the following index eliminates this disadvantage: C x 100 / 9 v where C = number of taxa common to both faunas; = t o t a l taxa in the smaller of the two faunas compared. As an estimate of a population index from samples, the second index minimizes the eff e c t s of differences i n size between two faunas. When samples are small, both ( l ) and ( 2 ) have considerable sampling error; but ( 2 ) i s also preferable i n this respect, and the larger the discrepancy between N-^  and ( t o t a l taxa i n the larger of the two faunas compared), the better but not i s sampled, the lower the bias r e s u l t i n g from the sampling error. When the sample (and population) sizes are equal, index ( 2 ) i s s t i l l at least as good as ( l ) . The % correlations for the 4 largest f l o r a s (Oregon, Patuxent, Grundel and Patapsco) have been calculated using index ( 2 ) , with the Hazelton f l o r a as N-^ . Three f l o r a s , v i z . , Kootenay, lower Blairmore and upper Blairmore, are of s l i g h t l y smaller size than the Hazelton, and i n these cases N-^  represents the smaller f l o r a . Both the Kennecott and Cape Lisburne f l o r a s are much smaller than the Hazelton and again i s the smaller figure. The resultant measurements are presented i n figure 3 , and are given again under the detailed discussion of each f l o r a . In the following section, a l l correlations have been made on the basis of number of species i d e n t i f i e d s p e c i f i c a l l y plus the number of diff e r e n t species i d e n t i f i e d as "sp. c f . " This l a t t e r group includes species i n brackets. 24 In the section on "Interpretation of Results," c o r r e l a t -ions made on the basis of species only are discussed. These correlations do not include bracketed species, i n the following section, unless such species represent established synonymies. It i s observed i n the summary l i s t (pages 11 to 14) and figure 4, that the Hazelton f l o r a has 35 species i d e n t i f i e d s p e c i f i c a l l y and 4 species i d e n t i f i e d as "sp. c f . " For the other f l o r a s discussed i n subsequent pages, the following table summarizes the number of species i d e n t i f i e d s p e c i f i c a l l y etc., for each f l o r a which i s used as N^ i n index (2). TABLE II Cape Lisburne Kennecott Kootenay Lower Blairmore, Upper Blairmore^ Total Species 17 16 33 37 35 Number of species iden-t i f i e d specif-i c a l l y . 16 8 21 33 18 Number of species i d e n t i f i e d spec-i f i c a l l y plus number i d e n t i f i e d as sp. c f . 17 11 26 36 20 In figure 4, where presence of a species i s another f l o r a i s indicated by quotation marks, that species i s a "c f . " species. The l i s t of species i n figures 1 and 2 i s a compilation from the writer's c o l l e c t i o n of plants, and the Geological Survey of Canada c o l l e c t i o n s loaned to the writer. Some of the species l i s t e d by B e l l (1956) and also given i n the f l o r a l l i s t s i n succeeding pages, are not included i n figures 1 and 2. This i s because the writer has no information on the frequency of occurrence; or on the numbers of individuals of these species. Although a record of the occurrence of species said to be " c h a r a c t e r i s t i c of the Jurassic period" etc., i s useful information for dating a f l o r a , the method i s subject to personal opinion. I f , however, a s t a t i s t i c a l method, as out-l i n e d can be used i n conjunction with the " c h a r a c t e r i s t i c species" method, the r e s u l t s should prove to be much more meaning-f u l and objective. Jurassic F l o r a of Cape Lisburne, Alaska F.H. Knowlton (1914) has i d e n t i f i e d seventeen species of plants from the Cape Lisburne region of northwestern Alaska. 16 of the plants are i d e n t i f i e d s p e c i f i c a l l y . These plants are contained i n the Corwin formation. The f l o r a of the Cape Lisburne region includes the following species which are also present i n the Hazelton f l o r a . Where a Cape Lisburne species d i f f e r s i n name from the Hazelton equivalent, the Hazelton species i s given i n brackets. Coniopteris hymenophylloides. "Podozamites lanceolatus. El a t i d e s c u r v i f o l i a . ' Pityophyllum nordenskioldi. Ginkgo d i g i t a t a (Ginkgoites a r c t i c u s ) . These f i v e species r e s u l t i n a 29.4% c o r r e l a t i o n with the Hazelton f l o r a . The l a s t species named above ( i . e . Ginkgo  d i g i t a t a , i n Knowlton, plate VII, f i g . 5) appears s t r i k i n g l y s i m i l a r to species i n the Hazelton flora, that the writer has referred to Ginkgoites ar c t i c u s , and consequently has been i n -cluded i n a l i s t of species common to both f l o r a s . Flora of the Kennecott Formation (Albian) Chitina Valley, Alaska The f l o r a of the Kennecott formation (Knowlton, i n Martin, 1926, p. 344—346) includes 16 species of which only 8 are i d e n t i f i e d s p e c i f i c a l l y . The following species are also present i n the Hazelton f l o r a . Where a Kennecott species d i f f e r s i n name from the Hazelton equivalent, the Hazelton species i s given i n brackets. Elatides c u r v i f o l i a . Pinus nordenskioldi (Pityophyllum nordenskioldi). Ginkgo schmidtiana (Ginkgoites s i b i r i c a ) . Podozamites sp. (Podozamites lanceolatus). Taeniopteris parvula? (Nil s s o n i a parvula). Cladophlebis c f . C. moissenti (Cladophlebis heterophylla). These 6 species result i n a 54.5$ cor r e l a t i o n with the Hazelton f l o r a . Pinus nordenskioldi has been synonymized with Pityophyllum nordenskioldi ( i n B e l l , 1956, p. 112). I t i s also probable that some of the specimens i n the Hazelton f l o r a , referred by the writer to Pityophyllum sp., are referable to 27 t h i s species although such an assignment cannot be made with confidence. Ginkgo schmidtiana i s referable to Gingoites s i b i r i c a of the Hazelton f l o r a (Seward, 1919, p.24). Knowlton ( i n Martin, 1926, p.34-4) states, "The Podozamites i s of the type P. lanceolatus..," hence i t appears that t h i s form i s also common to the Hazelton f l o r a . In reference to the forms of Cladophlebis present, Knowlton ( i n Martin, 1926, p. 344) writes: "One form may be compared with C. moissenti from the French Jurassic, or with C. heterophylla as known from the Kootenai." Consequently, t h i s form has been included, though possibly somewhat doubtfully, i n the l i s t of species common to both the Kennecott and Hazelton f l o r a s . Flora of the Riddle Formation, Douglas County, Oregon (Portlandian, Middle to Late Tithonian) F.H. Knowlton (1910) l i s t s 79 plant species plus 2 indeterminate leaves from the plant beds of Douglas. County, Oregon. S i x t y - f i v e of the 79 plants are i d e n t i f i e d s p e c i f i c a l l y . The following species are also present i n the Hazelton f l o r a . Where an Oregon species d i f f e r s i n name from the Hazelton equivalent, the Hazelton species i s given i n brackets. Coniopteris hymenophylloides. Thyrsopteris murrayana (Coniopteris hymenophylloides). Polypodium oregonense (Cladophlebis_ parva). Cladophlebis vaccensis (Cladophlebis v i r g i n i e n s i s , pars.). 28 Ruffordia gopperti. N i l s s o n i a parvula. N i l s s o n i a pterophylloides. Pinus nordenskioldi (Pity_qphyllum nordenskio>ld1 i ) . Ctenophyllum angustifolium (Pterophyllum tennuipinnatus). Podozamites laneeolatus. Ginkgo d i g i t a t a (Ginkgoites_ a r c t i c u s ) . Ginkgo s i b i r i c a . Sagenopteris g r a n d i f q l i a (Sagenopt eris W i l l i a m s i ) . PterophylluiTi contiguum (Ptilophyllum arcticum). Pterophyllum aequale (Ptilophyllum columbianum). Cladophlebis denticulata (Cladophlebis v i r g i n i e n s i s , pars.). Taeniopteris o r o v i l l e n s i s (Nilssqnia. canadensis). Ginkgo lepida (Ginkgoites s i b i r i c a ) . The foregoing l i s t r e sults i n a 46.1% co r r e l a t i o n with the Hazelton f l o r a . Thysopteris murrayana has been synomymized under Coniopteris hymenophylloides by Seward (1900, p. 100), however, Fontaine ( i n Ward, 1905, p. 61) maintains they are separate species. W.A.Bell (1956, p.57) i n reference to Polypodium oregonense Fontaine (in Ward, 1905, PI. X, f i g . 1-7) states i n part: 29 Fontaine's species Cladophlebis vaccensis ( i n Ward, 1905 5 p. 6 6 - 6 8 , plate X, f i g . 8-12) appears i d e n t i c a l to forms i n the Hazelton f l o r a which the writer has referred to .Cladophlebis v i r g i n i e n s i s , and for this reason i s included i n the l i s t of plants common to both f l o r a s . Some of the forms referred by Fontaine to Ginkgo  d i g i t a t a (in Ward, 1905, p l . 30, f i g . 1-7) are seemingly i d e n t i c a l to Ginkgoites arcticus in.the writer's c o l l e c t i o n of Hazelton plants: t h i s i s especially true of Fontaine's f i g . 5 which shows the lobes dissected to the same degree as the Hazelton specimens. Other s i m i l a r i t i e s noted i n species of ginkgos are as follows: (1) Ginkgo hutton! magnifolia ( i n Ward, 1905, p l . 31? f i g . 4?r8) i s , i n the opinion of the wr i t e r , i d e n t i c a l with specimens of Ginkgoites arcticus i n the Hazelton f l o r a . (2) Some forms that Fontaine (in Ward, 1905, plate 32, f i g . 3-8) has referred to Ginkgo lepida, are very close to Ginkgoites s i b i r i c a , (especially f i g . 6 of Fontaine's) except that Fontaine's material has a greater number of lobes, a feature of doubtful s p e c i f i c s i g n i f i c a n c e . The strong resemblance of Sagenopteris g r a n d i f o l i a Fontaine (in Ward, 1905, p l . 15, f i g . 4, 5) to Sagenopteris W i l l i a m s i of the Hazelton f l o r a has already been ci t e d by W.A.Bell (1956i p. 8 0 ) . Specimens referred by Fontaine to Pterophyllum  continuum ( i n Ward, 1905, p. 99, p l . 19, f i g . 7-11) are accord-ing to B e l l (1956, p. 95) possibly conspecific with Ptilophyllum arcticum i n the Hazelton f l o r a . B e l l (1956, p. 96) c i t e s Ptilophyllum cqli^bianum of the Hazelton f l o r a as bearing a close resemblance to Pterophyllum aequale Fontaine ( i n Ward, 1905, p l . 2 0 ) . Fontaine's example of Cladophlebis denticulata ( i n Ward, 1905, plate 11, f i g . 7) with entire margins i s not unlike forms of Cladophlebis v i r g i n i e n s i s i n the writer's c o l l e c t i o n of Hazelton plants. N i l s s o n i a canadensis of the Hazelton f l o r a ( i n B e l l , 1956, p. 104) is'comparable with forms referred by Fontaine to Taeniopteris o r o v i l l e n s i s (in Ward, 1905, p. 78, 79, plate 12, f i g . 12-17) , the only difference being that i n the Oregon form the veins are somewhat curved. From the foregoing l i s t , i t can be noted that 9 species from the Riddle Formation are considered s p e c i f i c a l l y i d e n t i c a l with counterparts from the Hazelton. This has been done care-f u l l y and cautiously because of the inferences this has i n dating, but the writer i s confident of the accuracy of the i d e n t i f i c a t i o n s and comparisons. Comparison with Potomac Flora The Potomac Group of Maryland and V i r g i n i a contains an extensive f l o r a t o t a l l i n g 174 species (Dorf, 1952, p. 2165,2166). This f l o r a i s contained i n three formations comprising the 31 Potomac Group,, namely, the Patuxent of Neocomian age, the Arundel of Neocomian age and the Patapsco of Albian age. This f l o r a contains the following species that are also found i n the Hazelton f l o r a . Where a Potomac species d i f f e r s i n name from the Hazelton equivalent, the Hazelton species i s given i n brackets. Ruffordia goepperti. Onychiopsis b r e v i f o l i a (Coniopteris b r e v i f o l i a ) . Equisetum l y e l l i (Equisetites l y e l l i ) . Gleichenites nordenskioldi. Podozamites laneeolatus. Cladophlebis v i r g i n i e n s i s . Cladophlebis parva. Sphenopteris dentata. The f i r s t four species i n the above l i s t occur only i n the Patuxent formation, whereas the f i f t h species above (Podozamites laneeolatus) occurs i n the Patuxent and Patapsco formations. The l a s t three species range from the Patuxent through the Patapsco Formation. If t h i s f l o r a i s considered as a whole, i t has a 2 0 . 5 $ c o r r e l a t i o n with the Hazelton f l o r a . The $ corr e l a t i o n i s much less for the Arundel and Patapsco f l o r a s i f each f l o r a i s considered separately; v i z , Patuxent, 2 0 . 5 $ , Arundel, 7 . 6 $ , Patapsco 1 0 . 2 $ . 32 Comparison with the F l o r a of the Kootenay Formation W.A.Bell ( 1 9 5 6 , f i g . 1) l i s t s a t o t a l of 33 plant species i n the Kootenay f l o r a , of which 21 are i d e n t i f i e d s p e c i f i c a l l y . The following species from the Kootenay also occur i n the Hazelton f l o r a . Where a Kootenay species d i f f e r s i n name from the Hazelton equivalent, the Hazelton species i s given in brackets. Coniopteris b r e v i f o l i a . Cladophlebis v i r g i n i e n s i s . Cladophlebis heterophylla. Sphenopteris l a t i l o b a (Sphenopteris dentata). Equisetites l y e l l i . Baiera c f . furcata. Baiera c f . gracilus . Ginkgo p l u r i p a r t i t a (Ginkgoites a r c t i c u s ) . Ginkgo c f . lepida (Ginkgoites s i b i r i c a ) . Czekanowskia cf. r i g i d a . Ptilophyllum (Anomozamites) montanense. Ptilophyllum arcticum. N i l s s o n i a s chaumb urgensis. N i l s s o n i a n i g r a c o l l e n s i s (Nilssonia parvula). Nil s s o n i a canadensis. Pseudoctenis hazeltonensis. Pityopnyllum c f . nordenskioldi. Podozamites lanceolatus. These 19 species provide a 73 .0% c o r r e l a t i o n with the 33 Hazelton f l o r a . As pointed out previously i n the section on i d e n t i f i -cations, the following synonymies occur i n the foregoing l i s t : Sphenopteris l a t i l o b a for Sphenopteris den tat a, Ginkgo, p 1 uripart±t a for Ginkgoites a r c t i c u s , Ginkgo_ nana for Ginkgoites s i b i r i c a , and N i l s s o n i a n i g r a c o l l e n s i s for N i l s s o n i a  parvula. The Kootenay species Ginkgo c f . lepida (in B e l l , 1956, p. 87, p l . 37, f i g . 5) d i f f e r s i n no s i g n i f i c a n t respects from forms referable to Ginkgoites s i b i r i c a . As pointed out by Seward (1919, p. 11) an increase i n the number of lobes i s not considered to be a feature for s p e c i f i c d i s t i n c t i o n . Comparison with the Flo r a of the BlaiEmore Group Lower F l o r a : The Blairmore "lower f l o r a " comprises 37 plant species ( B e l l , 1956, f i g . 1). 33 of the species are i d e n t i f i e d s p e c i f i c a l l y . The following species also occur i n the Hazelton f l o r a l Where a lower Blairmore species d i f f e r i n name from the Hazelton equivalent, the Hazelton species is given i n brackets. Coniopt er i s brev i f o l i a . Cladophlebis v i r g i n i e n s i s . Cladophlebis parva. Klukia canadensis. Sphenopteris (Ruffordia) goppert!. Sphenopteris l a t i l o b a (Sphenopteris dentata). Equisetites l y e l l i . Sagenopteris Williamsi. Ginkgo p l u r i p a r t i t a (Ginkgoites a r c t i c u s ) . Ginkgo nana (Gingoites s i b i r i c a ) . Phoenicopsis a r c t i c a . Ptilophyllum (Anomozam11es) montanense. Ptilophyllum arcticurn. Pseudocycas dunkeriana. M l s s o n i a canadensis. Elatides c u r v i f o l i a . Pityophyllum cf. nordenskioldi. Podozamites lanceolatus. These 18 species res u l t i n a 5 0 . 0 $ c o r r e l a t i o n with the Hazelton f l o r a . The synonymies for those names i n the above l i s t that d i f f e r from names i n the Hazelton f l o r a , have been pointed out i n the previous section and elsewhere i n this paper, and need not be repeated here. The most noteworthy feature of the Blairmore "lower f l o r a " i s the presence of one dicotyledon, Sapindopsis angusta ( B e l l , 1 9 5 6 , p. 1 1 ) . This species also occurs i n the Blairmore "upper f l o r a " which w i l l be compared with the Hazelton f l o r a i n the next section. Upper Fl o r a : The "upper f l o r a " of the Blairmore group contains a t o t a l of 35 plant species ( B e l l , 1 9 5 6 , f i g . 1) of which 18 are s p e c i f i c a l l y i d e n t i f i e d . The following species also occur i n the Hazelton f l o r a : Cladophlebis v i r g i n i e n s i s . Equisetites l y e l l i . These two plants constitute a 10.0% correlation with the Hazelton f l o r a . The most s i g n i f i c a n t feature of the Blairmore "upper f l o r a " i s the presence of 9 dicotyledons, whereas none i s re-ported from the Hazelton f l o r a . PART I I I - INTERPRETATION OF RESULTS The f l o r a s of the Riddle and Kennecott formations are the only f l o r a s , i n the previous section, which have the f l o r a l datings substantiated by faunal datings. In the case of the f l o r a of the Kennecott Formation, at least three molluscan assemblages are present (Imlay et a l , 1954-) which can be correlated with certainty with beds of the Albian of the l a t e s t early Cretaceous i n C a l i f o r n i a , i n the Queen Charlotte Islands, and i n Europe. In sharp contrast to the foregoing evidence of the age of the Kennecott formation, Knowlton ( i n Martin, 1926, p. 344-346) was quite d e f i n i t e that the age of the Kennecott Formation i s either l a t e Jurassic or e a r l i e s t Cretaceous. Hox^ever, the overwhelming faunal evidence together with the generally acknow-ledged fact that faunas take precedence over fl o r a s for dating, makes i t apparent that Knowlton, although his i d e n t i f i c a t i o n s of 36 t h e p l a n t s a r e u n d o u b t e d l y c o r r e c t , has d a t e d the f l o r a s l i g h t l y too o l d . The J u r a s s i c f l o r a o f Douglas County, Oregon, has s i n c e 1905 ( F o n t a i n e , i n Ward) been a c c e p t e d as a J u r a s s i c f l o r a . However, the e x a c t r e l a t i o n s h i p s o f t h e p l a n t - b e a r i n g beds t o the o v e r l y i n g and u n d e r l y i n g s t r a t a have been i n doubt u n t i l r e c e n t l y . Recent work by R.W. Imlay et a l (1959) has shown t h a t the p l a n t s a r e c o n t a i n e d i n the R i d d l e F o r m a t i o n ( r e d e f i n e d ) , and t h a t t h i s u n i t a l s o c o n t a i n s f o s s i l s o f l a t e J u r a s s i c ( P o r t l a n d i a n - m i d d l e to l a t e T i t h o n i a n ) age. The R i d d l e F o r m a t i o n r e s t s w i t h a n g u l a r u n c o n f o r m i t y on the o l d e r J u r a s s i c Galic'e, Rogue, and Dothan f o r m a t i o n s . The Days Creek F o r m a t i o n r e s t s c o n c o r d a n t l y on t h e R i d d l e F o r m a t i o n and l o c a l l y o v e r l a p s onto o l d e r J u r a s s i c r o c k s . The c o n t a c t between the R i d d l e and o v e r l y i n g Days Creek F o r m a t i o n i s c o n s i d e r e d to be a d i s c o n f o r m i t y i n v o l v i n g the B e r r i a s i a n and p a r t o f the V a l a n g i n i a n s t a g e s . Imlay (1959, p. 278O) i n r e f e r e n c e to t h e p l a n t s says: "The e v i d e n c e based on m o l l u s k s shows t h a t the p a l e o b o t a n i s t s were c o r r e c t i n t h e i r J u r a s s i c age assignments o f c e r t a i n p l a n t s , but t h a t t h e p a r t i c u l a r beds i n Douglas County, Oregon, i n w h i c h the p l a n t s o c c u r a r e l a t e s t J u r a s s i c r a t h e r t h a n M i d d l e J u r a s s i c . " K nowlton (1910, p. 145) thought t h a t the p l a n t s were as o l d as the Lower O o l i t e ( B a j o c i a n ) o f Europe. The Corwin F o r m a t i o n o f n o r t h w e s t e r n A l a s k a c o n t a i n s , i n a d d i t i o n to the J u r a s s i c f l o r a o f Cape L i s b u r n e ( K n o w l t o n , 1914), 37 a younger f l o r a at i n l a n d exposures that has been dated from E a r l y to Late Cretaceous by s e v e r a l authors ( i n Chapman and S a b l e , i960, p. 125). Attempts to c o r r e l a t e the i n l a n d exposures w i t h the c o a s t a l ones, on the b a s i s of s i m i l a r l i t h o l o g i e s and s t r u c t u r a l c o n t i n u i t y , do not appear to be e n t i r e l y c o n c l u s i v e . In view of the d i s c r e p a n c y i n the ages o f the i n l a n d and c o a s t a l exposures, which are based e n t i r e l y on f o s s i l p l a n t s , the w r i t e r does not propose to d i s c u s s f u r t h e r the Cape L i s b u r n e or i n l a n d f l o r a s . At the present time, the l o c a t i o n of the J u r a s s i c -Cretaceous boundary i n western Canada and i n p a r t i c u l a r the age of the Kootenay and B l a i r m o r e formations are problems about which there i s c o n s i d e r a b l e c o n t r o v e r s y (Pocock, I960,' p. 9) 10; Gussow, I960). I n s p e c t i o n of f i g u r e 3 and of the comparisons o f the Hazelton f l o r a w i t h other f l o r a s made i n the p r e v i o u s s e c t i o n , i n d i c a t e that the Hazelton f l o r a has i t s s t r o n g e s t c o r r e l a t i o n s w i t h the f l o r a of the R i d d l e Formation, the Kootenay f l o r a , and the lower B l a i r m o r e f l o r a . Consequently any assignment o f an age to the Hazelton f l o r a depends to a c o n s i d e r a b l e extent on the ages of these three f l o r a s , p a r t i c u l a r l y the ages o f the Kootenay and lower B l a i r m o r e f l o r a s . The ages of these l a s t 2 f l o r a s are not e s t a b l i s h e d c o n c l u s i v e l y . I t i s observed i n f i g u r e 4 and a previous s e c t i o n o f t h i s t h e s i s that the Hazelton f l o r a has few s i m i l a r i t i e s of importance w i t h the Cape L i s b u r n e , Kennecott, and Upper B l a i r -more f l o r a s . In so f a r as the Cape L i s b u r n e and Kennecott 38 f l o r a s are concerned t h i s i s undoubtedly due i n part to the small number of plants that comprise these f l o r a s . It i s observed i n figure 4 that only 2 species i n the Hazelton f l o r a occur also in the upper Blairmore f l o r a r e s u l t -ing i n a 10 .0% c o r r e l a t i o n . This very low c o r r e l a t i o n , to-gether with the presence of 9 dicotyledons i n the upper B l a i r -more f l o r a (whereas no dicotyledons occur i n the Hazelton f l o r a ) makes i t apparent that these.two flo r a s are d e f i n i t e l y not c o r r e l a t i v e . Eighteen species i n the Hazelton f l o r a also occur i n the lower Blairmore f l o r a , as pointed out e a r l i e r , r e s u l t i n g i n a 5 0 . 0 % c o r r e l a t i o n . Probably the most s i g n i f i c a n t aspect of a f l o r a to be considered when assigning an age, i s the introduction of new species. Therefore, the presence of a dicotyledon, Sapindopsis angusta i n the lower Blairmore f l o r a assumes prime importance. The presence of this dicotyledon In the lower Blairmore f l o r a (and the complete absence of dicoty-ledons i n the Hazelton f l o r a ) , together with the absence of such c h a r a c t e r i s t i c Jurassic species as Coniopteris hymenophylloides, Baiera cf. furcata, Baiera cf. g r a c i l u s , etc., (which are present i n the Hazelton f l o r a ) i s considered s u f f i c i e n t evidence to preclude a close co r r e l a t i o n of these two f l o r a s for purposes of assigning an age. However, the r e l a t i v e l y high % c o r r e l a t i o n indicates a general syngenetic relationship of the 2 f l o r a s . The f l o r a of the Riddle Formation and the f l o r a of the Potomac Group are the only two major Jurassic-Cretaceous f l o r a s i n North America that are well dated; the Kennecott has been accurately dated but contains a r e l a t i v e l y small f l o r a . Although the Potomac f l o r a i s an "accepted" Lower Cretaceous f l o r a , there i s apparently some doubt as to the ages of the three f l o r a s comprising the o v e r a l l Potomac f l o r a , and hence of the three formations (Patuxent, Arundel, and Patapsco) comprising the Potomac Group. Some discussion on this problem is given by B e l l (1956, p.12), who i n discussing the age of the lower B l a i r -more f l o r a and the presence of 15 lower Blairmore species i n the Potomac f l o r a says: "If the Patuxent and Arundel were deposited within the Neocomian-Barremian time unit as thought by Berry (1911, p. 172) an explanation for the occurrence of the Aptian lower Blairmore species, Gleichenites nordenskioldi, Elatocladus b r e v i f o l i a and Elatocladus a c i f o l i a , i n the supposedly Neo-comian Patuxent formation might be attributed to the distance between the occurrences. On the other hand, there i s a p o s s i b i l i t y that the Patuxent and Arundel f l o r u l e s may be as young as Aptian. Dorf (1952, p. 2176) has recorded E.H. Colbert's summary of the age significance of Arundel dinosaurs as possibly pointing to 'a high stage in the Lower Cretaceous 1X" Eight species i n the Hazelton f l o r a also occur i n the f l o r a of the Potomac Group, r e s u l t i n g i n a 20.5$ c o r r e l a t i o n , as has been pointed out in the previous section. This $ cor r e l a t i o n figure includes species and " c f " forms. I f , however, only well defined species are considered, the Hazelton f l o r a has a 22.8$ c o r r e l a t i o n with the Potomac f l o r a . 40 I f t h e Potomac f l o r a i s d i v i d e d i n t o t h r e e sub f l o r a s w i t h r e s p e c t to the t h r e e f o r m a t i o n s ( P a t u x e n t , A r u n d e l , and P a t a p s c o ) c o m p r i s i n g t h e Potomac Group th e n the % c o r r e l a t i o n w i t h any one sub f l o r a becomes much l e s s . Of the e i g h t H a z e l -t o n s p e c i e s o c c u r r i n g i n the Potomac Group f o u r o f them ( R u f f o r d i a g o e p p e r t i , O n y c h i o p s i s b r e v i f o l i a , Equisetum l y e l l i and G l e i c h e n i t e s n o r d e n s k i o l d i ) o c c u r o n l y i n the P a t u x e n t F o r m a t i o n o f supposed Neocomian age. One s p e c i e s (Podozamites  l a n e e o l a t u s ) o c c u r s i n b o t h the P a t u x e n t and P a t a p s c o f o r m a t i o n s , and t h r e e s p e c i e s ( C l a d o p h l e b i s v i r g i n i e n s i s , C l a d o p h l e b i s p a r v a , and S p h e n o p t e r i s d e n t a t a ) o c c u r o n l y i n t h e A r u n d e l F o r m a t i o n o f presumed Neocomian age. C o n s i d e r i n g s p e c i e s o n l y t h e n , t h e H a z e l t o n f l o r a has the f o l l o w i n g % c o r r e l a t i o n s w i t h the t h r e e sub f l o r a s o f the Potomac Group: P a t a p s c o 8.7% A r u n d e l 8.5% P a t u x e n t 22.8% These v e r y low % c o r r e l a t i o n s , t o g e t h e r w i t h t h e f o l l o w i n g d a t a , s e r v e t o p o i n t out t h a t a c l o s e c o r r e l a t i o n o f t h e s e f l o r a s w i t h the H a z e l t o n f l o r a i s not p o s s i b l e w i t h any c o n f i d e n c e : (a) The absence i n t h e Potomac f l o r a o f the J u r a s s i c element p r e s e n t i n the H a z e l t o n f l o r a , i . e . , C o n i o p t e r i s  h y m e n o p h y l l o i d e s , Czeckanowskia c f . r i g i d a , s p e c i e s o f B a i e r a , e t c . ) ; (b) The presence o f 6 (out o f 111) angiosperm s p e c i e s 41 i n the Patuxent f l o r a , 5 (out o f 37) i n the Arundel f l o r a , and 25 (out of 91) i n the Patapsco f l o r a , whereas the Hazelton f l o r a i s c h a r a c t e r i z e d by the complete absence o f angiosperms. The f l o r a o f the R i d d l e Formation i n Douglas County, Oregon, contains 9 s p e c i e s that occur a l s o i n the Hazelton f l o r a . These 9 s p e c i e s r e s u l t i n a 25.6$ c o r r e l a t i o n between the two f l o r a s . I f sp e c i e s and ''cf" forms are con s i d e r e d i n the comparison, however, the $ c o r r e l a t i o n i s i n c r e a s e d s h a r p l y to 46.1$. T h i s s t r o n g s t a t i s t i c a l c o r r e l a t i o n w i t h a w e l l - d a t e d f l o r a of l a t e J u r a s s i c age, together w i t h the complete absence of d i c o t y l e d o n s i n these f l o r a s and the presence i n the Hazelton f l o r a o f such c h a r a c t e r i s t i c J u r a s s i c s p e c i e s as Coniopt er i s hy_menqphy 1 l o i d e s , N i l s s o n i a pterqphylloid.es, Pterophyllum t e n n u i p i n n a t u s , B a i e r a c f . f u r c a t a , B a i e r a c f . g r a c i l u s , N i l s s o n i a p a r v u l a and Czeckanowskia c f . r i g i d a p o i n t s t r o n g l y to the acceptance of a l a t e J u r a s s i c age, i n pa r t at l e a s t , f o r the Hazelton f l o r a . In comparing f l o r a s the words of A.C. Seward (1900, p. 3025 are worthy o f note: "In the comparison of f l o r a s more or l e s s w i d e l y separated g e o g r a p h i c a l l y , the r e c o g n i t i o n o f s p e c i f i c i d e n t i t y i s n a t u r a l l y d e s i r a b l e , but the o b j e c t of a comparative study o f f o s s i l f l o r a s i s p r i m a r i l y to determine the resemblances and d i f f e r e n c e s as regards the g e n e r a l f a c i e s o f the v e g e t a t i o n r a t h e r than the a b s o l u t e s p e c i f i c i d e n t i t y of i n d i v i d u a l p l a n t s . " 42 Fourteen species of plants are common to both the Hazelton and Kootenay f l o r a s r e s u l t i n g i n a 6 6 . 6 % c o r r e l a t i o n . I f " c f " forms are included, then the % corr e l a t i o n i s increased to 7 3 . 0 % . The l i s t of species common to both floras has been given i n the previous section and w i l l not be repeated here. The age of the Kootenay f l o r a i s to some extent de-pendent on the ages of the lower Blairmore and upper Blairmore f l o r a s , the ages of which depend to a considerable extent on the age of the Potomac f l o r a s . Hence i t i s observed that the ages of the 3 Potomac f l o r a s , though apparently not established con-c l u s i v e l y , have considerable significance i n the present d i s -cussion. The following s i x species i n the Kootenay f l o r a occur also i n the Potomac f l o r a ( B e l l , 1 9 5 6 , p . 7 ) : Cladophlebis v i r g i n i e n s i s . Sphenopteris l a t i l o b a . Onychiopsis p s i l o t o i d e s . Coniopteris b r e v i f o l i a . Equisetites l y e l l i . Podozamites lanceolatus. It i s observed that a l l the foregoing species occur also in the Hazelton f l o r a . These 6 species give the Kootenay f l o r a a 28.5% c o r r e l a t i o n with the Potomac f l o r a . As pointed out e a r l i e r , the Hazelton f l o r a has 8 species common to the Potomac f l o r a for a 22.8% c o r r e l a t i o n . I f however, "cf" forms are i n c l u d e d f o r a $ c o r r e l a t i o n f i g u r e , t h e $ c o r r e l a t i o n i s r e -duced to 2 3 . 5 $ f o r the Kootenay and 2 0 . 5 $ f o r the H a z e l t o n f l o r a The f o l l o w i n g 8 s p e c i e s o f the Kootenay f l o r a o c c u r a l s o i n the f l o r a o f the R i d d l e F o r m a t i o n . Where an Oregon s p e c i e s d i f f e r s in.name from the Kootenay e q u i v a l e n t , the Kootenay s p e c i e s i s g i v e n i n b r a c k e t s . N i l s s o n i a p a r v u l a ( N i l s s o n i a n i g r a c o l l e n s i s ) . T a e n i o p t e r i s o r o v i l l e n s i s ( N i l s s o n i a c a n a d e n s i s ) . C l a d o p h l e b i s v a c c e n s i s ( C l a d o p h l e b i s v i r g i n i e n s i s p a r s . ) Ginkgo d i g i t a t a ( G i n k g o i t e s a r c t i c u s ) . Ginkgo s i b i r i c a (Ginkgo nana. Ginkgo c f . l e p i d a ) . P t e r o p h y l l u m contiguum (P t i l o p hy1lum a r c t i c u m ) . Podozamites l a n e e o l a t u s . P i t y o p h y l l u m c f . n o r d e n s k i o l d i . These 8 s p e c i e s r e s u l t i n a 3 2 . 5 $ c o r r e l a t i o n o f the Kootenay w i t h the Oregon f l o r a ( 4 6 . 1 $ f o r the H a z e l t o n f l o r a ) . I f , however, s p e c i e s o n l y a r e c o n s i d e r e d , then the $ c o r r e l a t i o n o f the Kootenay w i t h t h e Oregon f l o r a i s reduced t o 1 4 . 3 $ ( 2 5 . 7 $ f o r t h e H a z e l t o n f l o r a ) . B e l l ( 1 9 5 6 , p . 7 ) s i t e s 6 s p e c i e s i n the Kootenay f l o r a w h i c h a r e c h a r a c t e r i s t i c J u r a s s i c s p e c i e s . At the bottom o f the same page B e l l s t a t e s : "The o c c u r r e n c e o f such c h a r a c t e r i s t i c Wealden s p e c i e s as S p h e n o p t e r i s c o r d a i , O n y c h i o p s i s  p s i l o t o i d e s and N i l s s o n i a schaumburgensis i s con s i d e r e d t o be s u f f i c i e n t e v i d e n c e t o d a t e the Kootenay f l o r a as e a r l y C r e t a c e o u s and f a l l i n g w i t h i n the time u n i t f o r I n f r a v a l a n g i n i a n to B a r r e m i a n i n c l u s i v e . " 44 The w r i t e r most c e r t a i n l y agrees that these are char-a c t e r i s t i c Wealden s p e c i e s . Using t h i s same method o f r e a s o n i n g , however, one could argue j u s t as s t r o n g l y f o r an Upper J u r a s s i c age f o r the Kootenay f l o r a based on the J u r a s s i c element i n t h i s f l o r a , e.g., Czeckanqwskia c f . r i g i d a , B a i e r a c f . F u r c a t a , N i l s s o n i a p a r v u l a , Podozamites l a n e e o l a t u s and some forms o f C l a d o p h l e b i s v i r g i n i e n s i s pars (=C.den 1 1culata). Presumably, the hypothesis behind the argument presented by B e l l i s that new s p e c i e s are c h a r a c t e r i s t i c a l l y superimposed on s p e c i e s c a r r y -i n g over from o l d e r f l o r a s . I f t h i s i s so, then i t indeed en-hances an argument f o r a lowermost Cretacous age. CONCLUSIONS A lower l i m i t f o r the age of the "upper sedimentary u n i t , " i n the Smithers a r e a at l e a s t , has been e s t a b l i s h e d by F.H.McLearn (1926, p. 89) who i d e n t i f i e d a fauna from the u n d e r l y i n g sedimentary u n i t as being o f Late S o n n i n i a n to E a r l y Steppheoceratan or Middle B a j o c i a n age. As a r e s u l t , the Hazelton f l o r a may be as o l d as O x f o r d i a n or C a l l o v i a n . At t h i s p o i n t i t i s p e r t i n e n t to comment on the apparent c o n f l i c t s between f o s s i l faunas and p l a n t s i n both the Hazelton and Smithers map area. Armstrong (1953) i n the d e s c r i p t i v e notes on the Hazelton map s t a t e s : 45 " F o s s i l fauna were collected from at least twenty-l o c a l i t i e s , but only two of the col l e c t i o n s con-tained diagnostic specimens. These are of la t e Upper Jurassic age. They were collected from beds that apparently l i e s t r a t i g r a p h i c a l l y above beds containing f o s s i l plants of Kootenay age." Dr. Armstrong (personal communication) stated that the i d e n t i f i c a t i o n of this fauna was done by F.H.McLearn. It would appear then that i n this instance the plants were dated too young, since there i s no evidence to indicate that the strata in question are overturned. In the descriptive notes on the Smithers map-area, Armstrong (1944) states: "In Glacier Gulch, however, f o s s i l shells of Upper Jurassic or very early Lower Cretaceous age were collected from a bed 300 feet s t r a t i g r a p h i c a l l y above a bed containing f o s s i l plants of Blairmore age." This fauna was i d e n t i f i e d by F.H.McLearn (J. E. Armstrong, personal! communication). Since some controversey (see B e l l , 1 9 5 6 , p.24) prevails about the stratigraphy i n t h i s area, the writer does not propose to discuss the problem any further. In an attempt to determine how many Hazelton species occur i n Jurassic areas and how many i n Lower Cretaceous (Wealden) areas the following table was compiled. The Hazelton f l o r a was compared with the Potomac, Oregon Jurassic, Kennecott, Yorkshire Jurassic, and English Wealden f l o r a s . To supplement data from these comparisons, use was made of Seward's 4 volumes on f o s s i l plants. TABLE I I I Hazelton Species Equisetites l y e l l i  Cladophlebis heterophylla C. impressa C. parva C. v i r g i n i e n s i s Coniopteris b r e v i f o l i a C. hym e no p hy 11 o i d e s Dictyophy11urn fuchsiforme Gleichenites nordenskioldi  Klukia canadensis  Sphenopteris acrodentata S. dentata (Ruffordia) gopperti  Sagenopteris Wi l l i a m s 1 Ctenopteris insig n i s N i l s s o n i a brongniarti N. canadensis N. parvula N. pterophylloides N. schaumbur g ens i s Pseudoctenis hazeltonensis  Pseudocycas dunkeriana  Pterophyllum tennuipinnatus P. rectangulare Jurassic X X X X X X X Lower Cretaceous (Wealden) X X X X X X X X X X 47 Hazelton Species Jurassic Lower Cretaceous (Wealden) Ptilophyllum arcticum P. Columbianurn P. Hirtum P. (Anomazamites) montanense Baiera sp. cf. furcata B_aiera. sp. cf. gracilus Ginkgoites arcticus G. s i b i r i c a  Athrotaxites b e r r y i  Elatides c u r v i f o l i a  Elatides splendida  Pityophyllum cf. nordenski51di  Czekanowskia sp. cf. r i g i d a  Phoenicopsis a r c t i c a Podozamites lanceolatus X X X X X X X X X X X X X 48 From the foregoing table i t i s observed that 18 species occur i n Jurassic areas and 14 occur i n Lower Cretaceous areas. Seven species occur i n both Jurassic and Lower Cretaceous areas. This data i s s u f f i c i e n t to indicate that the Hazelton f l o r a i s undoubtedly a t r a n s i t i o n a l f l o r a between the Jurassic and Cretaceous. It i s considered that the Hazelton f l o r a , and the "upper sedimentary unit" i n which i t i s contained, can be dated with confidence as late Jurassic to early Cretaceous, that i s , Portlandian to Neocomian inc l u s i v e because of the following: (1) A strong s t a t i s t i c a l c o r r e l a t i o n (46.1%) with the f l o r a of the Riddle Formation i n Douglas County, Oregon. (2) The presence of an undoubted Jurassic element in the Hazelton f l o r a . (3) The presence of 6 angiosperms out of 111 species i n the Patuxent Formation (Neocomian), whereas none occurs i n the Hazelton f l o r a . This would suggest an age assignment of younger than Purbeckian (Uppermost Jurrasic) cannot be made for the Hazelton f l o r a . However, according to Axelrod (1959) angio-sperms i n i t i a l l y invaded lowland basins at generally lower l a t i t u d e s , and appeared i n the record at higher latitudes only i n the l a t e r part of the Early Cretaceous. If this i s indeed the case, then the Hazelton f l o r a may be Neocomian when com-pared to the lower Blairmore (Aptian) f l o r a with i t s one dicotyledon. 49 (4) The wide ranging nature of some of the f o s s i l plants under consideration suggests the p o s s i b i l i t y of the assignment of an Early Cretaceous age to the Hazelton f l o r a , e « g « j Ginkgoites s i b i r i c a , Elatides curv i f o l i a , Pityophyllum  nordenskioldi, N i l s s o n i a parvula, Podozamites lanceolatus. (5) The presence of shells of Upper Jurassic age in the Hazelton area at two l o c a l i t i e s . ( 6 ) The presence i n the Hazelton f l o r a of c h a r a c t e r i s t i c Lower Cretaceous species such as N i l s s o n i a schaumburgensis, (Ruffordia) gopperti, and Coniopteris b r e v i f o l i a . It i s considered probable that the Hazelton f l o r a does not range through the entire Neocomian, but rather that i t may be r e s t r i c t e d to the lower half of the Neocomian epoch. Evidence for this consists of the following: (1) Presence of a strong Jurassic element in the Hazelton f l o r a ; (2) Absence of angiosperms i n the Hazelton f l o r a and the presence of them i n the Patuxent and Arundel f l o r a s which apparently represent part of the Neocomian, and presumably the la t e r part; (3) Absence i n the Patuxent and Arundel f l o r a s of many of the c h a r a c t e r i s t i c Jurassic species which are present i n the Hazelton f l o r a . Future Work: Suggestions for further work on the age of the "upper 50 s e d i m e n t a r y u n i t " and t h e H a z e l t o n Group i n g e n e r a l , i n c l u d e t h e f o l l o w i n g : (1) A d d i t i o n a l c o l l e c t i n g o f f o s s i l p l a n t s and f a u n a s t o a i d i n t h e s t u d y o f t h e s t r a t i g r a p h y and a l s o i n a s s i g n i n g c o n c l u s i v e ages t o t h e u n i t s c o m p r i s i n g t h e H a z e l t o n G r o u p . I n t h i s r e g a r d t h e p o s s i b i l i t y o f h a v i n g J u r a s s i c f l o r a s o f more t h a n one age s h o u l d be c o n s i d e r e d . A n o t h e r f e a t u r e w i t h r e g a r d t o t h e p l a n t f o s s i l s i s t h e u n l i k e l i h o o d o f c u t i c l e work b e i n g o f any use due t o t h e metamorphism o f t h e r o c k s and t h e c o n t a i n e d l e a v e s . (2) F o s s i l p l a n t c o l l e c t i o n s s h o u l d , i f p o s s i b l e , be t a k e n t o E u r o p e and t h e U n i t e d S t a t e s and compared d i r e c t l y w i t h t y p e specimens ' . ( 3 ) F u r t h e r c o l l e c t i o n s o f s a m p l e s f o r p l a n t m i c r o -f o s s i l a n a l y s i s s h o u l d be made, as d i s c u s s e d e a r l i e r . (4) C o n s i d e r a t i o n s h o u l d be g i v e n t o t h e p o s s i b i l i t y o f u s i n g o t h e r methods f o r d a t i n g ; e g . p o t a s s i u m - a r g o n . 51 PLATE I Figure 12 Figure 9.W Figure 11 Figure 10.W Figure 5* Figure 4 Figure 7 Figure 1 Figure 2 Figure 8 (Photographs are natural s i z e ; scale divisions are i n mm.) Equisetites l y e l l i (Mantell) Unger. Cladophlebis heterophylla Fontaine. ? Cladophlebis (Gleichenites) p o r s i l d i Seward. Coniopteris (Sphenopteris) hymenophylloides (Brongniart) Seward. Sphenopteris dentata (Velonovsky) Seward. Nilssonia parvula (Heer) Fontaine. Nilssonia pterophylloides Nathorst. Pterophyllum tennuipinnatus n.sp. ("type specimen B-3407).~ ~ Pterophyllum tennuipinnatus n.sp. (counterpart B - 3 3 9 9 ) . Ptilophyllum arcticum (Goppert) Seward. PLATE I I (Photographs are natural size unless otherwise indicated, scale d i v i s i o n s are i n mm.) Figure 15 Baiera sp. c f . furcata (Lindley and Hutton) Braun. Figure 3 Ginkgoites arcticus (Heer) F l o r i n . Figure 13 Elatides c u r v i f o i i a (Dunker) Nathorst. Figure 6 Ginkgoites s i b i r i c a Heer Figure 16 Baiera sp. c f . gracilus (Bean) Bunberry. Figure 17 Czekanowskia sp. cf. r i g i d a Heer (X^) Figure 14 Coniopteris b r e v i f o l i a (Fontaine) B e l l (X 4). 53 BIBLIOGRAPHY Anderson, P.M., 1938, Lower Cretaceous Deposits i n C a l i f o r n i a and Oregon: Geol. Soc. America Spec. Paper 16, 328 p., 84 p i s . , 3 f i g s . Andrews, H.N., J r . , 1955? Index of Generic Names of F o s s i l Plants, 1820-1950: U.S.Geol. Survey B u l l . 1013, 262 p. A r k e l l , 1933, Jurassic System i n Great B r i t a i n : Oxford at the Clarendon Press, 671 p., 41 p i s . - - - - 1956, Jurassic Geology of the World: Oliver and Boyd Limited, Edinburgh, London, 805 p., 46 p i s . Armstrong, J.E., 1944, Preliminary Map Smithers, B r i t i s h Columbia: Geol. 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