UBC Theses and Dissertations

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UBC Theses and Dissertations

Ore Deposits of the Eastern side of the Coast Range Batholith (with special reference to Atlin District.) Okulitch, Vladimir J. 1932

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1. Ore Deposits of the Eastern side of the Coast Range i i a t h o l i t h (with s p e c i a l reference  to A t l i n D i s t r i c t . )  by  Vladimir J. Okulitch  B. A.  Sc.  Thesis s u b m i t t e d f o r the degree of s/aster of Applied  Department of Geology F a c u l t y of Atsoliea Science. The U n i v e r s i t y of B r i t i s h Columbia. April,  1932.  Science.  2.  Table o f Contents* Page.  4  Foreword. Part  1.  Introau.eti.on and Summary.  &  (a) Topography and p h y s i o g r a p h y .  7  (b) G e n e r a l g e o l o g y .  8  (c) Economic g e o l o g y .  il  Part 1.  Topography and P h y s i o g r a p h y .  19  (a) The Coast Range.  £1  (b) I n t e r i o r P l a t e a u System.  22  (0)  24  T r a n s i t i o n a l Zone.  £.  B r i e f Geological History  3.  General  4.  2.  2?  Geology.  (a) The Coast Range B a t h o l i t h .  30  (b) T a b l e o f F o r m a t i o n s .  39  (c) D e s c r i p t i o n o f F o r m a t i o n s .  39 54  Economic Geology. (a) D e s c r i p t i o n o f Ore D e p o s i t s .  P a r t 3. 1.  Topography and P h y s i o g r a p h y .  2.  G e n e r a l Geology. (a) T a b l e o f f o r m a t i o n s (b) D e s c r i p t i o n o f f o r m a t i o n s .  3.  Economic  (Atlin District)  95 o£ 101  -  102 1Q4  Geology.  (a) G e r i e r a l .  Hj  Page. (b) D e s c r i p t i o n o f Ore  Part  Deposits.  117  4. 158  Bibliography.  Appendix.  Foreword. T h i s t h e s i s i s d i v i d e r i n t o two p a r t s .  The  first  d e a l s w i t h the e n t i r e a r e a under c o n s i d e r a t i o n , w h i l e second d e s c r i b e s the A t l i n d i s t r i c t . necessary  the  T h i s d i v i s i o n was  because of the g r e a t e r f a m i l i a r i t y o f the  deemed  author  w i t h the A t l i n d i s t r i c t , where he s p e n t two summers d o i n g g e o l o g i c a l work, f o r a m i n i n g  company.  Thus the ,-i.tlin d i s t r i c t  i s d e s c r i b e d i n a g r e a t e r d e t a i l than i t was  p o s s i b l e to des-  c r i b e the r e s t o f the a r e a , where t h e o n l y s o u r c e s m a t i o n were r e p o r t s and o f Canada, and The  of  infor-  the memoirs of the G e o l o g i c a l Survey  the M i n i s t e r o f Mines r e p o r t s .  t h e s i s , except  the Dart d e a l i n g w i t h the  ^tlin  R u f f n o r mine, does not r e p r e s e n t o r i g i n a l work, but i s a cornD i l a t i o n o f g e o l o g i c a l d a t a assembled d u r i n g the l a s t 20 o r years.  The  literature  g r e a t d e a l o f time and  on the s u b j e c t i s so e x t e n s i v e , t h a t a a t t e n t i o n was  r e q u i r e d to s e p a r a t e  g e o l o g i c a l l y Important f r o a the i n s i g n i f i c a n t and The  c o n c l u s i o n s are summarised and  the P a r t I o f the t h e s i s . r a i s e d i n the a u t h o r ' s  They r e p r e s e n t  are by no means of e q u a l v a l u e .  t h e i r own and  the  unoroven.  b r i e f l y state.* i n thoughts w h i c h were  mind w h i l e r e a d i n g and  observed i n d i f f e r e n t n a r t s o f the a r e a .  are j u s t s p e c u l a t i o n s .  comparing f a c t s  These c o n c l u s i o n s  Some are o b v i o u s l y t r u e , some  They were nut down not  so much f o r  v a l u e , but r a t h e r as notes f o r f u r t h e r r e f e r e n c e  study. Not  30  enough i s y e t known o f the composite nature  and  h i s t o r y o f the g r e a t Coast Range B a t h o l i t h , v e r y l i t t l e i s  5. known o f the c o u n t r y  to the east o f I t .  U n t i l aore i s known,  a l l g e n e r a l i z a t i o n s a r e aangerous, b u t as Dr. S c h o f i e l d s a i d : " I f v / e l l d i r e c t e d p r o g r e s s i s t o be made i n t h e f u t u r e , gene r a l i z a t i o n s are necessary." I w i s h t o thank a l l t h o s e who helpeu me w i t h t h e work o f w r i t i n g t h i s t h e s i s , p a r t i c u l a r l y D r . S. J . S c h o f i e l d whose d e t a i l e d and e x t e n s i v e knowledge o f t h e s u b j e c t made h i s a d v i c e e x c e p t i o n a l l y v a l u a b l e ; I a l s o w i s h t o thank L!r. C. L. Hershiaan, manager o f t h e E n g i n e e r and At 11 n R u f f n e r  Mines,  whose i n t e r e s t and knowleage o f geology made I t p o s s i b l e f o r me t o s t u d y t h e geology i n t h e v i c i n i t y o f the mines i n f a r g r e a t e r d e t a i l t h a n would o r d i n a r i l y been p o s s i b l e f o r a mine geologist. The was  g e n e r a l g e o l o g i c a l man, i n c l u d e d w i t h the t h e s i s ,  coonile-«. on t h e b a s i s o f r e p o r t s o f t h e G e o l o g i c a l Survey  o f Canada, i s s u e d d u r i n g t h e l a s t 10 y e a r s , and BO the l a t e s t and most a c c u r a t e  knowledge o f the a r e a .  represents I believe  t h i s i s the f i r s t map, on w h i c h t h e e a s t e r n c o n t a c t o f the E a t h o l i t h , was p l o t tea. a l o n g observations.  i t s e n t i r e l e n g t h , from f i e l d  PART I .  Introduction Summary.  and  6 A l o n g t h e e n t i r e w e s t e r n c o a s t o f the American  conti-  nent extends a l o n g and rugged system o f mountain c h a i n s and r a n g e s — t h e C o r d i l l e r a o f Worth ana South A m e r i c a . The westernmost ranges i n B r i t i s h C o l u m b i a , b e l o n g i n g to the C o r d i l l e r a , a r e the Coast Range and the I s l a n d Ranges. f h e Coast Range i s taade o f g r a n i t i c i n t r u s i v e r o c k s and i s f l a n k e d by o l d e r s e d i m e n t a r y and v o l e a n i e r o c k s , f o l d e d and metamosnhosed by c r u s t a l moveaents and h e a t o f  intrusion.  A l o n g t h e margins o f t h i s g r a n i t i c body, c a l l e d the C o a s t Range B a t h o l i t h ,  a r e found numerous o r e - d e p o s i t s .  b e l i e v e d t h a t t h e s e o r e - d e p o s i t s were formed by  It is  emanations  a r i s i n g f r o m the i n t r u d e d g r a n i t i c magma. I t i s the o b j e c t o f t h i s paper to summarize what i s known about the g e o l o g y o f the o r e d e p o s i t s a l o n g the e a s t e r n c o n t a c t o f the B a t h o l i t h ,  n o t so much I n the d e s i r e t o b r i n g  out o r i g i n a l h y p o t h e s i s on t h e i r o r i g i n , but r a t h e r t o b r i n g t o g e t h e r g e o l o g i c a l i n f o r m a t i o n s c a t t e r e d i n the c o p i o u s l i t e r a t u r e on the s u b j e c t . I n o r d e r t o do t h i s i n t e l l i g e n t l y i t i s n e c e s s a r y to get  a c q u a i n t e d n o t o n l y w i t h the g e o l o g y of the s e p a r a t e o r e -  de-DOsits, but a l s o w i t h t h e g e n e r a l g e o l o g y and p h y s i o g r a p h y of  the d i s t r i c t , and the v a r i o u s h y p o t h e s i s brought f o r w a r d  to e x p l a i n the o b s e r v e d f a c t s .  7 P h y s i o g r a p h y and Topography. {Summary) The Coast Range extends a l o n g the w e s t e r n coast o f B r i t i s h C o l u m b i a ; i n the s o u t h  i t i s separatea  from t h e Cas-  cade Range by the v a l l e y o f P r a s e r R i v e r , and i n the n o r t h connects w i t h t h e mountain systems o f A l a s k a . To t h e e a s t o f t h e Coast Rang© l i e s eau, made m o s t l y Range i t s e l f  the I n t e r i o r  o f s e d i m e n t a r y and v o l c a n i c r o c k s .  Plat-  The Coast  i s made almost e n t i r e l y o f g r a n o - a i o r i t e o f Upper  ' J u r a s s i c age. , The Coast Range and the I n t e r i o r p l a t e a u a r e the two main p h y s i o g r a p h i c  p r o v i n c e s o f the a r e a u n d e r c o n s i d e r a t i o n .  The Coast Range i s r u g g e d , w i t h b o l d o u t l i n e s and irregular erosion features.  I t i s a l s o o f a g r e a t e r average  h e i g h t than t h e P l a t e a u t o t h e e a s t , The p l a t e a u , as i t s name i m p l i e s , i s a more o r l e s s f l a t s u r f a c e , w i t h deep v a l l e y s c u t i n i t , w i t h s o f t rounded o u t l i n e s , and i s c o n s i d e r a b l y lower i n e l e v a t i o n t h a t t h e C o a s t Range, There i s no sudden break between t h e P l a t e a u ana t h e Coast Range, as the P l a t e a u g r a d u a l l y r i s e s t o the average l e v e l o f t h e Range.  The g e n e r a l u n i f o r m i t y o f e l e v a t i o n , and  the f a c t t h a t streams c u t t h r o u g h the Coast Range suggest the i d e a t h a t t h e Coast Range and the P l a t e a u behind were penep l a n a t e d and t h e n g r a d u a l l y u p l i f t e a • G l a e l a t i o n has p l a y e d a n i m p o r t a n t  r o l e i n the s c u l p -  t u r i n g o f t h e p r e s e n t t o p o g r a p h y , and even now g l a c i e r s a r e s t i l l found i n t h e Coast Range.  8. General The  Geology.  r o c k s o f t h e E a s t e r n s i d e o f t h e Coast Range may  be s u b d i v i d e d i n t o t h r e e main d i v i s i o n s .  These d i v i s i o n s a r e ;  (1) P r e - b a t h o l i t h i c r o c k s . (2) The Coast Range I n t r u s i v o a and s a t e l l i t e s . (3) The p o s t - b a t h o l i t h i e r o c k s . The P r e - b a t h o l i t h i c rooks form the g r e a t b u l k o f f o r m a t i o n s t o the e a s t of the g r e a t Coast Range B a t h o l i t h . are both sedimentary  They  and v o l c a n i c r o c k s , and range I n age f r o m  "Pre-Cambrian to'Lower C r e t a c e o u s .  As t h e B a t h o l i t h was n o t  i n t r u d e d i n t h e same t i m e t h r o u g h o u t  i t s l e n g t h i t l a Impos-  s i b l e t o s a y d e f i n i t e l y where the b o r d e r between p r e - b a t h o l i t h i c and p o s t - b a t h o l l t h i c r o c k s s h o u l d be drawn. a r e a s the Lower Cretaceous  i s definitely  I n some  post-batholithic,  w h i l e i n o t h e r s , t h e i n t r u s I v e s cut the lower members o f the Lower C r e t a c e o u s ,  and so make i t p r e - b a t h o l i t h i c .  The o l d e r  r o c k s , the Pre-Cambrian and the P a l a e o z o i c s a r e found  i n the  n o r t h ; the P r e - C a m b r i a n i n the Yukon and A t l i n D i s t r i c t s , and the P a l a e o z o i c s go as f a r s o u t h as S t i k i n e and l a k u t R i v e r s . They appear a g a i n i n t h e s o u t h as the Cache Creek and B r i d g e River series.  From S t e w a r t  t o B r i d g e R i v e r A r e a i n the s o u t h -  e r n B r i t i s h Columbia t h e r o c k s a r e p r e v a i l i n g l y M e s o z o l c . T r l a s s i o i s represented  The  i n t h e S t i k i n e and l a k u t R i v e r s a r e a s  i n t h e n o r t h , and i n the B r i d g e R i v e r and Gun Creek a r e a s i n the  south. The  J u r a s s i c i s w e l l r e p r e s e n t e d t h r o u g h o u t , and t h e r e -  f o r e r e p r e s e n t s an i m n o r t a n t p e r i o d o f s e d i m e n t a t i o n .  The main g e o l o g i c a l feature of the d i s t r i c t under cons i d e r a t i o n i s the Coast Range B a t h o l i t h . The B a t h o l i t h represents a large somewhat curved mass of g r a n o - d i o r i t l c rocks extending from the Fraser River In the south w e l l i n t o Yukon t e r r i t o r y , a distance of about 1000 m i l e s . from 60 to 100 miles wide.  Apparently  s i n g l e period of i n t r u s i o n , but was  I t i s anywhere  i t does not represent  a  intruded during s e v e r a l  periods; i t also v a r i e s l i t h o l o g i c a l l y from point to p o i n t , and therefore i s composite both i n age and i n composition. The greater part of i t , however, was  intruded during the Upper  J u r a s s i c time and t h i s period t h e r e f o r e i s considered to be the period of i n t r u s i o n . probably occurred  The e a r l i e s t i n t r u s i o n , however,  i n Lower J u r a s s i c or even T r i a s s i c age,  and  the separate i n t r u s i o n s o f parts o f the main B a t h o l i t h , and s m a l l e r s a t e l l i t i c B a t h o l i t h s continued  Into Cretaceous and  possibly l a t e r . The B a t h o l i t h l a made c h i e f l y of l i g h t gray, granod i o r i t e ; but a l l gradations from galbro to true g r a n i t e e x i s t . I t i s p o s s i b l e t h a t , as the changes from one rock to the other are abrupt, the d i f f e r e n t m a t e r i a l represents d i f f e r e n t times of i n t r u s i o n . The eastern and western contacts d i f f e r m a t e r i a l l y from each other, the main d i f f e r e n c e being the degree of ruetamorDhism, and width o f metamorphic zone; that on the  eastern  contact being quit© narrow and l e s s a f f e c t e d than the one the western s i d e .  on  This d i f f e r e n c e had very pronounced e f f e c t  on ore d e p o s i t i o n , and i s treated i n considerable  detail  10. f a r t h e r down. The p o s t - b a t h o l i t h i o r o o k s have no importance from the v i e w p o i n t o f economic geology s i n c e the g r e a t deposits But  majority  of ore  a r e connected w i t h t h e i n t r u s i o n o f the B a t h o l i t h .  t o make t h e d e s c r i p t i o n complete i t may be s a i d t h a t the  Upper C r e t a c e o u s i e r e p r e s e n t e d a t s e v e r a l p o i n t s , and t h a t the T e r t i a r y i s r e p r e s e n t e d m a i n l y by v o l c a n i c f l o w s ,  scat-  tered i n the I n t e r i o r P l a t e a u r e g i o n .  deposits  The q u a t e r n a r y  c o n s i s t m o s t l y o f g l a c i a l t i l l s , c l a y s and g r a v e l s , and some dyke r o c k s and l a v a s .  11.  Economic G e o l o g y . Summary. f h e ore d e p o s i t s a l o n g t h e e a s t e r n s i d e of the Coast Range B a t h o l i t h are i n v a r i a b l y g e n e t i c a l l y connected w i t h the Coast Range I n t r u s l v e s o r the s m a l l e r b a t h o l i t h s i n the ior plateau.  inter-  I t i s q u i t e p o s s i b l e t h a t these s m a l l e r b a t h o -  l i t h s are d i r e c t l y c o n n e c t e d w i t h t h e main b a t h o l i t h , but i s no e v i d e n c e f o r . t h i s e x c e p t the l i t h o l o g i c a l i s i s s t a t e d , i n the c h a p t e r  there  similarity,  on the C o a s t Range B a t h o l i t h , the  age o f t h i s i n t r u s i o n i s p l a c e d i n the tipper J u r a s s i c Time, although truded  c e r t a i n p a r t s o f the B a t h o l i t h seem t o have been I n -  i n Lower C r e t a c e o u s and T e r t i a r y t i m e .  b a t h o l i t h s i n the i n t e r i o r a r e c o n s i d e r e d  The  satellitic  by some t o be contem-  poraneous w i t h t h e C o a s t Range B a t h o l i t h , w h i l e o t h e r s them as l a t e as the L a r a m i d e r e v o l u t i o n . P r o b a b l y q u i t e a v a r i a t i o n i n age among them, and  place  there  Is  the B a t h o l i t h s were  i n t r u d e d a t v a r i o u s t i m e s f r o m J u r a s s i c to the Laramide  and  maybe l a t e r . It  i s therefore reasonable  to c o n s i d e r t h a t the ages  of d i f f e r e n t ore d e p o s i t s a l s o d i f f e r , w i t h i n these l i m i t s . may  be w e l l a t t h i s p o i n t to c o n s i d e r the i n t e r e s t i n g  ity  t h a t the type o f o r e d e p o s i t , i . e . i t s m i n e r a l c o n t e n t ,  be i n f l u e n c e d by i t s age, or r a t h e r by t h e age  possibilmay  o f the p a r e n t i n -  t r u s i v e mass. There are i n d i c a t i o n s t h a t t h i s /nay be  the  P r . S. J . S c h o f i e l d has a p p l i e d the z o n a l t h e o r y f o r m a t i o n of ore d e p o s i t s , and has  It  shown t h a t the  case. of  prevailing  m i n e r a l s on the e a s t e r n f l a n k of the Coast Range B a t h o l i t h are  12.  g o l d , s i l v e r , l e a d and z i n c ; and on the w e s t e r n This g e n e r a l i z a t i o n i s very valuable  flank—copper.  because i t e x p l a i n s i n a  broad way the g e n e r a l c o n d i t i o n s o f o r e d e p o s i t i o n . p a r t i c u l a r place the general tions.  These l o c a l c o n d i t i o n s  B u t a t any  l a w may be o f f s e t by l o c a l are;  (a) The c o m p o s i t i o n o f g r a n i t i c magma i n t h i s (b) The c h a r a c t e r (c) D i s t a n c e  condi-  o f country  locality.  rock.  o f the d e p o s i t f r o m t h e c o n t a c t .  I t i s a w e l l e s t a b l i s h e d f a c t , t h a t the c o m p o s i t i o n o f the g r a n i t i c magma v a r i e s c o n s i d e r a b l y the C o a s t Range B a t h o l i t h .  from p l a c e  to p l a c e i n  I t i s also well established  that  the B a t h o l i t h i s c o m p o s i t e , and t h a t d i f f e r e n t p o r t i o n s o f i t may  be o f d i f f e r e n t age.  D r . S c h o f i e l d has d i s t i n g u i s h e d  p h a s e s , t h e B r i t a n n i a , t h e C o l u m b i a , and t h e C a l e d o n i a and  three  phase,  t h e r e may be more. I t l a q u i t e p o s s i b l e t h a t these d i f f e r -  ent phases were c h a r a c t e r i s e d by d i f f e r e n t m e t a l l i c m i n e r a l s . I n t h e W h i t e h o r s e d i s t r i c t , D. D. C a i r n e s  said  the C o n t a c t Metamorphic Copper d e p o s i t s a r e d e f i n i t e l y than the s i l v e r — l e a d — g o l d d e p o s i t s .  that older  I t i s n o t p o s s i b l e t h a t ,-;  copper was b r o u g h t by t h e e a r l i e r phases o f the i n t r u s i o n , which d i d not reach the present surface, thus producing mesothermal and e p l t h e r m a l  vein deposits?  only  I n some c a s e s i t i s  d e f i n i t e l y shown, t h a t t h e o l d e r g r a n i t e had t o be f r a c t u r e d before  t h i s second s t a g e  occurred.  I f i n a c e r t a i n l o c a l i t y the i n t r u s i o n s are of a l a t t e r phase t h a n t h e f i r s t , copper phase, t h e s i l v e r — g o l d — l e a d mine r a l s would p r e d o m i n a t e .  13. The  second, p o i n t , t h e c h a r a c t e r o f t h e c o u n t r y  rock,  does not seen t o i n f l u e n c e the d e p o s i t s v e r y much, as the same g e n e r a l type of d e p o s i t s occur i n d i f f e r e n t The  formations*  t h i r d p o i n t , — . d i s t a n c e from the contact i s very  Important, b u t i t i s p a r t l y i n c l u d e d i n the f i r s t  part—the  age o f i n t r u s i v e ; however, b e s i d e s t h a t , i t s e f f e c t i s v e r y s i m p l e , and r e s u l t s o n l y i n a l o c a l d i s t o r t i o n o f the main z o n a l arrangement.  Thus copper d e p o s i t s extend  i n a narrow  b e l t a l m o s t a l l way  a l o n g the e a s t e r n c o n t a c t o f t h e B a t h o l i t h ,  a l t h o u g h a c c o r d i n g to the g e n e r a l z o n a l arrangement t h i s s h o u l d have been a g o l d — s i l v e r — l e a d  side.  But a l l t h i s , as I s a i d b e f o r e , has e f f e c t o n l y  local-  l y , w h i l e the z o n a l arrangement d e a l s w i t h the B a t h o l i t h as a whole.  And  i f we  consider the producing mines, i t w i l l  be  c l e a r l y s e e n t h a t the mines on the w e s t e r n f l a n k a r e copper p r o d u c e r s , w h i l e t h e ones i n the e a s t a r e p r o d u c e r s s i l v e r , l e a d and  of g o l d ,  zinc.  Another v a r i a t i o n i n m i n e r a l i z a t i o n i s i n d i c a t e d i n north-south d i r e c t i o n .  Thus the d e p o s i t s i n the n o r t h a r e  p r e v a i l i n g l y s i l v e r - l e a d or antimony-gold s o u t h t h e g o l d q u a r t z v e i n s predominate i n To sum  t y p e , w h i l e to the importance.  up the p e c u l i a r i t i e s o f the economic  geology  o f the e a s t e r n s i d e o f the B a t h o l i t h i t i s b e s t to t a b u l a t e the d i f f e r e n t  facts.  14. Conclusions. By studying the ore deposits on the eastern side of the Coast Range B a t h o l i t h th© f o l l o w i n g p o i n t s were noted. (!)  The ore d e p o s i t s are g e n e t i c a l l y connected w i t h the Coast  Range I n t r u s i v e s which apparently range from Upper J u r a s s i c to T e r t i a r y i n age.  Ho ore d e p o s i t s a r e found i n the i n t e r i o r  r e g i o n , f a r away from the i n t r u s i v e s . (2)  The presence of m i n e r a l i z i n g body, l i k e the B a t h o l i t h , i s  not s u f f i c i e n t i n i t s e l f to produce commercial ore d e p o s i t s . I t i s necessary  i n c o n j u n c t i o n w i t h i t to have s t r u c t u r a l con-  d i t i o n s which would tend to concentrate the a v a i l a b l e minerals at a point. I n connection w i t h t h i s shear zones and appear to be e s p e c i a l l y (3)  fissures  important.  Ro commercial d e p o s i t s have been found c l o s e to the  contact w i t h the Coast Range B a t h o l i t h . (4)  S a t e l l i t i c b a t h o l i t h s are important, s e v e r a l deposits are  found r i g h t i n the b a t h o l i t h s , and other d e p o s i t s o f t e n d i f f e r ing from the c o n v e n t i o n a l types are found near the s a t e l l i t e s . (5)  Deposits may be found i n d i f f e r e n t formations, but c e r t a i n  g r a d a t i o n of  favourabllity  rt  n  may  be observed.  S c h o f i e l d grades  the rocks as f o l l o w s ; 1. limestones, 2. g r a n i t i c rocks, 3. d i o r i t e - g a b b r o f a m i l y , 4. v o l c a n i c t u f f , 5. q u a r t z i t e s , 6. s l a t e s . The age o f the formation, provided i t i s p r e - b a t h o l i -  15. t h i c , does not seem t o play any p a r t . (6)  The ore d e p o s i t s o f the Eastern contact may he d i v i d e d  i n t o two main groups, (1) High temperature d e p o s i t s , mostly contact metamorphic copper d e p o s i t s , (2) Intermediate and Low temperature d e p o s i t s , forming v e i n s , w i t h galena, l e a d , z i n c , g o l d , s i l v e r , a t i b n i t e and i r o n as important m e t a l l i c elements. There are i n d i c a t i o n s that these two groups belong t o two periods o f m i n e r a l i z a t i o n , one immediately  f o l l o w i n g the i n t r u s -  i o n , — p r o d u c i n g the copper d e p o s i t s ; and the other some tima l a t e r , may be connected w i t h the next movement of the magma, which d i d not reach the present s u r f a c e , and so produced onlyd e p o s i t s o f intermediate o r low temperature.  The second stage  might have occurred only a f t e r the core of the already c o n s o l i dated magma was f r a c t u r e d by l a t t e r movements.  P. D. Cairnes  says: "From the evidence so f a r accumulated the age of the v e i n d e p o s i t s cannot be d e f i n i t e l y determined.  That they are  of considerably l a t e r age than the contact metamorphic deposits seems t o be i n l i t t l e doubt.  They are l a t e r than the period  of c o n s o l i d a t i o n of a t l e a s t a part of the g r a n i t i c magma." In Taku d i s t r i c t Dr. Handy considers that two periods of minera l i z a t i o n are i n d i c a t e d . I t i s a l s o i n d i r e c t l y supported by the f o l l o w i n g words o f Dr. S c h o f i e l d ; "The c l o s i n g stages of the Coast Range Igneous a c t i v i t y has been most important i n the formation of mineral deposits i n B. C."' (7)  The copper d e p o s i t s o f the eastern contact are confined  to a narrow b e l t near the c o n t a c t , mostly i n limestones and i n  16. the g r a n i t e i t s e l f .  They occur a l l along the contact from  Whitehorse, through A t l i n , Gun Creek, and Bridge R i v e r Areas to Coguihalla Area, mostly as c o n t a c t metamorphic, but sometimes as v e i n d e p o s i t s .  Hone of them have been worked with  any success. (8)  I t seems t h a t gold i s more important m i n e r a l i n the south-  ern p a r t of the area under c o n s i d e r a t i o n , and that s i l v e r - l e a d i s more abundant to the north.  This a g a i n brings out the pos-  s i b i l i t y that intrusions o f various age are l i k e l y to bring d i f f e r e n t minerals; and that difference in mineralization i s brought about not only by zonal arrangement cut by differences in' the parent magma i t s e l f . (9)  Secondary enrichment played an important r o l e in formation  of workable ore (10)  deposits.  From the commercial standpoint the Eastern side of the  B a t h o l i t h i s e s s e n t i a l l y a belt o f gold, s i l v e r , lead and zinc minerals.  The occurrence  of copper i s i n t e r e s t i n g only geolo-  gically. (11)  A l l important  ore deposits of the eastern flanks are  true vein type occurring e i t h e r i n f i s s u r e s or shear zones. (IS)  In several cases the mineralized f i s s u r e s have a very  constant s t r i k e and'dip, which i n connection with t h e i r great l e n g t h , i n d i c a t e s that these f i s s u r e s were formed by compreesional stresses. pressure was  The 1.1. o r N.W.  coming from the west.  s t r i k e suggest that the  17. (13)  Dr. S. J . Schof i e l d s a y s r  "The f i s s u r e s s t r i k i n g n o r t h -  w e s t e r l y are g e n e r a l l y c h a r a c t e r i z e d by the presence o f copper m i n e r a l s , while those s t r i k i n g n o r t h - e a s t e r l y are known f o r t h e i r g o l d , or s i l v e r - l e a d  content."  S. J . S c h o f i e l d , " F i s s u r e s Systems i n B. C. I n s t . Mining & Met.  July,  1925.  n  B u l l . Can  18.  PART I I .  Or© Deposits o f the 'Eastern of the  Coast Hange B a t h o l i t h .  sm®  19  General Topography a M Physiography. B r i t i s h Columbia l i e s i n the C o r d i l l e r a n b e l t of K o r t h America.  The Canadian C o r d i l l e r a are p a r t of a great mountain  system which extends along the P a c i f i c Coast and i s continuous from the northern p a r t of R o r t h America to Cape Horn o f South America. The Ganadian C o r d i l l e r a are c l a s s i f i e d as f o l l o w s ;  Homenolatxire o f Mountains I n Western Canada, 1918. Western B e l t . (a} P a c i f i c System  (Cascade Range [Coast Range.  (b) I n s u l a r Systes  (Vancouver I s l a n d Range (Queen C h a r l o t t e I s l a n d Range 1st. S l i a s Range. Central Belt.  (a) Columbia System  ] S e l k i r k Range [Cariboo Range  (Gold Ranges)  (b) I n t e r i o r System  (Monashee Range (Fraser P l a t e a u ( (Nechako P l a t e a u  (c) Caasiar System (d) Yukon System  Babine Range Istickeen Range. (Yukon P l a t e a u .  30.  Eastern B e l t . (a) Rockies System  (Rocky I t . Range (llacKenzie Range ( F r a n k l i n Range ( F o o t h i l l s Range.  (b) A r c t i c System  (Richardson Range.  This c l a s s i f i c a t i o n can he s i m p l i f i e d considerably f o r  the purpose of t h i s paper, s i n c e o n l y the Eastern side o f the Coast Range i s c o n s i d e r e d .  ! e may t h e r e f o r e make a general r  s u b d i v i s i o n as f o l l o w s : (a) The Coast Range. lb) The I n t e r i o r P l a t e a u . The I n t e r i o r P l a t e a u w i l l include a l l the r e g i o n i m m e d i a t e l y east of the Coast Range proper, and such p l a t e a u r e g i o n s as the Yukon, fleehako and F r a s e r P l a t e a u s .  That such  general d i v i s i o n i s j u s t i f i a b l e w i l l be seen from f u r t h e r discussion.  21. The Coast Range. The Coast Range i s mad® of s e v e r a l p a r a l l e l .ranges, trending northwest and s o u t h e a s t . I n g e n e r a l th© Coaet Range i s v e r y rugged, presenting a complex of needle l i k e peaks, saw-toothed r i d g e s , and deep oanyon l i k e gorges.  I n places the o u t l i n e s ar© ©ore rounded,  or even f l a t * but as a whole the most c h a r a c t e r i s t i c feature of ..the Range. i s the i r r e g u l a r i t y and sharpness o f i t s forms. T h i s c a n be p a r t l y explained by the f a c t that the Coast Range I s made almost e n t i r e l y o f th© g r a n i t i c 'rocks o f the Coast Range- B a t h o l i t h , and as no bedding planes are present the weathering and e r o s i o n produces ©oat f a n t a s t i c forma. The e l e v a t i o n of the Coast Range v a r i e s from South to North*  I n the .south the Range i s higher, and separate peaks  reach the e l e v a t i o n o f IE,000 f e e t , while i n the north the e l e v a t i o n s are around 8,000 f e e t . S h i s change i n a l t i t u d e , though g r e a t , i s so gradual that i t does not break t h e apparent u n i f o r m i t y of summit l e v e l , whieh, however bears no r e l a t i o n  t o s t r u c t u r a l features*  This  terrane has thus been considered by a number of g e o l o g i s t s who have studied i t t o p o g r a p h i c a l l y , to represent a peneplanated, o r a t l e a s t a mature to o l d surface of e r o s i o n , subsequently elevated.  22. I n t e r i o r Plateau-System. To the e a s t o f t h e C o a s t Rang© l i e s a wide u p l a n d r e g i o n , w h i c h i n v a r i o u s p a r t s of t h e p r o v i n c e i s g i v e n d i f f e r e n t names s u c h a s F r a s e r P l a t e a u , Heehako P l a t e a u , Yukon P l a t e a u , b u t i s e s s e n t i a l l y t h e same p h y s i o g r a p h i c p r o v i n c e t h r o u g h o u t , and ©an be b e s t naaed a s t h e I n t e r i o r P l a t e a u . I t i s an u n d u l a t i n g and i n p l a c e s h i l l y r e g i o n about 3,500 to 4,000 f e e t i n e l e v a t i o n . In  p l a c e s some w e l l d e f i n e d ranges l i e w i t h i n t h i s  " r e g i o n and many, s i n g l e peaks and minor ranges r i s e above the plateau l e v e l . I n t o t h i s u p l a n d surface t h e main d r a i n a g e c o u r s e s have i n c i s e d c h a n n e l s v a r y i n g from. 3,000 to #,000 f e e t i n d e p t h , t h u s p r o d u c i n g a v e r y i r r e g u l a r ' topography.  The sum-  m i t s o f unreduced h i l l s and r . i % @ s , l y i n g between t h e w a t e r ways, mark a g e n t l y r o l l i n g pl&itt whi-eh s l o p e s toward the n o r t h and n o r t h w e s t . When viewed from one of the a d j a c e n t peaks of the Coast Range t h e s t e e p , narrow v a l l e y s a r e e n t i r e l y l o s t t o view and the  i n t e r v e n i n g a r e a s appear as a c o m p a r a t i v e l y l e v e l  plain  broken o n l y i n a few places by low, r o l l i n g h i l l s or an  occas-  i o n a l sharp v o l c a n i c cone of recent o r i g i n . In  some areas the I n t e r i o r p l a t e a u i s more than o r d i n -  ary./level owing t o the w i d e s p r e a d f l a t l y i n g T e r t i a r y l a v a flows upon which l i e s a mantle o f g l a c i a l t i l l o f s u r p r i s i n g l y uniform  thickness. C o o k f i e l d , d e s c r i b i n g the plateau between A t l i n  and  23. Telegraph. Creek says: 1 ! e l l rounded or f l a t - t o p p e d h i l l s , and w  wide, deep v a l l e y s are the c h a r a c t e r i s t i c forms.  The plateau  continues t o the northwest where I t i s known as the Yukon p l a t e a u , but t h e southern part of the a r e a i s a v a s t l a v a p l a t e a u d i s s e c t e d to some e x t e n t , age o f which r e l a t i v e to that of the p l a t e a u t o t h e north i s unknown; i t may be cons i d e r a b l y younger." Along the northern p o r t i o n of t h e Coast Range, the g e n e r a l suiamit l e v e l merges i n t o that o f the Yukon p l a t e a u , i n a maimer suggesting the' synchronous p l a n a t i o n of these two p r o v i n c e s , a view that i s held by Brooks, Spencer, Cairnes and o t h e r s ; but d u r i n g the v a r i o u s v e r t i c a l movements that have a f f e c t e d these t e r r a n e s , the u p l i f t has been g r e a t e s t • along the a x i s of the Coast Range and l e a s t along that o f the Yukon plateau p r o v i n c e , which t e r r a c e i s thus given the contour of a huge f l a r i n g trough whose median l i n e i s , i n a general way marked by the present p o s i t i o n o f the Yukon River from near i t s headwaters i n northern B r i t i s h Columbia to B e r i n g Sea.  24..  A t h i r d physiographic  feature i s recognized by some  w r i t e r s , notably V. Do Image and J . H. M a r s h a l l , to which they give the name " T r a n s i t i o n s ! Zone." Quoting M a r s h a l l , "Between the Coast Range and  the  I n t e r i o r P l a t e a u there l a a t r a n s i t i o n zone characterised by rounded, f l a t - t o p p e d mountains whose e l e v a t i o n s g r a d u a l l y change from 3,000 f e e t in the east to 6,000 and even 7,000 f e e t i n the west.  The axes of the r i d g e s in t h i s t r a n s i t i o n a l  zone a l l trend a t r i g h t angles to the. axes of the Coast Range, i . e . , northeast and southwest, and the r i d g e s appear to proj e c t fro© the Coast Range as a s e r i e s o f spurs. t h i s zone l a approximately massif separated  15 m i l e s .  The width  Each ridge i s a  of  separate  from i t s neighbours by broad, steep sided  *W-* shaped v a l l e y s , a l s o running northeast and southwest.  The  smooth, rounded o u t l i n e s and g e n t l e east slopes of these s e v e r a l blocks, together with t h e i r complete i s o l a t i o n , form one of the s t r i k i n g topographic The r i d g e s forming  f e a t u r e s of the d i s t r i c t .  t h i s t r a n s i t i o n a l zone undoubtedly  once formed p a r t o f the Coast Range and possessed features s i m i l a r ' to i t . Following the p a r t i a l r e t r e a t of the continent a l ice-sheet,' which covered even the highest peaks i n the  J . R. M a r s h a l l . ¥, Bolmage.  Sum.  Sum.  Rept. 1925.  Rept. 1924.  p.  p. 61.  144  25.  area and l e f t i n i t s wake more or l e s s smoothly rounded summ i t s , huge tongues o f ice remained on the higher summits, and i n the p r e - e x i s t i n g v a l l e y s . These coalesced to form an Ice-sheet of l e s s e r extent than that o f the c o n t i n e n t a l ice-sheet at th© time of i t s maximum development.  Well-defined g l a c i a l t e r r a c e s and smo-  o t h l y truncated slopes on almost a l l o f these r i d g e s a t approximately 2,800 f e e t above the v a l l e y bottoms are evidences of the e f f e c t i v e a c t i o n of these i c e tongues i n carving the present topography. G l a c i a t i o n has been the dominant f a c t o r i n moulding the present topography throughout the area.'  1  Another i n t e r e s t i n g f e a t u r e of t h i s zone i s , that numerous streams s t a r t i n the Coast Range proper, flow eastward through the " T r a n s i t i o n Z o n e a n d then turn a b r u p t l y and flow west c u t t i n g the Coast Range, t o the P a c i f i c Ocean. The f a c t that the main drainage channels cut through the Coast Range i s a good argument i n favour of peneplanation, and the gradual u p l i f t of the area. Th® smaller streams f l o w i n g eastward are probably more r e c e n t , and flow east becauae the Coast Range has higher e l e v a t i o n t h a t the P l a t e a u r e g i o n ; t h i s drainage was undoubtedly developed a f t e r the u p l i f t .  The theory that the main drainage  system antecedes the u p l i f t i s f u r t h e r supported by the f a c t that numerous of these east f l o w i n g secondary streams are captured by the main streams and thus made to flow westward. The higher e l e v a t i o n of the T r a n s i t i o n Zone, can  26.  p o s s i b l y be e x p l a i n e d by two f a c t o r s . ( 1 ) The r o c its have been hardened by t h e heat d u r i n g the i n t r u s i o n o f t h e B a t h o l i t h , and so w i t h s t o o d  the e r o s i o n  better, (2) She i n t r u s i o n of t h e B a t h o l i t h u p l i f t e d  the  s e d i m e n t a r y and volcanic r o c k s i n i t s immediate v i c i n i t y .  27. G e o l o g i c a l H i s t o r y off B. C. F a r t h e r down a t a b l e off f o r m a t i o n s , compiled  from  d i f f e r e n t places along the eastern contact of the B a t h o l i t h , and a b r i e f d e s c r i p t i o n o f t h e s e f o r m a t i o n s w i l l be f o u n d . From these i t may be c l e a r l y seen t h a t a f a i r l y complete geol o g i c record e x i s t s i n the P l a t e a u r e g i o n of B r i t i s h Columbia. fhe lower P a l o e o z o i c i s r a t h e r p o o r l y s u b d i v i d e d , but s t a r t i n g w i t h Devonian, every p e r i o d i s w e l l represented. I t i s n o t the o b j e c t o f t h i s t h e s i s t o go i n t o d e t a i l s of t h e g e o l o g i c a l h i s t o r y of the d i s t r i c t ,  but a brief  descri-  p t i o n o f t h e main p o i n t s I s n e c e s s a r y . I t was e a r l y r e c o g n i z e d by G. 1'. Dawson, t h a t one o f the main, problems t o be s o l v e d i n B r i t i s h C o l u m b i a , i s to e s t a b l i s h t h e s o u r c e from w h i c h t h e sediments eame.  G.Ll. Daw-  son t h e n b r o u g h t f o r w a r d h i s h y p o t h e s i s t h a t t h e Shuswap t e r ra ne r e p r e s e n t e d t h e o r i g i n a l s o u r c e  of sediments.  v i e w s , i n a g e n e r a l way, were l a t e r h e l d by D a l y .  Similar However,  t h e e x p l a n a t i o n was n o t q u i t e s a t i s f a c t o r y , because o f t h e e v i dence t h a t t h e sediments came from t h e west. Then S. J . S c h o f i e l d p r e s e n t e d h i s h y p o t h e s i s o f the C a s o a d i a Land i n the P a c i f i c , w h i c h agrees v e r y w e l l w i t h t h e field  evidence.  The G e o l o g i c a l Record o f t h e C o r d i l l e r a i n Canada, by S. J . S c h o f i e l d . T r a n s a c t i o n s o f t h e R o y a l S o c . o f Canada, v o l . X V I I . ser.  iii,  1923. P. 79.  28. "'This hypothesis supports the occurrence of a land mass, Cascadia, s i n c e B e l t i a n time i n an area now occupied by the waters of the P a c i f i c Ocean. (1} During B e l t i a n times.a narrow b a s i n of sedimentat i o n s t r e t c h e d northwestward through the eastern part of B r i t i s h Columbia to the Yukon and Alaska as defined by Daly. (2) A P a l a e o z o i c and e a r l y Hesozoio b a s i n of sediment a t i o n extended  from t h i s o l d land of Cascadia eastwards to  the Canadian S h i e l d .  The eastern shore l i n e of Cascadia dur-  ing these and l a t e r p e r i o d s , s t r e t c h e d i n a n o r t h w e s t e r l y d i r e c t i o n j u s t west of the present ooast l i n e of ITorth America. The northern border o f Cascadia extended i n a westerly d i r e c t i o n j u s t south of the p e n i n s u l a of A l a s k a . (3) During the Jurasaide r e v o l u t i o n , four great mount a i n chains appeared  i n this basin.  (a) The Vancouver Island—Queen C h a r l o t t e Island Range. The Coast Range of B r i t i s h Columbia, (a) The S i e r r a Nevada Range. (c) The S e l k i r k s and t h e i r extension northwards  and south-  w a r d a — i n t o the B i t t e r r o o t and Clearwater Ranges. (d) The A l a s k l d e s on the northern border of Cascadia. (4) The g r a n i t o B a t h o l i ths which accompanied the Juraaside r e v o l u t i o n were invaded during Upper J u r a s s i c times. rl"  (5) Basins o f Cretaceous sedimentation oocucced both f l a n k s of these J u r a s s i c  mountains.  on  (6) These baalas i n Canada a t l e a s t , were a f f e c t e d by the Laramide r e v o l u t i o n , which was accompanied a l s o by igneous intrusions. (?) Small T e r t i a r y basins of sedimentation with l o c a l outpourings o f v o l c a n i c m a t e r i a l marked the Lower T e r t i a r y which was brought to a c l o s e by l o c a l mountain b u i l d i n g and igneous i n t r u s i o n a t the end o f Oligocene. (8) Down f a u l t i n g and down f o l d i n g probably a t the c l o s e of the Miocene, have b u r i e d the ancient land mass of Cascadia beneath t h e waters of the P a c i f i c Ocean.  Yaat f l o o d s  o f l a v a were outpoured l a B r i t i s h .Columbia and Oregon. (9) The v u l c a n i a a o f l a t e T e r t i a r y , P l e i s t o c e n e , and the present p e r i o d s i s a s s o c i a t e d with the s i n k i n g o f Cascadia, which has caused and i s causing a period o f t e n s i o n along the P a c i f i c Coast.*  T h i s covers a l l t h e important phases o f the g e o l o g i c a l h i s t o r y of B r i t i s h Columbia, and no more need be s a i d about i t .  fhe Coast Range B a t h o l i t h .  fhe dominant -geologic feature of the western part of B r i t i s h Columbia i s the Coast Range B a t h o l i t h ,  For t h i s r e a -  son i t i s considered separately from the other formations. I t i s of a paramount importance i n r e l a t i o n to the ore d e p o s i t s , since the great majority of ore d e p o s i t s along i t s western and  eastern contacts are i n d i r e c t connection w i t h the i n t r u s i o n of t h i s enormous g r a n i t i c mass. 1  I t ranges from the I n t e r n a t i o n a l boundary i n the south to the Yukon d i s t r i c t In the north.  I t i s about 100 m i l e s  wide i n the south and g r a d u a l l y t a p e r s northward.  The average  width may "be taken as approximately 60 miles. In composition the B a t h o l i t h v a r i e s considerably,.  The  v a r i a t i o n i s more pronounced t r a n s v e r s e l y than longitudinaly. The core i s u s u a l l y grano-diorite, but nearer the eont a c t true d i o r i tes, quartz-dlori tes, and occur.  quartz-monzonltes  In places true granites have been reported; but in  general i t may  be sa i d , that vui s u f f i c i e n t data i s s t i l l  able i n regard to the petrology o f the B a t h o l i t h . considered by most geologists and was  intruded  It i s  availnow  that the B t t h o l i t h i s composite,  not as a whole mass, but r a t h e r  gradually;  the f i n a l result being a composite b a t h o l i t h , which may  be  regarded as several smaller i n t e r l o c k i n g b a t h o l i t h s .  I n Southeastern Alaska the composition v a r i e s from S u s r t z - d i o r i t e i n the western part of the Batholith to a quartzmonzonite on the eastern f l a n k , the core being t y p i c a l l y granodiorite.  This indicates that successive rook belts from west  31. to east c o n t a i n i n c r e a s i n g amounts o f a l k a l i f e l d s p a r s and q u a r t z , and decreasing amounts o f basic c o n s t i t u e n t s . A l s o , accompanying t h i s change, there i s a marked i n crease i n s i l i c a content as the eastern border i s approached. These changes a r e not a t a l l gradual but take place r a t h e r abruptly.  This feature would tend to suggest the existence o f  a group o f c l o s e l y i n t e r l o c k i n g B a t h o l i t h s .  # I n the A t l i n D i s t r i c t Gairnes  r e p o r t s that a t y p i c a l  specimen fro© the eastern border i s on the b o r d e r - l i n e between a g r a n o - d i o r i t e and a quartz-raonzoni t e . Dalmage concluded  i n d e s c r i b i n g about 150 miles o f the B a t h o l i t h  that there was a tendency f o r the more a c i d types to  l i e along the c e n t r a l part o f the B a t h o l i t h . Another feature e x h i b i t e d by the rocks i s that o f a gneiasold character which i s f a i r l y common.  This s t r u c t u r e , a  primary one, was probably formed before and during the process  d of c o n s o l i d a t i o n . Two iraportant f a c t o r s  which give r a i s e to  t h i s g n e i s s o i d character a r e ; (1} the p a r a l l e l o r i e n t a t i o n o f the mineral p a r t i c l e s , and (2) the r e l a t i v e segregation o f the l i g h t and dark m i n e r a l s . I n a d d i t i o n t o t h i s there are a l s o the i n j e c t i o n and r e a c t i o n gneisses. ^Oalrnes D. D.  Geol. Surv. Can. Mem. 37, p. 57 - 59.  @  7. Dalmage, Geol. Surv. Oan.  4  Buddingtoa,  A * P.  Sum. Rept. 1922, P. 16 A.  I . S. Geol. B u l l . 800, p. 238.  32.  The C o a s t Range B a t h o l i t h i s c o m p o s i t e not o n l y due i t s composition  bat a l s o due  to  to d i f f e r e n t times of i n t r u s i o n s .  F. km K e r r Says; f h e B a t h o l i t h i n the ' S t i k i n e H i r e r area i s B  c o m p o s i t e i n t h a t i t was periods r a t h e r than  d e v e l o p e d d u r i n g .several i n t r u s i v e  one."  By l o o k i n g a t t a b l e c o r e i a t i n g the d i f f e r e n t  formations  i t i s quit© c l e a r t h a t t h e B a t h o l i t h , i n i t s main p o r t i o n a t l e a s t , was  I n t r u d e d d u r i n g the Upper J u r a s s i c t i m e .  i s t h e g e n e r a l o p i n i o n o f a l l g e o l o g i s t s who eastern contact o f the B a t h o l i t h .  And  worked on  However, t h e r e a r e  this the  indicat-  i o n s t h a t some' p o r t i o n o f the B a t h o l i t h say have been i n t r u d e d # b e f o r e and  after this nain period of intrusion.  s a y s : "The  composite nature  So F. A.  Kerr  o f the B a t h o l i t h c l e a r l y i n d i c a t e s  t h a t i t s development t o o k p l a o e o v e r a l o n g p e r i o d o f  time.  G r a n i t i c masses c u t P a l a e o z o i c s e d i m e n t s and T r i a s s i c v o l c a n i c s , and  dykes t h a t may  have o r i g i n a t e d w i t h such masses  even tipper c r e t a c e o u s  sediments,  penetrate  f h e b a s a l member o f the J u r a -  s s i c a e r i e s c o n t a i n s an abundance o f g r a n i t i c b o u l d e r s , i n d i c a t i n g t h a t p a r t o f t h e B a t h o l i t h had unroofed before  that period,  although  i n t r u s i o n s o f even P a l a e o z o i c age  clearly  been developed  t n e r e nay  and  have been  i n this section, i t i s bel-  i e v e d t h a t development o f t h e Coast Range B a t h o l i t h p r o p e r began e a r l y i n t h e T r i a s s i c and c o n t i n u e d p a r t o f the K e s o z o i c a c t i v i t y may  #  era.  t h r o u g h o u t the  greater  P o s s i b l y d y i n g - p h a s e s - o f t h i s igneous  have c o n t r i b u t e d i n some s m a l l way  F. A. K e r r , G e o l . S u r v . C a n a d i a n Sum.  a t even l a t e r  Rept. 1928,  p.  28  33. periods *  l a t h e map  :  a r e a i t has been p o s s i b l e t o s e p a r a t e  B a t h o l i t h i n t o s e c t i o n s t h a t are c l e a r l y of markedly  the  different  a g e s , b a t t h e r e does not appear t o be any s y s t e m a t i c a r r a n g e ment o f these s e c t i o n s . * I t may  1  be p o i n t e d out,  however, t h a t t h e o c e o r r e n c e  g r a n i t i c b o u l d e r s and p e b b l e s i n the Lower J u r a s s i c i s not  of con-  c l u s i v e e v i d e n c e i n r e g a r d t o the time o f t h e i n t r u s i o n o f t h e B a t h o l i t h , as t h e b o u l d e r s may  have e a s i l y come from the o l d  mountains o f C a s c a d i a . I t may  be w e l l t o remember here t h a t D. D. C a i r n e s ,  p l a c e d on t h e same e v i d e n c e t h e Laberge s e r i e s , as p o s t  intrus-  i v e , w h i c h l a t e r C o o k f i e l d has d e f i n i t e l y shown t o be p r e i n v a s i v e , and o c c u p y i n g Lower J u r a a s i c . Much b e t t e r e v i d e n c e i s a v a i l a b l e , t h a t some p o r t i o n s of  the B a t h o l i t h were i n t r u d e d i n p o s t J u r a s s i c t i m e s .  # V. Dolmage  s t a t e s : "The  d e f i n i t e l y known. localities  age  o f Goast Range B a t h o l i t h i s not  The B a t h o l i t h has been found i n s e v e r a l  t o eut the K a z e l t o n f o r m a t i o n which c o n t a i n s M i d d l e  J u r a s s i c and p o s s i b l e Upper J u r a s s i c f o s s i l s , thus  indicating  the age o f the B a t h o l i t h t o be not e a r l i e r than Upper J u r a s s i c . I n the v i c i n i t y  of T a t l a y o k o Lake and I n B r i d g e R i v e r map  area,  s m a l l B a t h o l i t h s , s i m i l a r i n c o m p o s i t i o n t o the Coast Range B a t h o l i t h and s i t u a t e d o n l y a few m i l e s from i t , c u t r o c k s cont a i n i n g Lower C r e t a c e o u s  fossils.  I n Taseko Lake d i s t r i c t what  a p p e a r s t o be t h e m a i n Coast Range B a t h o l i t h c u t s a t h i c k  #  V. Dolmage, G. S. C. Sumrn. Rept. 1925,  p. 161  A.  .34. s e r i e s o f c o a r s e , •• f r a g c i e n t a l v o l a a n l c r o c k s i n which t h e w r i t e r fount. p l a n t r e m a i n s ,  determined by .Prof* Edward i l . Berry,, o f  Johns Hopkins U n i v e r s i t y , t o be o f C r e t a c e o u s  age.  l a the B e l l a o p o l a — f a t l a a r e a the main B a t h o l i t h i a t r u d e s , a t many p l a c e s , r o e k s c o n t a i n i n g f o s s i l s o f Lower Cretaceous age*  T h i s e v i d e n c e proves t h a t t h i s p a r t , a t l e a s t ,  ©f the B a t h o l i t h i s youngerr^mn the l o w e s t Cretaceous, and t h e evidence found i n T a t l a y o k o L a k e , Taseko Lake and B r i d g e  liver  d i s t r i c t s s t r o n g l y s u g g e s t s t h a t much o f t h e e a s t e r n p a r t of the B a t h o l i t h I s o f p o s t n a s a l Lower Cretaceous."  One  i n t e r e s t i n g g e n e r a l f e a t u r e w i t h the Coast Range  B a t h o l i t h , i s t h a t as we go n o r t h , the B a t h o l i t h cuts progressively o l d e r roeks* R e f e r r i n g t o t h e map,  i t . i s s e e n t h a t i n the south,  w i t h the s i n g l e e x c e p t i o n o f C o g u i h a l l a and B r i d g e R i v e r a r e a s , t h e B a t h o l i t h c a t s Me so z o i c r o c k s , from P o r t l a n d C a n a l northswards . P a l a e o z o i c s appear; and f i n a l l y i n the A t l i n d i s t r i c t  and  i n t h e Yukon, t h e B a t h o l i t h cuts • Pre-Cambrian r o c k s . • T h i s l a i m p o r t a n t both-from .physiographic and  struc-  t u r a l viewpoints.  As has been mentioned b e f o r e , the Coast Range B a t h o l i t h was g r e a t l y r e s p o n s i b l e f o r formation o f ore deposits along i t s c o n t a c t s , and a l s o f o r metamorphism o f the rocks w i t h which i t came i n c o n t a c t .  In regard to both these p o i n t s i t i s best to  quote Dr. S. J . S e h o f i e l d .  #  # S. J . S e h o f i e l d . Ore Deposits o f B r i t i s h ! Qeol. Surv. Canada, Mem* 132* p. 63.  Columbia,  35.  "There are two main mineral b e l t s In B r i t i s h Colombia separated from each other by an elongated and curved area o f g r a n i t e 3 a t h o l i t h s , belonging mainly to the e a r l y part o f Me30zoic e r a .  This mass i n c l u d e s the Coast Range B a t h o l i t h and  the majority o f the B a t h o l i t h s o c c u r r i n g i n the southern part o f B r i t i s h Colombia.  The b e l t which f o l l o w s along the P a o i f i c  Coast, i n c l u d i n g the i s l a n d fringe on the western aide o f the Coast Range B a t h o l i t h , may be c a l l e d the P a c i f i c mineral b e l t * that along the eastern s i d e of the same B a t h o l i t h , the I n t e r i o r mineral b e l t .  I t w i l l be remarked that the two b e l t s d i f f e r i n  the m i n e r a i o g i o a l composition o f t h e i r ore-bodies.  The  ore  deposits of the P a c i f i c b e l t are sought mainly f o r t h e i r copper content; those of the I n t e r i o r b e l i are sought mainly for t h e i r g o l d , s i l v e r and l e a d content......" "The reason f o r the separate occurrence o f copper on the one border and o f g o l d , s i l v e r , and lead on the other border o f the great complex o f igneous i n t r u s i o n s i s not at once apparent.  A f a c t that may throw some l i g h t on the subject, i s  that copper ore deposits are not confined t o true f i s s u r e v e i n s , but resemble impregnations o f the country rock by minerals suoh D  Mr  as p y r i t e , p y r r h o t i t e , o h a l e o p r z r i t e , which i n d i c a t e c o n d i t i o n s o f high temperature  and pressure, even bordering on those o f  contact d e p o s i t s , whereas the g o l d - s i l v e r and s i l v e r - l e a d depos i t s are u s u a l l y , though not always, a s s o c i a t e d w i t h f i s s u r e veins f i l l e d under c o n d i t i o n s o f a moderate temperature pressure, the g o l d - s i l v e r being c h a r a c t e r i z e d by the  and  presence  o f such minerals as g o l d , s i l v e r , a r g e n t i t e , p y r a r g y r i t e , e t c . , i n a quartz gangue and the s i l Y e r - l e a d by galena, z i n c blende,  36. t e t r a h e d r l t a i n a gangus o f a a l c i t e , s i d e r i t e and  sometimes  quartz......." "Hot  o n l y i s t h e r e a c o n t r a s t between the ore depos-  i t s on the two a i d e s o f t h e s e S a t h o l i t i c masses, bat a l s o a c o n t r a s t i n the degree of aetamorphism e x h i b i t e d by the  pre-  b a t h o l i t i e rocks...*..."' Dr. 3 c h o f i e l d o f f e r s the f o l l o w i n g e x p l a n a t i o n f o r the f a c t s c i t e d above: "It  i s w e l l known t h a t the r o o f o f a B a t h o l i t h i s a l -  ways i n t e n s e l y metamorphosed by t h e aa««snding hot s o l u t i o n s from the u n d e r l y i n g m o l t e n magna*  On the o t h e r hand t h e deeper  and more v e r t i c a l c o n t a c t s do not show c o n t a c t m a t a u o r p h i s o to the same degree not o n l y as r e g a r d s regards  ureal axtent.  i n t e n s i t y but a l s o as  I f the B a t h o l i t h and  the i n t r u d e d  rocks  a r e e x p o s e d i n a p l a n e normal t o the v e r t i c a l p l a n e o f the B a t h o l i t h , the p l a n e would c o n s i s t o f a c o r e o f g r a n i t e s u r rounded by a c o n t a c t zone o f a p p r o x i m a t e l y  the same w i d t h .  On the o t h e r hand, i f the B a t h o l i t h and r o c k s a r e c u t o b l i q u e l y , the r o o f r o e k a w i l l be  the i n t r u d e d preserved  h i g h e r up on the low s i d e , whereas on the h i g h s i d e the h i g h l y metamorphosed r o o f r o c k s w i l l  be e n t i r e l y removed and  t a c t w i l l be u n d u l a t i n g and f a i r l y even.  The  the con-  c o n t a c t metamor-  phi o zone w i l l be v e r y narrow on the h i g h s i d e and very wide and  I r r e g u l a r on the low s i d e .  I n a d d i t i o n the low s i d e w i l l  be marked by many r o o f pendants o f a l l s i z e s , whereas the s i d e w i l l be a l m o s t f r e e from them. two  Examination  s i d e s o f t h e Coast Range B a t h o l i t h c o r r e s p o n d  high  shows t h a t the to the above  d i s t r i b u t i o n as can be Been by the f o l l o w i n g t a b l e :  37.  Baatern  Flank.  Western F l a n k .  1. Smooth f l o w i n g c o n t a c t .  1. ¥ery I r r e g u l a r c o n t a c t  2. Few  2 . Many r o o f pendants.  r o o f pendants.  3 * ¥©ry•narrow metamorphlo sone.  3 . Wide metamorphic zone.  4. S l a t e s , s a n d s t o n e s & t u f f s ehaxacteristic.  4. S c h i s t s and g n e i s s e s characteristic.  5. Moderate temp, c o n d i t i o n s .  5. H i g h temp, c o n d i t i o n s .  6. G o l d - s i l v e r and  6 . Copper d e p o s i t s o f  7.  silver-lead  d e p o s i t s o f medium tempera-  h i g h temperature  t u r e and  pressure.  pressure.  and  Intruded rooks o f r o o f type, g n e i s s e s and  schists reach  the  saiae e l e v a t i o n as t h e u n a l t e r e d r o c k s a l o n g the s t e e p l y p i t c h i n g contact»  "These f a c t s show t h a t e r o s i o n on t h e w e s t e r n s i d e o f the Goast Hangs B a t h o l i t h has not e n t i r e l y removed the r o o f r o c k s , and  t h a t t h e c o n t a c t between the B a t h o l i t h and  rocks i s almost f l a t *  T h i s c o n c l u s i o n i s supported  by  these the  p r e s e n c e o f a l a r g e number o f r o o f pendants and the v e r y  irrig-  u l a r c o n t a c t between t h e g r a n i t e and the i n t r u d e d r o c k s . On the e a s t e r n f l a n k , however, e r o s i o n has exposed a deeper p o r t i o n o f the B a t h o l i t h , the r o o f b e i n g e n t i r e l y removed, so t h a t t h e m a r g i n o f the B a t h o l i t h p l u n g e s very s t e e p l y beneath the I n t r u d e d r o o k s .  A l s o , the c o n t a c t i s  smoothly u n d u l a t i n g and the r o o f pendants a r e  absent.  T h i s p o i n t s e i t h e r to g r e a t e r u p l i f t on the e a s t e r n  Description of Formations. Pre-G'anbrlan.  The oldest r o c k s a l o n g the eastern contact o f the Coast Range Bathollfcft are found In the . i l a h i h i k Lake, the T n i t e h o r s e d i s t r i c t and t h e A t l i n  district.  These r o c k s f a l l into two groups, the Yukon group ana M-  the Mount St even 3 group, and -.vore i d e n t i f i e d by C a i r n e a probably P r e * Cumbrian i n  as  age.  The Yukon group o f the A i s h i h i k d i s t r i c t i n c l u d e s b o t h sedimentary  and igneous types, and represent probably d i f f e r e n t  ages w i t h i n the Pre-Cambrian, but they have been so h i g h l y metamorphosed t h a t In many c a s e s i t i s d i f f i c u l t to  ascertain  the nature of the o r i g i n a l rocks and c o n s e q u e n t l y , to determine their history.  The group i s represented by m i c a s c h i s t , q u a r t z -  mica s c h i s t , c h l o r i t e s c h i s t , g r a n i t e g n e i s s , and c r y s t a l l i n e limestone.  T h i s group forms, Tor the g r e a t e r part o f the area,  the rocks i n t o which the Coast Range S a t n o l i t h was  intruded,  and, t h e r e f o r e , the degree o f n e t a a o r p h l s m i s high. The lioant Stevens group Includes a number o f aeubers widely d i f f e r e n t In appearance, composition, and p o s s i b l y i n age.  They are, however, a l l o l d and  ao e x t r e m e l y  t h e i r mode o f o r i g i n and succession are obscured.  altered  that  They c o n s i s t  o f s e r l c i t e and c h l o r i t e s c h i s t s , greenstone s c h i s t s , s e r i c i t i c q u a r t z i t e s , g n e i s s o i d q u a r t z i t e a , hornblende gneisses, and c r y s t a l l i n e limestones.  #  C a i r n e s D. D.  G. S. C. Mem.  67, p. 40 -  44  40. Ho f o s s i l s have been c o l l e c t e d froea any o f the members of the Mount Stevens group and there i s consequently  no d i r e c t  evidence as t o t h e i r age, but from the evidence afforded by l a t e r igneous rocks which cut thera, they are i n a l l p r o b a b i l i t y the o l d e s t rooks i n the d i s t r i c t .  Cairnea^ i n h i a l a t e r work  along the i n t e r n a t i o n a l boundary, north o f Yukon r i v e r , ;/as able t o demonstrate t h a t the s c h i s t o s e rocks o f t h a t region were pre-middle Cambrian and i n a l l p r o b a b i l i t y Pre-Cambrian i n age. ^0 a i m as D. D.  G. 3. C.  Mem. 67, p. 40 - 44.  Devonian. Two groups o f r o c k s , o c c u r r i n g i n the S'hitehorse and A t l l a d i s t r i c t , the gold s e r i e s and the Taku group have been p r o v i s i o n a l l y assigned t o the Devonian.  The Gold s e r i e s occurs  i n two r e l a t i v e l y s m a l l areas i n the -'/hitehorse d i s t r i c t , the •tfheaton d i s t r i c t and on a r i d g e j u s t north o f Mount Miehle. This s e r i e s , ^ i i c h i a composed p r i n c i p a l l y o f pyroxenite and p e r i d o t i t e , has a trend p a r a l l e l to that o f the B a t h o l i t h i n t n i s d i s t r i c t and i s c h a r a c t e r i s e d by reddish-brown weathering of i t s rooks whioh make i t most conspicuous.  The rocks o f t h i s  s e r i e s a l s o occur i n the A t l i n d i s t r i c t , and a d e s c r i p t i o n o f them I s given i n Part I I I , on A t l i n d i s t r i c t . ( # e Gairnes propoaed t h e name Taku f o r a s e r i e s o f c h a r t s , s l a t e s and cherty q u a r t z i t e s , which have been r e f e r r e d to the  #  Gairnes, D. D.  G. S. C.  Mem. 37, p. 52 - 55.  G w i l l i m , J . G.  G. 3. 0.  An. Rept. V o l . H I *  41.  Cache Creek group o f the 30 at h a m I n t e r i o r o f B r i t i s h Columbia. I n the '.Thltehoraa d i s t r i c t t h e s e rooks o c c u r lly  I n the v i c i n i t y o f Tagish l a k e .  principa-  The nembers o f t h e s e r i e s  grade i n t o o.no another, and, I n p l a c e s , are s u c h f o l d e d and disturbed*  file3e rocks u n d e r l i e l i m e s t o n e s which are probably C a r b o n i f e r o u s i n age, and, t h e r e f o r e , have been considered as Devonian In age.  • Another group o f r o c k s , which n i g h t be grouped as Devonian, o u t c r o p i n the S t i k i n e R i v e r area.  c o n s i d e r a b l y folded and aetataorphosed  This group i s  and c o n s i s t s o f a great  t h i c k n e s s o f s l a t e s , s c h i s t s , q u a r t e t t e s , and l i m e s t o n e s .  K e r r i n h i s d e s c r i p t i o n does not d e f i n i t e l y put i n the Devonian but merely places i t as o l d e r than P e r s i a n .  Carbonlferoua. The Carboniferous rooks o c c u r i n the northern s e c t i o n o f the area under- c o n s i d e r a t i o n i n the A i a h i h l k Lake d i s t r i c t ,  the Vftiitehorae d i s t r i c t , and I n the a t l i n D i s t r i c t .  In the  south they occur I n t h e Bridge R i v e r area and the C o g u i h a l l a area. C o c k f i e l d i n the A i s h i h i k Lake d i s t r i c t and D.D.Cairnos  i n the A t l i n D i s t r i c t and th© Lewes and Kordenskiold R i v e r s Goal D i s t r i c t found outcrops o f c r y s t a l l i n e l i neb tone which, can  p o s s i b l y be c l a s s e d as Carboniferous i n age. An Important  member o f t h e Carboniferous r o c k s has been  c a l l e d the Braeburn Limestones.  T h i s name was f i r s t a p p l i e d i n  the Braeburn-iCynocks area by D. D.Cairnes , i n mem.5 o f the O.3.C.  42.  These Hetest'onea occupy a large area i n the v i c i n i t y o f Tsfcu Am, iTInfly- HI ?©r, and Tagish Bake o f the A t l i n and Whitehoroe d i s t r i c t s . S'heee limestones are g e n e r a l l y f i n e l y textured and range In c o l o u r from /greyish blue to almost white. l!r» .Dawson c o l l e c t e d F u s i l i n a e from the limestones which extend 'along the east s i d e o f Windy Are, showing these belts a t l e a s t to be Carboniferous, so the whole s e r i e s ts. thought probably to belong t o t h i s age, although no other foss i l remains o f a d e f i n i t e character have been discovered. The Carboniferous ©embers which occur i n the southern s e c t i o n o f the area under c o n s i d e r a t i o n appear i n the Bridge E l v e r and C o g u i h a l l a a r e a s . The Bridge R i v e r s e r i e s comprises nearly s e v e n t y - f i v e percent o f the rocks o f the map area.  This s e r i e s estimated to  be about 9*500 f e e t t h i c k , i s composed mainly o f c o n t o r t e d , thin-bedded cherty q u a r t z i t e s separated by t h i n f i l m s o f a r g i l l i t e s c h i s t , dark, coloured a l t e r e d a g r l l l i t e s , c r y s t a l l i n e lineotone l e n s e s , and arenaceous s c h i s t s ; flows o f black and green metabasalt.  In the v i c i n i t y o f the i n t r u s i v e rooks, the  rooks have been metamorphosed to quartz m|oa s c h i s t , squeezed conglomerate and sandstone, p n y l l i t e , t a l c o s e , s e r i c i t i c and chlorite schists. The C o g u i h a l l a i s represented i n the Carboniferous by the Cache Creek group.  This group.is represented by three d i s -  t i n c t rock types which d i f f e r g r e a t l y i n t h e i r mode o f o r i g i n . These types are v o l c a n i c greenstones, c h e r t s , and f i n e g r a i n e d , a r g i l l a c e o u s and calcareous sediments.  The greenstones are  43. composed,for the most p a r t , o f a n d e s i t i o l a v a flows which cont a i n some p y r o c l a s t i e d e p o s i t s .  The c h e r t s and s e d i m e n t s are  g e n e r a l l y so i n t i m a t e l y Interbedded i s not f e a s a b l e .  that a d e f i n i t e d i v i s i o n  The t h i c k n e s s o f these rocks by G. E. C a i r n e s ,  i s about 16,000 f e e t , 11,000 o f which i s composed o f greenstones, and the remainder o f c h e r t s and other s e d i m e n t a r y r o c k s . A considerable p o r t i o n o f the area o c c u p i e d by these rocks been p a r t l y concealed  has  by younger r o c k s .  #  C a i r n e s , C. E.  Mem.  139.  Permian. K e r r , i n summary r e p o r t s f o r 1928 and 19H9,  describes  l i m e s t o n e s I n the S t i k i n e and Iskut R i v e r s a r e a s , w h i c h he p l a c e s i n the Permian.  These a r e t h e only Permian r o c k s o c c u r -  r i n g a l o n g t h e e a s t e r n c o n t a c t of the Coast R a n g e . B a t h o l i t h . ?rlassie. The T r l a s s l o l a r e p r e s e n t e d i n the S t i k i n e and R i v e r s a r e a , i n the C h i l k o Lake and the B r i d g e R i v e r  Iskut  districts  by the O a d w a l l a d e r s e r i e s and i n the C o q u i h a l l a a r e a by the Tulaaieen group. The r o c k s i n the S t i k i n e and I s k u t R i v e r s area, a c c o r d ing  to K e r r , are a r g t l l i t e a , s l a t e s , l i m e s t o n e s , c o a r s e b r e c c i a s  and c o n g l o m e r a t e s , and v o l c a u i e a .  T h i s a c r i e j i3 c a t by the  Coast Range B a t h o l i t h . The Oadwallader a e r i e s o c c u r s as a narrow b e l t a l o n g the  w e s t e r n p a r t o f the B r i d g e R i v e r nap a r e a .  44.  I t has a t o t a l t h i c k n e s s o f 2,100  f e e t , and  i s com-  p r i s e d o f great thickness o f b a s a l t i c and a n d e s i t i c greenstone, conglomerate, sandstone and  shales w i t h s u b o r d i n a t e thin-bedded  limestones and dolomite.  A s e r i e s o f rocks  ko Lake d i s t r i c t are'very  s i m i l a r to the Cadwallader  and  o c c u r i n the  Chll-  series  can be c o r r e l a t e d to them. The Tulameen group o f the Coquihalla  area comprise a  l a r g e part of the nap area I n the southeastern s e c t i o n and a small o o r t i o n i n the extreme northern end. are composed o f sediments and  volcanic rocks.  Primarily The  also  they  former are  p r i n c i p a l l y gray or b l a c k s l a t e s , which i n c l u d e a few t h i n l i m y beds,  fhe v o l c a n i c r o c k s form the  commonly dark g r e e n , and  varieties.  The  are  i n c l u d e a c h i s t o s e , as w e l l as massive  .Alteration has progressed f a r i n a l l the a c n i s t o s e  V o l c a n i c r o c k s , and,  types.  b u l k of the group and  to a l e s s e x t e n t , i n the more massive  secondary minerals c o n s i s t of c h l o r i t e , and e d i d o t e , p  z o l s l t e , green araphibole, c a l o i t e .  One  of the members o f  tnis  s e r i e s i s a crushed g r a n i t e porphyry o c c u r r i n g as b e l t s o f s i l l s up to & s e v e r a l yards i n w i d t h .  # ¥. BoImage, C h l l k o Lake and V i c i n i t y .  Sum.  Rept.  1924.  Jurassic. ' J u r a s s i c was  bia.  a very Important period i n B r i t i s h Colum-  Great t h i c k n e s s e s of sedimentary rocks v,-ere deposited i n  a l a r g e b a s i n o f sedimentation, t h a t once occupied B r i t i s h Columbia and  as t-oosejaw.  A l b e r t a aud  the whole o f  extended at l e a s t as f a r east  I  45. f o l c a n i s m was a l s o a c t i v e ; b a t the most i m p o r t a n t event from t h e v i e w p o i n t o f economic geology was g r e a t Coast Range B a t h o l i t h . Importance  the i n t r u s i o n o f the  As t h i s event was o f paramount  t o f o r m a t i o n o f ore d e p o s i t s i n B r i t i s h Columbia i t  i s d e s c r i b e d under a s e p a r a t e h e a d i n g . I n A l a h l h i k Lake d i s t r i c t the J u r a s s i c i s p r o b a b l y r e p r e s e n t e d by a group o f r o c k s known as the o l d e r v o l c a n i c s w h i c h c o n s i s t o f green t o r e d a a d e s i t i c r o c k s w i t h a s s o c i a t e d t u f f s and b r e c c i a s .  T h e i r age  i s r a t h e r i n d e f i n i t e but they  a r e found t o be younger than t h e Yukon group o f v/hltehorse d i s t r i c t and, as they are ©at by t h e g r a n i t i c i n t r u s i v e s where v e r the two come i n c o n t a c t t h e y a r e p r o b a b l y e a r l y J u r a s s i c i n age and nay even be o l d e r . P o r t i o n s o f the o l d e r v o l c a n i c s are d e f i n i t e l y i v e i n t o t h e Laberge younger.  beds, and nay  intrus-  t h e r e f o r e be c o n s i d e r e d  C o c k f i e i d c o n s i d e r s them t o be Lower o r M i d d l e J u r a s -  sic. The  ;7hlte horse and A t l i n d i s t r i c t s a r e r e p r e s e n t e d here  by the Laberge  s e r i e s , the T a n t a l u s c o n g l o m e r a t e s , and  the  older volcanics. The Laberge  s c r i e s I s the n o s t e x t e n s i v e g e o l o g i c a l  t e r r a n e i n Taku Area b e l t , and i t s nemberc o u t c r o p i n a g e n e r a l way  throughout  the c e n t r a l , s o u t h w e s t e r n and n o r t h w e s t e r n p o r -  t i o n s o f the d i s t r i c t .  The group o f h i l l s e a s t o f Taku a r e a  and s o u t h o f Graham I n l e t ; the g r e a t e r p a r t o f the a r e a n o r t h o f P a n t a i l Lake and s o u t h o f T u t s h l Lake, on the west s i d e o f Taku a r e a ; and Sunday M o u n t a i n and the w e s t e r n p o r t i o n o f Taku mountains,  .'ire a l l l a r g e l y composed o f these r o c k s .  46. The T a n t a l u s c o n g l o m e r a t e s a r e p r o b a b l y b e s t i n c l u d e d w i t h t h e Laberge s e r i e s , because tney o v e r l i e the Laberge r o c k s conformably. I n $aeaton d i s t r i c t , where t h e most d e t a i l e d work done i n the d i s t r i c t  was u n d e r t a k e n , and where t h e b e s t exposures o f  # t y p i c a l l y marine s e d i m e n t s o c c u r , C a l r n e s  recognized a three-  f o l d d i v i s i o n o f t h e Laberge beds, a s f o l l o w s , o r i f , as i n t h e -present c a s e , t h e T a n t a l u s conglomerate be i n c l u d e d , a f o u r f o l d division:— Tantalus Conglomerate:—  T h i c k n e s s 1,800 f t .  Conglomerate, s h a l e , s a n d s t o n e , and c o a l . Laberge  Series:--  IJpper b e d s — — t h i c k n e s s 1,500 f t . 1,'lddle b e d s —  n  Lower b e d s - —  sandstone  1,700 f t . s h a l e s , s . s . , a r k o s e . 1,800 f t . arkoee and t u f f s .  total  6,000 f t .  Following c o c k f i e l d j — " F o s s i l s have been c o l l e c t e d from the Laberge beds i n 3'neatoii, 4 t l i n , './hltehorae and T a n t a l u s areas.  I n the c o l l e c -  tions- from T a n t a l u s a r e a , t h r e e forms were s p e c i f i c a l l y i d e n t i f i e d , v i s . , T r i g o n i a dawaoni, I f e r i n e a a a u d e n e a i s , and Hhfnchone l l a orfchidioides.  ?he specimens were regarded  r  by  tfhiteaves  as J u r a s s i c o r C r e t a c e o u s but two i f not a l l three of t h e s e s p e c i e s a r c now regarded as J u r a s s i c forma.  C a i r n e s D. D., Wheat on D l s t r .  O.S.O.  Mem. 3 1 , p. 54 - 56.  47, F o s s i l s c o l l e c t e d by G w i l l i t a i n A t l i n D i s t r i c t were  r e p o r t e d on by Stanton as f o l l o w s :  "these may p o s s i b l y be  T r i a s s i e , bat I t h i n k i t more p r o b a b l e t h a t they a r e e a r l y Jurassic*  They are c e r t a i n l y n o t as l a t e as the Cretaceous."#  "Thus i t a p p e a r s to be v e r y w e l l e s t a b l i s h e d  t h a t the  Laberge beds range i n age from M i d d l e Lower J u r a s s i c t o Lower Middle J u r a s s i c . "  The o l d e r v o l c a n i c s are f a i r l y abundant i n these d i s t r i c t s aloag the margin o f the Coast Range i n t r u s i v e a and a r e  s i m i l a r i n c h a r a c t e r to, those found In the A l a h l h i k D i s t r i c t . The Salmon R i v e r area i s represented i n t h i s period by throe s a i n formations.  The Bear R i v e r f o r m a t i o n , a volcanic  member which Is over £,000 feet i n t n i c k n e s s and c o n s i s t s f o r the most p a r t o f a g g l o m e r a t e s and t u f f s .  The Salmon R i v e r f o r -  mation, which i a about 300 feet t n i c k , c o n s i s t s mainly o f f i n e c o n g l o m e r a t e b e a r i n g p e b b l e s o f t h e u n d e r l y i n g v o l c a n i c neraoer  and l i e s conformably between the Bear R i v e r f o r m a t i o n and the Haas formation.  The itass f o m a t Ion c o n s i s t s mainly o f a r g i l -  l i t a s which show a d i s t i n c t s l a t y e l e a r a g e e s p e c i a l l y as t h e contact of the Coast Range B a t h o l i t h I s approached.  The  thick-  ness of t h i s f o r m a t i o n i s thought to be s l i g h t l y wore than  1,000  feet. Intruded a l o n g the bedding plane o f the t u f f s o f the  Bear R i v e r formation are s i l l s of g r a n o - d i o r i t e porphyry,  # S w i l l i m , T. C  ##  G. S. C.  Ann. Rept. . I l l , p t . 3, p. 23 - 27.  1. E. C o c k f i e i d & A . R. B e l l , G.S.C. J'em. 150, p.H£.  48. varying  I n t h i c k n e s s , b a t i n no case s o r e t h a n 500 f e e t t h i c k .  S o h o f i e l d and Hanson^, i n t h e i r r e p o r t "The  on t h e d i s t r i c t say  name P r e m i e r s i l l s i s g i v e n t o a s e r i e s o f t a b u l a r  b o d i e s t h a t were i n t r u d e d  igneous  a l o n g the b e d d i n g p l a n e s o f t h e t u f f s  o f t h e Sear R i v e r f o r m a t i o n , when t h e s e t u f f s were i n h o r i z o n tal  position.  Later  the s i l l s  and t u f f s were t i l t e d i n t o t h e i r  p r e s e n t p o s i t i o n and were s u b s e q u e n t l y exposed by e r r o s i o n . "  The a r e a between Skeena and S t e w a r t and a l s o t h e JSutsak Lake d i s t r i c t a r e r e p r e s e n t e d I n t h e J u r a s s i c by t h e K a z e l t o n group. and  The rocks: here a r e c h i e f l y t u f f s , b r e c c i a s , and f l o w s ,  have been d i v i d e d  Into  four f o r m a t i o n s :  The l o w e r v o l c a n i c d i v i s i o n c o n s i s t s o f f i n e g r a i n e d , stratified,  ivell-  r e d t u f f s 500 f e e t t h i c k l y i n g conformably below  marine s e d i m e n t s .  Below t h e s e r e d t u f f s t h e r e i s about 4,000  feet o f andesitic t u f f s , breccias  and l a v a  flows.  The_ K i d d l e s e d i m e n t a r y d i v i s i o n c o n s i s t s o f a r g i l l i t e s ,  quartz-  i t e s , and a r g i l l a c e o u s q u a r t z i t e s i n beds u s u a l l y a few f e e t thick.  T h i s d i v i s i o n i s about 500 f e e t t h i c k and abundant f o s -  s i l e v i d e n c e g a t h e r e d from i t p l a c e s i t i n the middle J u r a s s i c . The  Upper v o l c a n i c  d i v i s i o n i s c h i e f l y composed o f l a v a f l o w s  and  t h i c k massive beds o f c o a r s e b r e c c i a , a l l o f an a n d e s i t i c  n a t u r e , and v a r i e s i n - t h i c k n e s s  from 2,000 - 3 , 0 0 0 f e e t .  The Upper s e d i m e n t a r y beds, which a r e about 1 , 0 0 0 f e e t t h i c k , are composed o f a r g i l l i ' t e and l e s s e r amounts o f c u a r t z i t e , a r g i l l a c e o u s q u a r t z ! t e , and c o n g l o m e r a t e .  S c h o f i e l l 3. J . and Hanson, 0.  Mem. 1'6'd, p* 21.  49.  Setae o f the middle strate hold s e v e r a l c o a l seams. :Pre-batholitic rocks o f J u r a s s i c age a r e absent from the Chllco Lake d i s t r i c t but occur again In the Bridge River area and I n the Coguihalla d i s t r i c t . fh©  occurrence i n . the Bridge River area i s I n the form  o f a u g i t e - d i o r i f c e stock enclosed w i t h i n the C a d w a l l a d e r s e r i e s and forms the c h i e f country rock o f the gold-quartz veins i n the r e g i o n . fhe Ladner group o f rocks are the dominant rooks o f the J u r a s s i c . I n the O o j u i h a l l a area and they may be d i v i d e d i n t o two groups.  The lower group which occupies over ninety  percent  of the area covered by the a e r i e s , i s composed c h i e f l y o f s l a t y r o c k s , and I s known i n that d i s t r i c t a " s l a t e b e l t . "  The upper  group I s conformable with the rocks o f the s l a t e b e l t and i s composed o f c o n g l o m e r a t e s , tuffaeeous greywaekes, and an equal p r o p o r t i o n o f more s l a t y  rocks.  The rocks which have been under d i s c u s s i o n and which have been classed as J u r a s s i c i n age nave s t r i k i n g resemblances to the P o r p h y r i t e group o f Dawson, and as they c o n t a i n the r i c h gold a a d s i l v e r deposits o f the eastern contact b e l t , a great deal o f work has boon dene on c o r r e l a t i n g them to Dawson's f Porphyrite group  which he defined I n 1875 as f o l l o w s :  "Thin name nay be p r o v i s i o n a l l y employed t o d e s i g n a t e a s e r i e s o f r o c k s , c h i e f l y f e l d s p a t h i c and often p o r p h y r l t i c , though a l s o i n c l u d i n g d i o r i t e s o f varied t e x t u r e , the reference o f which to any o f the groups f o r m e r l y defined, seems u n c e r t a i n . Dawso.i, Q, M.  G.3.C.  Dept. of Progress 1875-76, p. £50.  50* They a r e heat seen a b o u t T a t l a y o c o L a k e , where they o v e r l i e unoomforaably the Cascade C r y s t a l l i n e r o o k s , and appear to u n d e r l i e the beds o f the J a c k a s s M o u n t a i n s e r i e s .  The  whole  o f t h e r o c k s o f t h i s group seems t o be made up o f i g n e o u s o r i g i n , though some o f them may  owe  the .arrangement o f t h e i r  m a t e r i a l to water." S c h o f i e l d and Hanson,^ i n a summary o f a number o f f a c t s conc e r n i n g t h i s c o r r e l a t i o n , b r i n g out the f o l l o w i n g {1} "The  facts.  a r e a s where the f o s s i l e v i d e n c e c o n c e r n i n g the age o f  the P o r p h y r i t e group i s most complete a r e those d e s c r i b e d by Dawson I n the v i c i n i t y o f T a t l a y o k o Lake and by M a l l o c h i n the groundhog c o a l f i e l d , and i n b o t h cases a J u r a s s i c age i s indicated.' (2) l o e v i d e n c e lav s u b m i t t e d by any o f the w o r k e r s o f a s t r u c t u r a l u n c o n f o r m i t y between t h e P o r p h y r i t e group and the o v e r l y i n g Skeena s e r i e s , w h i c h i s Koofcenay i n age, a l t h o u g h i n many p l a c e s a heavy c o n g l o m e r a t e c o n t a i n i n g p e b b l e s o f tne underl y i n g P o r p h y r i t e -group marks the, base o f the Skeena  series.  (3) The r o r p h y r i t e group i n t h e v i c i n i t y o f tne Coast Hang© B a t h o l i t h c o n t a i n s a g r e a t t h i c k n e s s o f a n d e s i t l c and aadeait© ft  b r a c c i a which i n t h e o a s t g i v e s -flay to w a t e r l a l d sediments c o n s i s t i n g o f sandstones and s h a l e s w i t h t u f f s .  The r e g i o n a l  s t r i k e o f the P o r p h y r i t e group i s no r t twve s t - s o at he --is t und i s o f C o r d l l l e r a n trend,  " h i s p o i n t e to a l i n e a r s o u r c e o f s u p p l y  f o r the P o r p h y r i t e group i n the a r e a now o c c u p i e d by the Coast Range B a t h o l i t h .  #  S a h o f i e l d , S. J . and Hanson, G., Mera. 1 3 2 , 0.3.C.  J?. 2 0 .  51.  (4) Bawsoa's conclusions of 1876  that the Porphyrite group  bridges the gap o r d i n a r i l y found between the J u r a s s i c and  the  C r e t a c e o u s i s substantiated to some extent. (5) The g r a n o - d l o r i t e o f the Coast Range proper cuts the Porp h y r i t e group, and p e b b l e s o f t h i s g r a n o - d i o r l t e are found i n  # the Lower Cretaceous of Fraser r i v e r * and i n the Laberge s e r i e s o f northern B r i t i s h Columbia and the Yukon  .  fhe presence o f these pebbles i n the Lower Cretaceous rocks supports the conclusion that the g r a n o - d i o r i t e s o f the Coast Range were intruded and s o l i d i f i e d before the Lov?er Cretaceous s t r a t a were deposited.  Shis dates the i n t r u s i o n o f  o  the Coast Eange B a t h o l i t h as p a s t - P o r p h y r i t e group and p r e Lower Cretaceous;  t h e r e f o r e . In very l a t e Upper J u r a s s i c t i m e .  Hence the P o r p h y r i t e group must be o l d e r than the Lower Cretaceous beds exposed i n F r a s e r R i v e r and the Yukon." This synopsis sums up, very c l e a r l y , the r e l a t i o n o f these sedimentary and v o l c a n i c beds w i t h the P o r p h y r i t e group and a l s o t h e i r r e l a t i o n to the Coast Range B a t h o l i t h . fhe Post B a t h o l i t h ! c rooks are o f c o m p a r a t i v e l y  little  importance to econctaic g e o l o g i s t , since tne great m a j o r i t y o f ore deposits are connected w i t h the i n t r u s i o n o f Coast Range B a t h o l i t h and i t s s a t e l l i t e s .  However, f o r the sake o f com-  p l e t e n e s s , I t was deemed advisable to neat ion t a i c - - C r e t a c e o u s and  Tertiary  the i - o a t - B a t h o l i -  deposits.  i  • 'Dawson,' S. M.,  0.3.0-  Gairnaa, D. B . ,  Sua. Hept. V o l . H I  0. i . 0»  .Meat.  31,  191L.  1896,  p.  147  -  156.  5<2» Cretaceous. Upper C r e t a c e o u s  r o c k s ooour i n t h e S t i k i n e and I s k u t  R i v e r s , a r e a , these rooks a r e m o s t l y conglomerate and sandstone w i t h a t h i n l a y e r o f v o l c a n i c s on t o p . I n t h e Salmon r i v e r a r e a , Laiiprophyro dykes a r e c o n s i d e r e d t o be l o w e r  Cretaceous  i n age. An a r e a o f p o s t - b a t h o l i t h i c C r e t a c e o u s  r o c k s l a found  near Skeeaa R i v e r , and i s known a s t h e Skeena f o r m a t i o n . formation c o n s i s t s o f a r g i l l i t e s , sandstones, glomerate  This  s h a l e s and con-  w i t h pebbles o f ^ r a n c - d l o r i t e .  In  t h e T a t l a B e l l a C o o l a and C h i l c o Lake a r e a s , the  Lower C r e t a c e o u s  s e d l a e n t s a r e c o n s i d e r e d by Dolmage to be  P r e - b a t h o l i t h i e and eons l o t o f s a n d s t o n e s , i l l i t e s and b r e c c i a .  conglomerates,  F a r t h e r south t h e Cretaceous  arg-  r o c k s are  r e p r e s e n t e d by v o l c a n i c s , m o s t l y p y r o c l a s t i e s and some a n d e s i t e tf  and b a s a l t .  These v o l c a n i c s a r e c a t by Coast Range I n t r u s i v e s ,  c o n s i s t i n g o f g r a n i t e , q u a r t z momsonite, d i o r i t e , q u a r t z diorito, etc.  The i n t r u s i v e s a r e p l a c e d as Upper  Cretaceous.^  $ lien. 130.  G. 3. C  and Sum. Rept. f o r 1928..  Tertiary. The  T e r t i a r y i n B r i t i s h Columbia was a p e r i o d o f g r e a t  volcanic a c t i v i t y .  Throughout the I n t e r i o r P l a t e a u r e g i o n a r e  e x t e n s i v e f l o w s o f these T e r t i a r y v o l c a n i c s .  The v o l c a n i c s a r e  b o t h o f t h e A c i d and B a s i c t y p e ; a c c o r d i n g to $he p r e s e n t knowledge o f the a r e a the a c i d v o l c a n i c s a r e more i m p o r t a n t i n the n o r t h ; i n the s o u t h b e g i n n i n g w i t h Sutsuk Lake and f u r t h e r t o the south the f l o w s a r o c h i e f l y  b a s a l t i c and a n l o a i t i e .  This  53. f a c t can be w e l l o b s e r v e d on t h e i n c l u d e d t a b l e o f f o r m a t i o n s .  Quaternary. The Q u a t e r n a r y w i t h t h e e x c e p t i o n o f a few dyke r o c k s , and l a v a s i s almost e n t i r e l y r e p r e s e n t e d f l u v i a l d e p o s i t s o f muds, t i l l s ,  by g l a c i a l and  and g r a v e l s .  The  deposits  are s c a t t e r e d a l l o v e r B r i t i s h C o l u m b i a , p a r t i c u l a r l y v a l l e y s and Lake  LL  flats.  In r i v e r  Soonomie geology*. I n d e s c r i b i n g the economic geology o f the eastern cont a c t o f the Coast Range B a t h o l i t h i t was considered best to s t a r t frora the n o r t h , and move southward along the contact.  The  A t l i n d i s t r i c t i s l e f t out o f t h i s d e s c r i p t i o n , as i t i s desc r i b e d i n g r e a t e r d e t a i l In the second part of t h i s paper. I t was decided not to describe separate claims and separate p r o p e r t i e s , but r a t h e r compile the geology, .and  thus  present a more g e n e r a l i z e d d e s c r i p t i o n o f the eastern contact. U n f o r t u n a t e l y , i n the a v a i l a b l e l i t e r a t u r e , the geology Is treated only l o c a l l y , very o f t e n In r e l a t i o n to a s i n g l e group of c l a i m s , and so considerable amount o f work, was n e c e s s a r y to separate the g e o l o g i c a l l y I n t e r e s t i n g and important f a c t s from such i r r e l e v a n t f a c t s as number o f c l a i m s , c a p i t a l i z a t i o n , e t c . I t was also decided to pay-more a t t e n t i o n to the producing, o r producing i n the past, o r o p e r t i e s , ' and pass over the s i a a l l prospect c l a i m s , so as not t o overload t h i s essay with apparent and not '.veil e s t a b l i s h e d f a c t s One of tne moat i n t e r e s t i n g ore deposits i n the n o r t h i s that of Keno R i l l , Mayo D i s t r i c t , Yukon. . "Mayo d i s t r i c t l i e s wi t h i n the Yukon p l a t e a u . h i l l s a r e p r e v a i l i n g l y f l a t topped and •alleys.  The  s e p a r a t e d by broad deep  <Ceno H i l l l a a t y p i c a l wedge-shaped r i d g o , l y i n g  between L i g h t n i n g , C h r i s t a l , F a i t h , and La&uc Croeka.  The  .greater p a r t o f Kayo d i s t r i c t i s u n d e r l a i n by 3 c h i s t s , which J.  Geology and Deposits, o f Xeno H i l l , Mayo D i s t r i c t , Yukon. 3. C o e k f i e l d , SUR. Rept. 19255, p.  A.  *J%/ *  a r e Intruded by s i l l s and l a c c o l i t h s o f greenstone, and by dykes and s i l l s o f g r a n i t e porphyry and quartz p o r p h y r y .  The  schist series consists of q u a r t z i t e , quartz-raica s c h i s t , g r a p h i t o s c h i s t , s e r i c i t e and c h l o r i t e s c h i s t . The greenstones i n t r u d i n g t h i s s c h i s t s e r i e s are thems e l v e s l a r g e l y sheared and a l t e r e d .  The quartz and g r a n i t e  porphyries are massive and f r e s h i n appearance and a r e believed to be offshoots from a g r a n i t e mass which outcrops some m i l e s to the e a s t , and which probably extends under a c o n s i d e r a b l e p a r t o f Mayo d i s t r i c t . The q u a r t z i t e ,  q u a r t z - m i c a s c h i s t , s;ad. g r a p h i t e  schist  are b e l i e v e d to belong t o t h e Ifacina s e r i e s , described by H e C o n n e l l i n h i s report on Klondike d i s t r i c t .  This s e r i e s has  been r e f e r r e d by Cairnes t o t h e Pre-Cambrian. The ore d e p o s i t s of -'Keno K i l l area are p r a c t i c a l l y a l l f i s s u r e veins, that i s , they represent vein material in  fault fissures.  deposited  The f a u l t s w h i c h gave r i s e to these  veins  are a l l o f normal type, and t h i s - a p p l i e s a l s o to p o a t - o i a e r a l faults. f h e v e i n s aay be d i v i d e d Into two c l a s s e s , which may be .tar.-sea l o a & i t u d i n a l and t r a as v e r s e ,  depending on whether  they follow the'trend o f the s t r a t a or out across the s t r a t a . These two f a u l t ay at eras represent  two stages of a i u e r a l i z a t i o n ,  the ' l o n g i t u d i n a l f a u l t 3 oeiag the e a r l i e r . /  •f  'j C o c k f i e i d , • J< £• S. 3. C. Sum. Hept. 1920, J ? . 3 - 4. Stockwell,' C. i l . Galena H i l l , Mayo M a t r . Suta. Rept. 1925.  56.  The  e a r l i e r m i n e r a l i z a t i o n c o n s i s t s o f quartz,  p y r l t e and p y r i t e .  After being f i l l e d ,  arseno-  the l o n g i t u d i n a l  fiss-  u r e s -remained planes o f weakness a f f e c t e d by subsequent move-  ments*  When the transverse . f i s s u r e s were m i n e r a l i z e d , they  probably acted as the main c i r c u l a t i o n channels f o r the ore bearing s o l u t i o n s and considerable were d e p o s i t e d i n them. are s l d o r i t e ,  amounts o f the ore m i n e r a l s  The c h i e f minerals o f the second stage  f r e i b s r g i t e , g a l e n a and s p h a l e r i t e .  The f o l l o w i n g m i n e r a l s rfere i d e n t i f i e d froca the Keno  Hill  deposits. E a t l v e elements-  -Silver. — A r g e n t ! t o , galena, s p h a l e r i t e ,  Sulohldes  covellite, chaloopyrite, pyrite, arsenopyrite. 3ulpho-salts  -ryrargyrite» f r e i b s r g i t e , polybaai te,  ^amesonite.  Oxides  — - i u a r t z , l i m o n i t e , manganite.  Carbonates  — SIderite, coalcite , c e r u s s i t e , raaiaofclte, a z u r i to  Sulphates  —Barite.  Genesla. By f a r t h e g r e a t e r muuber o f veins on Keno H i l l sent a s i m p l e f i l l i n g o f f a u l t f i s s u r e s .  repre-  Replacement o f w a l l  rock operated only to a a l i g h t extent, except In tne S a d i e ,freadwell vein.  The o r e m i n e r a l s i n most cases are f a s t e n e d t o  the p o l i s h e d walls o f the f a u l t f i s s u r e s , but do n o t p r o j e c t  57.  I n t o theta.  I t i s not b e l i e v e d , however, t h a t a t the time  of  m i n e r a l i z a t i o n the f a u l t s e x i s t e d as open f i s s u r e s 4 to 6, o r more, f e e t wide, but r a t h e r t h a t the small openings formed  by  the f a u l t s g r e w ' i n w i d t h as the ore~ minerals were deposited. I t has been demonstrated that t h e f o r c e exerted by a c r y s t a l i n growing l a equal to that required to crush i t #hen formed, ./hethor t h i s force was, a c t i v e , o r whether the force exerted the m i n e r a l i z i m * s o l u t i o n s was  s u f f i c i e n t t o open the  by  fissures,  i s unknown.  I n c e r t a i n cases t h e r e i s evidence o f s o l u t i o n o f w a l l rock.  This i s shown in Ho. 9 v e i n o f Keno H i l l , L i m i t e d , where  l a r g e , d r u s y c a v i t i e s l i n e d w i t h c r y s t a l s of s i d e r i t e and  gal-  ena occur i n t h e Toot w a l l . Replacement of w a l l - r o c k In the S s d i e - T r e a d w e l l v e i n , presents many characters not e x h i b i t e d In the other veins o f the a r e a .  This v e i n , o r r a t h e r "mineral zone," f o l l o w s an o l d  l i n e of weakness represented by q u a r t z - a r s o n o p y r i t e v e i n s .  I t waa probably re-opened- by a f a u l t which branches f r e q u e n t l y and  fractures.  r e - u n i t e s , w i t h c r o s s - f a u l t s between the eaain  The country  rook ir. the v i c i n i t y was  badly s h a t t e r e d  and the ,loInt Jn£ emphasized, a ad the o r e - h e a r i n g s c i at i o n s penet r a t e d each rainate creek, w i d e n i n g I t , and, the c o u n t r y rock.  In p l a c e s , r e p l a c i n g  I n places the m i n e r a l zone if. a network  tiny v e i n l e t s o f a t d e r l t e enclosing  fragments of c o u n t r y  of  rock.  Ae a r a l e t h e s e fragments l i e In t h e i r o r i g i n a l p o s i t i o n s , but i n c e r t a i n instances the p a r t i c l e s o f rock -were r o t a t e d .  These  v e i n l e t s represent on a s n a i l s c a l e what has taken p l a c e on a large scale.  Telns o f o r e p r o j e c t out Into the c o u n t r y r o c k ,  58. i n maay eases a t r i g h t a n g l e s t o t h e main trend o f the zone.  E x a m i n a t i o n o f t h i n s e c t i o n s has  grew by  shown t h a t t h e s e v e i n s  replacement o f the c o u n t r y r o c k .  Fragments o f  z i t e o r r e s i d u a l masses o f g r a n u l a t e d q u a r t z and included  in siderite.  quart-  feldspar  are  I n some c a s e s , a l s o , i n d i v i d u a l g r a i n s  o f q u a r t z are seen with  siderite projecting into  I t l a c o n s e q u e n t l y b e l i e v e d t h a t the o r e gone r e p r e s e n t s a  ore  them.  Sadie-Treadwell  f a u l t complex a l o n g w h i c h  the  deposit  grew by w i d e n i n g o f f i s s u r e s a s t h e M i n e r a l s were i e p o a i t e d , and  by  replacement.  Source o f M i n e r a l i z i n g E o l a t i o n s . The  veins  and g r e e n s t o n e  alike.  been c o n s o l i d a t e d before the  i n Keno H i l l The  sufficiently  faults.  p y r i t e , and long It  to p e r m i t o f f r a c t u r i n g a t or  time o f m i n e r a l i z a t i o n .  s o l u t i o n s f o r long  s i z e would  be  unlikely  to h o l d  t h e development  a e i d d y k e s c a r r y s m a l l amounts o f g a l e n a ,  tetrahedrite.  a f t e r th©  Moreover, the greenstone  periods, p a r t i c u l a r l y a f t e r  She  schists  g r e e n s t o n e s tauiit, t n e r e f o r e , have  b o d i e s by r e a s o n o f t h e i r s m a l l  o f the  area traverse quartzite  greenstones  As t h e s e v/ere n o t i n j e c t e d  until  -./ere c o n s o l i d a t e d , and e v e n  i s d o u b t f u l i f t h e g r e e n s t o n e s had  any  sheared,  e f f e c t on t h e i r  min-  eralization. Th© q u a r t z and  presence  o f c e r t a i n o f t h e o r e M i n e r a l s i n the  g r a n i t e p o r p h y r i e s suggests t h a t t h e s e r o c k s  have b e e n t h e s o u r c e o f t h e o r e d e p o s i t s .  I t i s not  may  thought,  however, t h a t these s m a l l b o d i e s o f a c i d i n t r u o i v e s caused e x t e n s i v e m i n e r a l i z a t i o n o f Keno K i l l ,  but r a t h e r t h a t they  the and  59. the m i n e r a l i z i n g e o l a t i o n s h a d  o f magfaa* Hill,  their origin i n a larger  body  A l a r g e mass o f g r a n i t e ooeurs to. t n e e a s t o f Keno  and  o t h e r nasaes o c c u r a l o n g a l i n e r u n n i n g n o r t h w e s t  southeast*  and  I t i s p r o b a b l e t h a t t h e s e r e p r e s e n t t h e peaks o f a  B a t h o l i t h w h i c h e x t e n d s under, much o f Mayo a r e a ,  f h e age  of  t h e s e g r a n i t e s h a s n o t been c l o s e l y d e t e r m i n e d , owing to t h e l a c k of sedimentary r o c k s .  They have u s u a l l y been c o n s i d e r e d  contemporaneous with the Coast range f r o m J u r a s s i c  Range i n t r u s i v e a w h i c h  t o Upper C r e t a c e o u s .  The  i n Yukon  ore d e p o s i t s  are  y o u n g e r , b u t c a n n o t be p l a c e d more d e f i n i t e l y w i t h r e g a r d t o  • fh. 1 t e h o r s e All probably  foraed  Batholith. t l a e and  time.  Two  known ore  District.  d e p o s i t s o f -tffcitehorae d i s t r i c t  l a t e r t h a n the I n t r u s i o n of the Coast  This I n t r u s i o n probably  possibly continued through  M c C o i m e l l , li* G.  have .iange  took place i n l a t e Jurassic a part of L e e r  c o n t r a c t i n g t y p e s o f 'deposits  jaetamorphic and  age.  Cretaceous  o c c u r , — contact  hydro t h e r m a l •  "Whitehorae C o p p e r B e l t "  Ueoi.Jurv.Gaa.  1909.  C a i r n e s , D» .D«, U c o l . j u r v . J a n . , Lera. 5 1 , 19.1& • C a i r n e s , J3» I u , "iCconoaio P o s s i b i l i t i e s o f Yukon" J ' .... . :„ ) Can. l a s t . l&e.t. T r a n s , v o l • ..iVIII, i?« b3, 1915.) tf. S. C o c k f i e i d and  A. H.  Bell.  G e o l . o u r v . C a n a d a , Kern.  150) }  "W'hi t e h o r a e D i s t r i c t , Y u k o n . "  )  CO. . C l a s s i f i c a t i o n o f Deposits. Deposit. Antiraony Silver  Occurrence  Mineral a s s o c i a t i o n .  I n Coast Mange I n t r u s i v e  Gangue c h i e f l y  rocks and i n C h i e f t a i n  q u a r t z ; b a r i te and  H i l l andcsites and v o l -  c a l c i t e subordinate.  canic b r e c c i a s .  Otibnite, sphalerite. Jameson!te, arsenopyri te, tetrahedrlte.  Gold-Silver  C h i e f l y i n Coast Range  wiar t z, c a l c i t e ,  Intrusive3, also i n  galena, p y r i t e ,  s c h i s t s of Kount Stevens  c h a l e o p y r i t e , gold  $N>up.  sylvaiiite.  Occur as f i s s u r e  fillings. I n Laberge r o c k s , a s  Quartz, c a l c i t e ,  Silver-  raetasoaatic  galena, a r s e n o p y r i t e ,  Lead  ments, geodea and  sphalerite, pyrite,  vu^s common.  chaleopyrite.  At contact o f Coast  Magnetite, s p e c u l a r ! t e  Contact-  Range I n t r u s i v e a w i t h  c h a l e o p y r i t e , quartz,  Met amorphic.  country r o c k , c h i e f l y  c a l c i t e , epidote,  limestones.  a c t i u o l i t e , garnet,  replace-  wollastonite, llmonlte, a z u r i t e , malachite occur i n o x i d i z e d zone.  61.  .fho -contact aetamorphio d e p o s i t s . a r e c h i e f l y c o n f i n e d  t o a narrow b e l t about 15 m i l e a l o n g , p a r a l l e l t o Lewes r i v e r i n the v i c i n i t y o f " J h i t e h o r s e .  The l a r g e r aggregates  of m e t a l l i c  minerals occur i n limestone or along the contact o f l i m e s t o n e and g r a n i t i c rocks., b u t numerous s m a l l bodies and s c a t t e r e d  g r a i n s are found wholly enclosed i n g r a n i t e and many a r e a t a considerable distance from th© l i m e s t o n e . The development o f n o n - m e t a l l i c m i n e r a l s i f probably g r e a t e r i n tne g r a n i t e than in. the l i m e s t o n e , and the areas a f f e c t e d are w i d e r and more ex-  t e n s i v e . . I n -places t h e o r i g i n a l contact i a c o m p l e t e l y obscured owing to the replacement  o f both rocks by s i m i l a r minerals.-The  .extensive and s i m u l t a n e o u s m i n e r a l i s a t i o n o f both the i n t r u d i n g and intruded rock say be e x p l a i n e d by assuming that i t was e f f e c t e d by hot s o l u t i o n s moving upward and taut i t took place a f t e r magma h-id s o l i d i f i e d t o some depth.  The ro placement o f  ore m a t e r i a l o f . g r a n i t i c dykes connected w i t h the main g r a n i t e area i s a l s o s i g n i f i c a n t i n t h i s c o n n e c t i o n . Contact aetamorphio e f f e c t s such as the  raarmorization  and s l l i f i c a t i o n o f l i m e s t o n e were noted by .Dr. w. K. C o c k f i e l d a t v a r i o u s p o i n t s i n the e a s t e r n h a l f o f J h i t e h o r s e d i s t r i c t ,  but nowhere were associated d e p o s i t s o f m e t a l l i c minerals i n evidence,  f h e only o t h e r ore d e p o s i t o f t h i s type known i n t h e  area I s t h a t s i t u a t e d cn the Fleming claim i n frieaton d i s t r i c t , f h e o r e m a t e r i a l s occur i n hornblende gneisses o f tne L'ount Stevena group { p o s s i b l y o f Pre-Cambrian age) near t h e i r contact w i t h the Coast Range I n t r u s i v e s .  I t i s c l e a r from the published data t h a t there has been  a period o f m i n e r a l i z a t i o n i n vJMtefcorsc d i s t r i c t c l o s e l y  fol-  68.  l o w i n g the i n t r u s i o n o f the Coast Range g r a n o - d i o r i t e n .  Ores  o f r e s u l t i n g type are g e n e r a l l y supposed to have been intruded  under c o n d i t i o n s o f high teciperature and high pressure and i n this  respect  contract s t r o n g l y w i t h other types of ore deposits  i n the r e g i o n .  The a v a i l a b l e evidence p o i n t s to a l a t e Juras-  s i c or e a r l y Cretaceous age  f o r the i n t r u s i o n of the g r a u o - d i o -  r i t o , and hence i t nay be concluded that t h i s f i r s t c a e t a l l c - • g e n i o epoch a l s o b e l o n g s i n t h e Upper J u r a s s i c .  The ore deposits o f V/hl t e n o r se d i s t r i c t , other than the contact r s e t a a o r p h i c d e p o s i t s , have teen c l a s s i f i e d by i n t o t h r e e d i v i s i o n s , g e l d - s i l v e r , a n t t s i o n y - s i l v e r , and lead v e i n s .  cairnes silver-  Of t h e s e , the- f i r s t clase i s " o f wide d i s t r i b u t i o n  i n southern-. Yukon and  c o n s t i t u t e s . the major p o r t i o n o f the  ore  d e p o s i t s , not o n l y of ;/heatoja d i s t r i c t but a l s o c f .Vlady a r e a  d i s t r i c t tc the s o u t h e a s t . " The  g e n e s i s o f these t h r e e t y p e s c f v e i n d e p o s i t s  has  'been d i s c u s s e d by Cairnes i n h i s memoir on the #<heaton d i s t r i c t .  The  conclusions  reached are.;  (1) That they have a l l been d e p o s i t e d .by a s c e n d i n g  hydrothermal  . s o l u t i o n s emanating from un i n t r u s i v e magma below.  (2) That they belong i n the ''upper v e i n zone," t h u t i s , they have been d e p o s i t e d under c o n d i t i o n s o f r e l a t i v e l y lov# tempera-  ture and  pressure. These concilia!ona are bused on:  i o n s ; and  (1) n i n e r a l a s s o c i a t -  {2) the f a c t that the w a l l - r o c k I s a l t e r e d only  slightly. From the evidence so far accumulated tae exact g e o l o g i c a l age of the format ion o f tho throe types of vein deposits  cannot be d e f i n i t e l y d e t e r m i n e d *  That they are o f c o n s i d e r a b l y  l a t e r age t h a n the contact joetaraorpiiic d e p o s i t s seems to be i n  l i t t l e doubt.  They a r e younger than the period o f s o l i d i f i c a -  t i o n o f at l e a s t a pr.rt o f the g r a n i t i c magma, and they anted a t e the e r u p t i o n s grouped under the head o f Hewer v o l o a n i c s .  T h i s evidence tends t o she?; a l a t e J u r a s s i c t o e a r l y  tertiary  age f o r these d e p o s i t s , and depends upon tne l e n g t h o f time r e quired f o r the c o o l i n g and s o l i d i f i c a t i o n o f the B a t h o l i t h . That the i n t e r i o r o f t h e B a t h o l i t h remained i n a heated and f e r -  t i l e c o n d i t i o n f o r a c o n s i d e r a b l e p e r i o d o f time there can be l i t t l e doubt.  The t h r e e d i f f e r e n t  types nay or nay n o t be c o n -  temporaneous; a s i m u l t a n e o u s o r i g i n can v * e l l be presumed by a s -  c r i b i n g t h e i r d i s t r i b u t i o n s i n zones to d i f f e r e n c e s i n . t h e parent magma, a case o f magmatic Hegregacion.  The d i s t r i b u t i o n o f ore d e p o s i t s i n .-/hitehorse d i s t r i c t show3 the s i g n i f i c a n t f a c t t h a t they are a l l close to the borders o f a r e a s o f g r a n i t i c r o c k s .  This f a c t s h o u l d be borne i n  mind i n f u t u r e p r o s p o c t i n g ©ork i n .fnitehorse  district.  F a r t h e r south on t h e other a i d e o f tne p r o v i n c i a l boun-  d a r y , I l e a the A t l i n d i s t r i c t .  Since i t s geology  and mineral  deposita a r c t r e a t e d i n considerable d e t a i l i n P a r t I I I o f t h i s p a p e r , we w i l l pass o v e r i t a t present.  I t may be w e l l to say a t t h i s place though, that i n general there i a much s i m i l a r i t y between tne deposits o f A t l i n and  t/hitenorse d i s t r i c t s .  T a i a i s no doubt due to the g r e a t  s i m i l a r i t y o f the general geology o f the two d i s t r i c t s .  64. Taku It 1 ver Are a. i  Kofc very raueh g e o l o g i c a l work has been done i n Tajku River Area, and what has been done, was uosfcly i n the way reconaissanee  work..  of  However, the more important f e a t u r e s are  already d i s c e r n i b l e . The Coast Range g r a n o - d i o r i t e b a t h o l i t i e rocks  consti-  t u t e the bulk of the loader urea of Taku Ri v e r , fro a i t s s o u t h t o v.-ithin b w i l e s west of the i n t e r n a t i o n a l oouadary-iine. There the contact crosses tac r i v e r , s t r i k i n g i n a n o r t h e r l y d i r e c t i o n , and apparently  f o l l o w s t h i s course about 6 a i i e s  west of the Tulaeguah R i v e r .  The roeka eaat o f the  contact  c o n s i s t mainly o f tiv* o l d e r Igneous groups, p r o b a b l y T r i a a a i c or J u r a s s i c , with some lltae stone and a l t e r e d sed 1 me a tar i ca. This o e r l a a i a i a t r u l e d - by youager r h y o l l t e , d a c i t e , and  fel-  a i t c dykes aad s i l l s which In turn arc intruded by basic rocks of lamprophyro typo. F o l d i n g and evidence o f acute s t r e s s i s observed near the c o n t a c t west o f the I n t e r n a t i o n a l boundary.  Easterly t h i s  c o n d i t i o n i s g r a d u a l l y s'dniaized, una the s t r u c t u r e , A e l l defined i n c e r t a i n l o c a l i t i e s , assumes the more stable and character that would bo conducive to the confined  definite  circulation  o f m i n e r a l i z i n g s o l u t i o n s and the d e p o s i t i o n o f sustained o r e bodies.  Taku HI ver D i s t r i c t , 3. 0.  ?• A. K e r r , b'uai. kept. 12 £2.  Taku R i v e r ..rea, J . T. Tfandy, P. C.  133.  M l n l s t . o f i'.lues, Rept.  1929,  65. F a j o r f r a c t u r i n g , aooomnatiled  i n p l a c e s by w e l l - d e f i n e d  s h e a r i n g , has o c c u r r e d a l o n g b o t h a n o r t h - e a s t e r l y and a n o r t h westerly  direction. The  m i n e r a l i z a t i o n of the c h i e f ore-bodies,  according  t o Dr. Mandy i s o f two main t y p e s : — (1) Cooper, z i n c , l e a d , and i r o n s u l p h i d e s c a r r y i n g a p p r e c i a b l e g o l d and s i l v e r v a l u e s i n a l a r i t e , c a l c i t e , " q u a r t z gangue. (2) Antimony and i r o n s u l p h i d e s ,  vtith  very minor  q u a n t i t i e s o f c o p p e r , l e a d and z i n c , but c a r r y i n g d e c i d e d g o l d v a l u e s , and p r a c t i c a l l y  negligible  s i l v e r c o n t e n t s i n a q u a r t z ganga*.  Ore-Bodlea o f Type 1. The type.  T u l s e g u a h and K a n v i l l e o r e b o d i e s b e l o n g  These o c c u r r e n c e s a r e c h a r a c t e r i s t i c replacement o r e -  bodies I n shear-zones. p o r t i o n s o f the zones, sheared  to t h i s  I n p l a c e s , g e n e r a l l y i n the c e n t r a l t h e s u l p h i d e s have t o t a l l y r e p l a c e d t n e  rock. Two main d i r e c t i o n s o f f r a c t u r i n g o c c u r , one s t r i k i n g  n o r t h - e a s t e r l y and t h e o t h e r n o r t h - w e s t e r l y . The  shear-zones  o c c u r i n what appears t o be an i n t e r -  f o r r a a t i o n a l sheet o f a l t e r e d p y r i t i z e d r h y o l l t e i n an a n d e s i t l e c o u n t r y - r o c k o f dense t e x t u r e . The f o r m a t i o n has been s u b j e c t e d to c o m p a r a t i v e l y g e n t l e f o l d i n g a l o n g n o r t h - s o u t h s t r i k i n g  axes.  The  o r e b o d i e s o f t h i s type a r e p r o b a b l y medium t o low  temperature  d e p o s i t s , formed a t an a p p r e c i a b l e depth below t h e  o l d s u r f a c e from s l u g g i s h l y c i r c u l a t i n g s o l u t i o n s .  Replacement  probably emanated f r o n the c e n t r e o f the zones w i t h l a t e r a l temperature  segregations.  Mineral d e p o s i t i o n i s probably r e -  l a t e d t o the c o n c l u d i n g period o f t h e B a t h o l i t h O r e r i j o d i e s o f Type £.  intrusion.  (Sfeibnitegoid.) n  The o r e - b o d i e s o f t h i s type a r e c h a r a c t e r i s e d ' oy a main m e t a l l i c content o f a t l b n i f c e , w i t h accompanying py r 1te and  very  minor q u a n t i t i e s o f g a l e n a , l a a f l a e - g r a i n e u quartzose gangue. T h i s afcihaise o c c u r a i n a manoive g r a n u l a r form i n r e t i c u l a t e d s t r u c t u r e i n the v e i n m a t t e r , and «lso as a f i n e o f minute  needle c r y s t a l s i n the gangue-matter.  dissemination The p y r i t e i s  l a .fine g r a i n e d s c a t t e r e d d i i i s e m l i k t t i o n through the g<.nigue. The t y p i c a l o r e - b o d i e s of t h i s type appear  to be c o n f i n e d to a d i a -  baaie r o c k , cut by numerous f e l a l t e and s m a l l . p i a r t r h y o l i t e d„-kefj.  They seem t o f a v o u r the e r a a aomeehat eloaor be the  'Bathoiitjj c o n t a c t than the o r e s o f type I . i n »ell-defined replacement s i t e dykes.  The depesite  sheer-acnes alcaig the course o f f e l -  These dykes have prob..;bly formed  i n the surrounding c o u n t r y - r o c k -.long w h i c h  l i n e s o f weakness  thy f r a c t u r i n g  s h e a r i n g has been r e a d i l y c a r r i e d and s u s t a i n e d .  The  d e p o s i t s are c h a r a c t e r i s e d by a h i g h g o l d content and low s i l v e r v a l u e s ,  occur  and  typical abnormally  a d u l t e r a t i o n wi th a r s e n i c and copper seems  to be p r a c t i c a l l y absent.  These o r e - b o d i e s are p r o b a b l y of low  temperature o r i g i n , formed c o m p a r a t i v e l y near t h e s u r f a c e .  The  s t r u c t u r e i n d i c a t e s that they wore foamed from rj&apidiy c i r c u l a t i n g e o l a t i o n s c o v e r i n g at l e a s t two impulse p e r i o d s , although the d e f i n i t e g e n e s i s o f these depoaibs c o u l d not be e s t a b l i s h e d i n tne f i e l d , they a r e p r o b a b l y r e l a t e d to the f i n a l t h e r m a l  a c t i v i t i e s o f the b a t h o l l t h l e i n t r u s i o n ana o r i g i n than the ore-bodies of l e a d - z l n c - s i l v e r  later in  type,  S i t I k i n e a nfl^ I e k u t R i v e r A r e a . m  T h i s l a r g e and  little  s t u d i e d a r e a e x t e n d s from Taku t o  about TInuk I-Uver, a d i s t e n o e o f some 150 - 200 m i l e s . west i t i s b o r d e r e d it  On  by t h e C o a s t Range B a t h o l i t h , t o the  i s u n d e r l a i n by u n c l o s e i f led P a l a e o z o i c and, p r o b a b l y  Fesozoic rocks.  the east  some  I t seems t h a t e l l a l o n g the c o n t a c t , end  far-  t h e r f r o m i t , forming- a b e l t about £5 r i l e s w i d e , m e t a l l i c mine r a l s have been f ounff.  T h i s i s t o be e x p e c t e d .  However,  because o f the r e l a t i v e i n a c c e s s i b i l i t y o f the r e g i o n , comparatively l i t t l e The  p r o s p e c t i n g and development was  done.  work t h a t has been clone shows t h a t the d i s t r i c t  . m i n e r a l i s e d , and  t h a t more work i a  warranted.  j?. A. K e r r i n h i s r e p o r t on T t i k i n e R i v e r area !,  is  says;  There a r e f o u r d i f f e r e n t k i n d s o f d e p o s i t s found i n the a r e a : (1)  magnet!te-pyrrhodits  (Z)  zinc  (3) l e a d (4)  copper.  I n some p l a c e s the v a r i o u s k i n d s a r e c o m p l e t e l y t e d , whereas- i n o t h e r s two o r more k i n d s may m i n g l i n g or g r a d i n g i n t o one P. A. K e r r . "  "  '*  "  Sum. *  Rept. 1926.  be p r e s e n t  another." p. 14  0. S.  C.  «  1929,  p. 11  G. S.  C.  «  1929,  p. 30  G. 0.  C.  isolaInter-  68.  d e p o s i t s of t h e m a g n e t i t c - p y r r h o t i t e type appear t o l i e d i r e c t l y on t h e i g n e o u s r o c k o r In i t , rather than i n the sediments.  A l t e r e d sediments a r e g e n e r a l l y found associated  w i t h there, though i n some places t h e m i n e r a l i s e d messes seem to o c c u r as lenses i n t h e g r a n i t e i t s e l f . " This i s then a contact n e t s m o r p h i c type of d e p o s i t . '•'Galena and s p h a l e r i t e u s u a l l y occur intermingled o r c l o s e l y associated  ».  The m i n e r a l i s a t i o n i s g e n e r a l l y i n the sediments t t or near the contact....... Some d e p o s i t s are c l c e r l y replacements o f the sedi&ents by £ a ague and s u l p h i d e s .  iT  A l l these deposits are very s m a l l , and probably have no co«MPereiel importance.  The copper type of d e p o s i t , represents a l e n s - l i k e body of c h a l e o p y r i t e i n bedded limestone.  I t i s a l s o s m a l l and does  not exceed a fev* f e e t i n any d i r e c t i o n . Prom what has /been s a i d i t seems, that a l l these depos i t s are t o o f r a i l . , b.ixl too patchy to be o f any grest  interest.  however -choir p o s i t ion along the en s t e r n contact o f the B a t h o l i t h , i n d i c a t e s , that t h i s p o r t i o n o f t h e contact i s mine r a l i s e d , end thr-1 t h e r e f o r e there* i s no re©son why l a r g e r dep o s i t s r-hould not cn:j.3t.  It  OCO:J:3  c i o a r though, thnt the presence of m i n s r a l i s -  iin- bod-/, l i k e the B a t h o l i t h , i s not s u f f i c i e n t to produce l a r g e ore d e p o s i t s .  I t i a necessary  i n conjunction w i t h i t to  have s t r u c t u r a l c o n d i t i o n s which would tend t o concentrate t h e available ; • literals a t a point.  Salr<on__ P iyjtj? h^rSH* The Sainton R i v e r Area w i t h the n e i g h b o r i n g and  "Sear R i v e r  S t e w a r t R i v e r p.res has r e c e i v e d c o n s i d e r a b l e -amount' o f  attention.  Thin  'n p r o h * c l y due t o t h e f e e t t h a t t h e d i s t r i c t •  is f a i r l y a c c e s s i b l e and t h a t s e v e r a l p r o m i s i n g  ore d e p o s i t s  have been d i s c o v e r e d , — o u c h a s P r e m i e r , B i g M i s s o u r i , and D o l l y warden.  # Dr. S. J . S c h o f i e l d , i n h i s r e p o r t on the d i s t r i c t i n Kern. 132 o f t h e C o o l . C u r v . o f Canada thus summarises the economic g e o l o g y o f t h e a r e a ; " I n the mines o f Salmon R i v e r a r e a , t h e v a l u e s the p r e s e n t  have been m a i n l y i n s i l v e r  of the deposits  a ad g o l d , a l t h o u g h  c e n t 9 i n econo&ie q u a n t i t i e s o f g a l e a e ,  b l e n d s , c h s l c o p y r i t e , and - y r l t e  up t o many  sine  i n a *u&rtfc gangae, v;hich con-  s t i t u t e what I s known a s a complex s i l i c e o u s o r e . The m i n e r a l i s a t i o n o f the d i s t r i c t the 0 l o s i n g s t a g e s  i s associated  with  o f the Coast Range i g n e o u s a c t i v i t y — t h a t  p e r i o d •which has been so i m p o r t a n t i n idr i t i s h C olumbia •  i n c o m m e r c i a l ore . d e p o s i t i o n  ,?  The o r e d e p o s i t s a r e connected w i t h t h e ''Premier s i l l s . " These a r e t a b u l a r masses o f sitiartz p o r p h y r y i n t r u d e d the b e d d i n g p l a n e s o f the t u f f 3 o f the Bear R i v e r  between  formation.  Their, maximum t h i c k n e s s I s i n t h e neighborhood o f 1,300 f e e t . The r o c k i s g r e y m a s s i v e , and i n hand specimens shows i n some oases phenoerystt) o f o r t h o c l a s e and s m a l l , i r r e g u l a r masses o f q u a r t z i n a f i n e - g r a i n e d ground mass. $ S. J . S e h o f i e l d and G. Hanson, 0. a'. C.  l;em. 132.  70. The s i l l s were i n t r u d e d p r i o r t o the m o u n t a i n - b u i l d i n g , and,  t h e r e f o r e , w h i l e tii© t m f s  were h o r i z o n t a l .  S i n c e the time o f i n t r u s i o n , they have been s u b j e c t e d to f o l d i n g a l o n g w i t h t h e c o n t a i n i n g r o c k s , and now occupy v a r y i n g p o s i t i o n s which d e v i a t e from the h o r i z o n t a l . "The  o r e d e p o s i t s a r e o f t h r e e main, t y p e s : (1)  Base m e t a l  type  (£) S i l v e r - g o l d ( 3 ) Gold  type  type.  Base 'metai Type. The u s u a l moue o f o c c u r r e n c e replacement faceous metals.  o f t h i s type i s t h a t o f  and u i s a e m i n a t i o n i n c e r t a i n beds o f t u f f s and t u f -  conglomerates,  a l t h o u g h v e i n s o c c u r c o n t a i n i n g t h e base  The u e p o s i t a a r e roughly t a b u l a r , s i n c e they  correspond  i n s t r i k e and d i p w i t h t h e beus w i t h w h i c h they are a s s o c i a t e d . I n B i g M i s s o u r i r i d g e , t h e r e beds s t r i k e a l o n g the r i d g e and d i p a l a low a n g l e to 'the west and s i n c e the s l o p e o f the h i l l s i d e down to t h e Salmon  rtiver  g l a c i e r i s s t e e p e r t h a n the  d i p o f t n e t u f f a c e o u s beds, t h e m i n e r a l i z e d zones f o r m l o n g , l i n e a r o u t c r o p s on b i g M i s s o u r i r i d g e . c r o p s , c o l o u r e d brown by the presence  These weathered o u t -  o f i i . o n i t e , a r e a marked  feature o i the r i d g e . The m i n e r a l s p r e s e n t  i n obese bancs a r e p y r i t e , c h a l e o -  p y r i t e , s p h a l e r i t e , and g a l e n a i n a gangue o f q u a r t z . all  Pearly  the examnles of t h i s type o c c u r on B i g M i s s o u r i r i d g e .  groups o f c l a i m s from s o u t h to n o r t h a r e as f o l l o w s :  The  inaian.  B i g M i s s o u r i , H e r c u l e s , and K o r t y - n i e , a l l of which c o n t a i n m i n e r a l d e p o s i t s s i c - l l a r to the d e s c r i p t i o n g i v e n above.  71. The a l t e r a t i o n o r meiamorphlsm o f t h e r o o k s on B i g  M i s s o u r i ridge makes t n o i r uetermination very d i f f i c u l t , i f n o t impossible i n many eases, so t h a t the c o n t a c t between the q u a r t z porphyry ana the t u f f s was not d e f i n i t e l y recognizee, and i t i s c e r t a i n that over the g r e a t e r p a r t o f Big M i s s o u r i ridge t h i s c o n t a c t i s b u r i e d underneath  the t u f f s and the t u f f a c e o u s  congloracrates. S i l v e r Gold Type. The  ores of t h i s t y p e . o c c u r  replacements  i n veins and v e i n - l i k e  i n quartz-pornhyry ana a t the contact of the por-  phyry ana t h e t u f f s .  The l a r g e ore-chutes are l e n t i c u l a r .  The  minerals present a r e p y r i t e , c h a l c o p y r i t e , s p h a l e r i t e , galena, t e t i adieu r i t e , i r e i b e r g i t e , p y r a r g y r i t o and other  sulpho-antimo-  n i d e s and a u l p h o - a r e e n i d e s , n a t i v e s i l v e r , and gold.  The gan-  gue i s r a t h e r abundant and i s almost e n t i r e l y quartz.  The o r e -  b o d i e s of t h e P r e m i e r mine belong to t h i s type. r  fhe n a t i v e s i l v e r i s found almost e n t i r e l y associated  w i t h f a u l t s ana shear zones and was n o t seen i n the u n f r a c t u r e d vein material.  I n a d d i t i o n the f r a c t u r e s show a strong down-  ward movement of water and contain considerable amounts of limonite.  The s i l v e r o c c u r s as t h i n leaves o r p l a t e s f i l l i n g  s m a l l c r a c k s i n the ore.  Some occurs  i n h a i r l i k e forma (wire  s i l v e r ) and nuggets i n s m a l l quartz u r n s s e s . of  The l o c a l i z a t i o n  the s i l v e r to the imraeuiate v i c i n i t y of the f r a c t u r e s points  to a secondary o r i g i n f o r the n a t i v e s i l v e r , o r , i n other words, the  n a t i v e s l i v e r i s due to secondary enrichment.  72. Gold  Type.  A s i n g l e ore-tody In 1;o. 2 tunnel of the Premier Pine I s o f t h i s type.  I t i s a s i l i c e o u s , heavy sulphide d e p o s i t .  Quarts and ->jrite arc the p r e d o m i n a t i n g minerals,.  S a i a l l quan-  t i t i e s of c h a l e o o y r i t e , s p h a l e r i t e , and galena are present. Assays ©how high values i n g o l d , but p r a c t i c a l l y no s i l v e r . "  O r i g i n of ^the^Ores.  Dr. S c h o f i e l d considers that the o r e bearing s o l u t i o n s emanating from the g r a n i t e d u r i n g tne f i n a l stages o f c o o l i n g entered the f i s s u r e s and shear zones and a t favourable l o c a l i t i e s formed o r e - b o d i e s The  of c o i u & e r c i a l s i z e .  o r e - b e a r i n g s o l u t i o n s w h i c h foraou the ore  on B i g M i s s o u r i r i d g e e v i d e n t l y s p r e a d  l a t e r a l l y along favour-  able horizons i n tne t u f f s and t u f f conglomerates. c a s e s , as at the  the sheareu  bodies  In other  P r e t t i e r M i n e , the ore-bearing s o l u t i o n s  contact between the quartz porphyry s i l l s and  found  the  t u f f s a favourable p l a c e f o r ore d e p o s i t i o n . The eviaenee a v a i l a b l e points out, that t h i s occurred probably i n Upper J u r a s s i c tioie.  73.  Alice A r m  District.  The a r e a i s on t h e e a s t e r n b o r d e r o f t h e Coast Range B a t h o l i t h and t h e m i n e r a l d e p o s i t s a r e p a r t of t h e g r e a t  miner-  a l i z e d b e l t w h i c h extends w i t h few i n t e r r u p t i o n s a l o n g tno eastern contact.  An h i a t u s o c c u r s  i n t h e b e l t a t Bass R i v e r  where no m i n e r a l d e p o s i t s a r e known. A l i c e Arm i s a t the s o u t h e r n  ena o f t h a t p a r t of the  b e l t t h a t extends northward and t h a t i n c l u d e s the m i n s r a l dep o s i t s o f P o r t l a n d C a n a l , Unuk and S t i k i n e r i v e r s , and a t l i n . The  m i n e r a l d e p o s i t s o f A l i c e mrm d i s t r i c t can be  c l a s a i f i ea una o r f i v o h e a u l a g s : (1) M o l y b d e n i t e  deposits.  (2) High grade a l i v e r - b e a r i n g v e i n s i n a r g i l l i t e . (3) S i l v e r l o a d d e p o s i t s i n v o l c a n i c r o c k s . (4) S p h a l e r i t e ucoos i t s . (b) O h a l e o p y r i t a  deposits.  •£he h i g h grade s i l v e r b e a r i n g v e i n s i n a r g i l l i t e a r e quartz'veins 6 f e e t or less i n width, which are mineralized w i t h p r i nary e i l v e r mi n e r a i s .  I'h e s i l v e r - l e a d d e p o s i t s i n vo 1-  c a n i c r o c k s a r e v e i n l i k e , u s u a l l y much w i d e r than b f e e t , cons i s t o f q u a r t z , b a r i t e , ana country r o c k , and a r e m i n e r a l i z e d w i t h s i l v e r - b e a r i n g g a l e n a and t e t r a h e u r i t e . Owing to secondary enrichment some of the d e p o s i t s o f t h i s type c o n t a i n r i c h silver ore.  (George Hanson.  " M i n e r a l D e p o s i t s o f ^ l i c e Arm D i s t r i c t . "  Oeoi. S u r . Canada, Sum. K e p t . 19£8, p. Zl.)  74.  She s p h a l e r i t e deposits a r e v e i n - l i k e and c o n s i s t o f q u a r t z , c a l e i t e , - c o u n t r y rock, and r e s i n colourea s p h a l e r i t e , uepos i t s vary c o n s i d e r a b l y I n s i z e and are u s u a l l y i n 8eyrisentaiy r o c k s . The c h a l c o p y r i t e deposits a r e v e i n - l i k e and c o n s i s t of quarta, country r o c k , and c h a l c o p y r i t e . The d e p o s i t s are mostly i n volcanic rocks.  I n raany respects they c l o s e l y resemble the  s p h a l e r i t e deposits and say be c l o s e l y r e l a t e s  to them i n  origin. •'  Hanson concludes, that the deposits have not been  studied s u f f i c i e n t l y y e t , to be able to formulate any s a t i s f a c t o r y theory to account f o r the various d i s t i n c t types of mineral d e p o s i t s . The deposits are very numerous, and considerable work has been spent on development, but so f a r the D o l l y warden l i n e i s the only one which produced an a p p r e c i a b l e quantity o f metal (1,300,000 o z . of s i l v e r ) . , But soae as Hanson says, have outstanding . p o t e n t i a l i ties.  75. The Skeena and n e i g h b o r i n g  Districts*  A l a r g e body of n j r l te w i t h associated c h a l e o p y r i t e , occurs some distance up Ses t a l l R i v e r , but except f o r t h i s occurrence very few mineral deposits of importance are known between Prince Puoert and  Terrace.  Forth ana south of Terrace along the eastern border o f the main body of the Coast Range B a t h o l i t h , mineral veins are numerous.  bearing  TTo large ore bodies are known, but the  veins though narrow are commonly very r i c h .  They are  euartz-  sulphide veins c o n t a i n i n g f r e e g o l d , and the value i n a o s t instances i s almost en 11 re l y i n g o l d . A s h o r t distance east o f Terrace, b o r n i t e - f r e e g o l d quartz veins occur, as w e l l as other d e p o s i t s of a more complex n a t u r e .  East-and west o f Skeena- E i v e r , in the neighbour-  hood of F i d d l e r and L o m e Creeks, gold q u a r t z veins a r e again the r u l e .  In the v i c i n i t y o f Haze'lton are numerous s m a l l to  modernte-sizea veins containing a great v a r i e t y of a i n e r a l s , among which may  be mentioned gold, jamesonite, w a i f r a m i t e ,  s c h e e l i t e , molybdenite, s a f f l o r i t e and the common .minerals o f copper, l e a d , z i n c , s i l v e r , i r o n , and a r s e n i c . On Hudson Bay mountain the veins are mostly s m a l l , and are mainly o f the s i l v e r - l e a d t y p e .  Veins containing a r s e n i c  and gold are a l s o present. Hanson a l s o mentions a v e i n near Francois Lake which contains bitumen and phosphate minerals, but as l i t t l e i s  (0. Hanson. 0. S. C.  "Prince Rupert to B u m s Lake, ?.. C."  Sunra. R e p t l 19-24, p. 38.)'  76. known a b o u t i t , n o t h i n g more has t o be a a i d .  Fear Fasnelton o c c u r s an i n t e r e s t i n g deposit o f Tungsten, described by  E. K u r s t , In 0. 3. C. Suam. Rent, f o r 1924.  This d e p o s i t , together w i t h these o f a r s e n i c , copper-, l e a d , e t c . , occur i n Rooher D e t o u l e mountains, southeast of Eazelton, diorlte.  The deposit occurs along a shear zone, i n the granoPresence o f such minerals as wolframite and s c h e e l i t e  i n d i c a t e s high temperature and pressure c o n d i t i o n s . The  i n t e r e s t o f t h i s deposit l i e s mostly i n the f a c t ,  t h a t d e p o s i t s o f other than conventional type may be expected, f a r t h e r from the main Coast Range B a t h o l i t h , In connect.ion w i t h the  s a t e l l i t i c bathol I t h s , and that therefore the s a t e l l i t e s  warrant  more a t t e n t i o n than has been heretofore given them. •i Another mineral d e p o s i t , described by Lang  i s also  connecter w i t h a s m a l l s a t e l l i t i c b a t h o l i t h . The a epos i t s c o n s t i t u t i n g the Owen Lake mine, are v e i n s f i l l i n g shear zones and f r a c t u r e s i n the m i c r o - d i o r i t e and i n  included blocks o f a n d e r i t e . A s i n g l e v e i n , and replacement deposits i n the matrix of  conglomerate, are exposed on a prospect on T s a - l i t mountain.  Because of i t s proximity to the granite stock on Mount auina, rf  t h i s m i n e r a l i z a t i o n i s believed to be associated with the granitic  intrusion. The veins are roughly p a r a l l e l , f i l l i n g shear-zones and  fissures i n micro-dioriti.  They vary from mere s t r i n g e r s to  A . H. Lang.  "Uwen lake Mining Camp."  Rent. 1929.  p. A. n. 62.  C!. S. C. Suam.  77.  i r r e g u l a r l y m i n e r a l i z e d shear zones o f 5 to 6 f e e t w i d e . 2here a r e two g e n e r a l t y p e s of e h a l c o p y r i t e - s p h a i e r i t e and between the two  ffilitei'alization:  s p h a l e r i t e - g a l e n a , but ^ r a a a t i o n s  types occur, and  as y e t no  zonary arrangement  has been obaerved. The  c h a l o o p y r i t e - s p h a i e r i t e v e i n s rave hiah  c o n t e n t , and a moderate g o l d content. are:  r h o d o o h r o s i t e , quartz,  •:.  silver  The gangue m i n e r a l s  chalcedony,  and  barite.  -The s p h a l e r i t e - g a l e n a type c o n t a i n moderate s i l v e r v a l u e s ana a low g o l d c o n t e n t . b'he v e i n s a r e o f the e p i t h e r m a l o r i g i n , which i s supported  by the f o l l o w i n g  evidence:  (1) P r o p y l i t l z a t i o n i s a t y p i c a l a l t e r a t i o n accompany i n g enIthermal  deposits.  ( 2 ) Chalcedony Is a c h a r a c t e r i s t i c gangue m i n e r a l of e p i t h e r n a l v e i n s . (3) M e t a l l i c and gangue m i n e r a l s a r e of e p i t h e r m a l type.  The age o f the c \ i c r o - d i o r i t o s t o c k , with w h i c h the deposits  are a s s o c i a t e - ,  Lowe r Jn ra s s I e.  i s considered by T&jtir to be post-  78. quoting M a r s h a l l : — "As y e t v e r y l i t t l e  p r o s p e c t i n g has l e a n done i n t h i s  r e g i o n , and o n l y a l o n g p a r t s o f the t r u n k s t r e a m s .  The d i s -  c o v e r i e s s o f a r sa&e prove t h a t m i n e r a l d e p o s i t s o c c u r and t h a t t h e r e e x i s t s a t l e a s t one w e l l - d e f i n e d m i n e r a l i z e d of considerable  zone  extent.  C o l d , s i l v e r , l e a d , z i n c , and copper have been found i n v e i n s on C h i k a m i n r i d g e , s o u t h o f i ' J h i t e s a l l L a k e , and on Sweeney mountain n o r t h of Tahtaa r i v e r . The s i l v e r — l e a d — z i n c d e p o s i t s on C h i k a m i n ana Sweeney mountains a r e the i m p o r t a n t d i s c o v e r i e s so f a r made. iho s i l v e r - l e a d d e p o s i t s on Chikamin r i d g e ar@ i n beds of a l t e r e d and sheared w a t e r l a i n t u f f s which o u t c r o p n e a r a number, o f s m a l l i n t r u s i v e masses. i'hoae o f Sweeney mountain o c c u r both i n uiae s e d i m e n t a r y and v o l c a n i c members.  Ine most i n t e r e s t i n g showing, t h a t In  t h e Emerald group of c l a i m s d e s e r v e s more P e t a l l e u  description.  Sweeney mountain i s formed o f r o c k s o f the H a z e I t o n group, 11 t h o l o g i c a l l y s i m i l a r t o r o c k s o f the same group on Chikamin Ridge•  West o f the westernmost  the Coast Range i n t r u s i v e s group.  peak o f t h e mountain,  invade the members ••>£ tne H a z e l ton  The m i n e r a l d e p o s i t o c c u r s i n beds of sheared ana  a l t e r e d t u f f s and a r g i l l i t e s . Q u a r t z f i l l s f r a c t u r e s i n t h e t u l f a , f o r n i n g v e i n s up to 18 i n c h e s w i d e ,  -he q u a r t z i s f r a c t u r e d  J . R. i & r s h a l l , 7/hi te s a i l - ? a h t s & Lakes A r e a , G. 3. C. Sumn. Rept. 1924, p. £2 A.  in a l l directions, .  79. and t h e s e f r a c t u r e s a r e f i l l e d w i t h c u b i c a l and s t e e l galena, and- subordinate amounts of p y r i t e , c h a l e o p y r i t e and s p h a l e r i t e . She t o t a l l e n g t h of the d e p o s i t from a d i t p o r t a l to the orest of the r i d g e i s a t l e a s t 2,000 f e e t , and the d i f f e r ence i n e l e v a t i o n about 900 f e e t .  From. But suk l a k e to Chi loo l a k e . The e x t e n s i v e , s e v e r a l hur.dred miles long, t r a c t o f land from Eutsuk Lake to C h l l c o Lake has been very poorly prospected, and no great d i s c o v e r i e s have been made.  There a r e  only three p r o p e r t i e s that deserve some a t t e n t i o n . These a r e : {1} A deposit o f a u r i f e r o u s a r s e n o p y r i t e , s i t u a t e d about 2 miles north o f Perkins Peak. (2) A deposit of Hematite 1 mile south of Perkins Peak, and {3) The Morris mine o r the Tatlayoko Lake Gold Pines L t d . The g o l d - a r s e n i c deposit i s s i t u a t e d a t an e l e v a t i o n of 7,800 f e e t near the brow o f the steers, northward-facing s i d e o f the deep v a l l e y immediately  north of Perkins Peak.  ( J . R. Marshall,' But suk Lake area, B. C.  0 . 3 . C.  Suma. Rept. 1925, p. 144 A.) (?. DoImage. T a t l a - B e l l a Coola Area, B. C.  0. S. C.  Suam. Rept. 1925, p. 155 A.} (V.DoImage. C h l l c o Lake, B.C.  O.S.C. Summ.Rept. 1924, p.70 A )  80. The d e p o s i t i s reaehea by a branch t r a i l l e a d i n g from One Lake to P e r k i n s Peak. o f sedimentary  Eye  The ore b e a r i n g v e i n s o c c u r i n a s e r i e s  r o c k s composed of b l a e k a r g i l l i t e s , d a r k brown  a r g i l l a c e o u s sandstones,  and f i n e , c h e r t y conglomerates o v e r -  l a i n c o n f o r m a b l y by t h i c k beds o f coarse v o l c a n i c b r e e e i a w h i c h f o r m the summit o f P e r k i n s Peak. to  The s t r a t a s t r i k e n o r t h  70 d e g r e e s e a s t and d i p s o u t h e a s t 40 to 45 d e g r e e s .  found i n the near v i c i n i t y of the veins, are reported Lower Cretaceous age.  60  Fossils  to be of  The rocks are c u t by the Coast Range  B a t h o l i t h , the contact of w h i c h makes a U shaped bend around the southwest a i d e of Perkins Peak and i s £ miles  4§> mi l e a  southeast,  southwest, and l-.V miles northwest of the d e p o s i t s .  A s m a l l d i o r i t e s t o c k , l e s s than o n e - f i f t h of a mile i n diameter,  s i m i l a r to and probably a part of the B a t h o l i t h , outcrops  i n a small cirque *f mile southeast  of the d e p o s i t .  The mineral i s i n large quartz veins or  silicified  zones which s t r i k e north ana are n e a r l y v e r t i c a l and,  therefore,  extend up the steep v a l l e y w a l l . Arsenopyrite are q u i t e l a r g e , but  Is disseminated  i n quartz.  the amount of c o n t a i n e u gold  The showings unfortunately  i s small.  A deposit of e x c e p t i o n a l l y pure Hematite o c c u r s i n a large c i r q u e on the soutneast  side of Perkins mountain.  It is  s i t u a t e a near tne bottom of the cirque on the north side a t an e l e v a t i o n of 7,500 f e e t . One  I t i s reached by a good t r a i l  TTye Lake or E l i n a L k i n f i a t s , both on B e l l a Gooia  from trail.  61*  The Hematite occurs i n a bed of t u f f , which, with other types of v o l c a n i c r o c k , i s interbedded w i t h Lower Cretaceous s e d i ments,  fhe t u f f bed i s 10 to 20 f e e t thick and i s , i n p l a c e s ,  completely replaced by Hematite.  Small veins of quartz and  spsoalarite out i t and a d j o i n i n g beds.  The beds s t r i k e south  70 degrees east and d i p 20 degrees south.  The sedimentary and  volcanic beds l y i n g between the Hematite deposit and the cont a c t of the B a t h o l i t h , which i s about 1 mile to the south, are thoroughly  impregnated w i t h p y r i t e , and along c e r t a i n w e l l  developed shear-zone3 near the i r o n - b e a r i n g t u f f the rocks are completely a l t e r e d to t a l e and s e r i e i t e s c h i s t c o n t a i n i n g a l a r g e amount of p y r i t e .  The  r o 3 t important  deposit near Ohilco T.ake i s the  T a t i s y o k o L a k e G o l d i ' i n e , b e t t e r bnowa ae  th?- V o r r i s  aine.  Hie d e g o a i t l a s i t u a t e d 3 a l l e c sou t h e n s t o f t h e  end of 1 ' a t l a y o k o L a k e .  Zt  is  a t an  south  e l e v a b i . c n of 15,900 f e e t ,  Just above t i m b e r l i n e , and 3,200 f e e t a b o v e t h e l a k e , The  d e p o s i t oaar.lwfcs ">!' t h r e e q u a r t s v s l n a o u t c r o p p i n g  on t h e s i d e s o f a s t e e p r o c k y g u l c h .  The  veina cut  Trlassie  sediments, c h i e f l y a r g i l l i i e s a n t f i n e Baj.idatof.cn, but w i t h one  t h i n "bed of l i n e c h e r fey a on y l c r e r a t e .  a s n o r t distance  northeast o f the v e i n s i s a s t o c k o f q u a r t a d i o r i t e related  to t h e b o a s t  probably  'van-re dal.->.oli t h , the e d g e of w h i c h i s  s i t u a t e d a fet? miles t o the sou t h •  I'any d y k e s o u i the  ments and range i n composition from d i o r i t e to b a s a l t , m a j o r i t y being b a s a l t i c ,  biaay, i f not a l l ,  sedithe  o r e y o u n g e r than  82.  the v e i n s . The veins c o n s i s t of q u a r t z , through which i s d i s s e m i n a t e d f a i r l y evenly a r s e n o p y r i t e , p y r i t e , s t i b n i t e , and two or three undetermined minerals v i s i b l e only under the microscope, but whieh, Judging from the assays are probably s i l v e r bearing. These minerals a r e c l o s e l y a s s o c i a t e d w i t h the s t i b n i t e which tends to occur i n the c e n t r a l parts o f the v e i n s , whereas the g o l d , arsenopyrite and p y r i t e are more p l e n t i f u l along the margins.  The rock adjoining; the veins  has been a l t e r e d to a very dense g r e y i s h green m a t e r i a l resembling  chert.  83. Taaeko V a l l e y . L i m o n l t e i s found, i n th© Taseko V a l l e y .  The d e p o s i t s  are s i t u a t e d i n t h e upper p o r t i o n o f t h e v a l l e y and i n t h e v a l l e y s o f s e v e r a l t r i b u t a r i e s , t h e t o t a l area beds o f l i m o n l t e a r e found  i n which the  b e i n g about 50 square m i l e s .  The r o c k s u n d e r l y i n g the l i m o n l t e d e p o s i t s a r e a n assemblage o f b a s a l t i c f l o w s and p y r o c l a s t i c s w i t h some q u a r t z d i o r i t e p o r p h y r i t e dykes and s i l l s ,  the whole known as t h e  "'Taseko f o r m a t i o n . ' T h i s v o l c a n i c f o r m a t i o n o f T e r t i a r y age, o v e r l i e s unconformably t h e p r e v i o u s l y eroded surface of the great Coast Ra n ge Ba t ho 1 i t b . The  deposits kncrsn as b o g - i r o n  seven d i f f e r e n t l o c a l i t i e s .  ore, are s i t u a t e d i n  They c o n s i s t of sheets of brown  l i m o n l t e o f v e r g i n g shape, s i z e , end t h i c k n e s s , b u i l t up o f t h i n l a y e r s o f brown, c e l l u l a r , and g e n e r a l l y  loose-textured  l i m o n l t e l y i n g p a r a l l e l to t h e s u r f a c e o f the ground on w h i c h they r e s t .  The H c o n i t e  virion  dug forms a large percentage of  l i n e s ; rroct of i t breaking Into pieces o f leas than h a l f an i n c h , and each of i t breaking t o the fineness The  i r o n i s derived  of sand.  £ro/r f i n e l y divided p g r i t o which  impregnates g r e a t l y s i l i c S f i e d r-md s e r i c i t i z e d t u f f s o f t h e Taseko format i o n . ' The i r o n sulphate s o l u t i o n s formed by t h e o x i d a t i o n and l e a c h i n g of t h i s p y r i t e t r i c k l e down the mountsin s l o p e s a n d d e p o s i t a t the f i r s t favourable i o c a U . j n , b a i l d i n g uo s u e d o £ l l m o n i t e . J . D. IfacEenzie.' "The limonite deposits i n Taseko V a l l e y . G. 3 C. Su m. R e p t . 1920, p . 42 A. V  n  84.  Gun -Crsek Area. There ?re no producing (fines i n the Sun Creek area at present, hut severs 1 Lit e r e s t i n g copper and gold deposits occur The r.ost irrt o r i e n t drpoeS t& o f C~vn Creek erea, ere four grade coprer-golo  low-  d o g o s i t s , s i t u a t e d i n the Coast Range Pstho-  l i t h along I t s contact- with the Cretaceous v o l e a n i o s . The m i n e r a l i z e d part of the B a t h o l i t h i s a normal grano d i o r i t e composed of f r e s h andesine, hornblende, b i o t i t e , o r t h o c l a s e , and  magnetite.  The segregation  of the ore minerals  part of the B a t h o l i t h seems to  in t h i s p e r t i c u l a r  be dependent on the development  of p e c u l i a r o r b i c u l a r s t r u c t u r e .  The g r o n c a i o r i t e occurs as  nodules - or " p i l l o w s " from 10 to 18 inehec i n diameter, having w e l l f'or/ceu, smooth s u r f a c e s , but no v i s i b l e i n t e r n a l . r a d i a l or concentric t o x t u r e .  The  i n t e r i o r s o f the nodules c o n s i s t  o f normal massive g-rano&Iorite  s i m i l a r to the a d j o i n i n g  o r b i o u l a r parts of the B a t h o l i t h .  non-  The i n l ©modular p o r t i o n s  are made up of m i a r o l i t i c g r a c o d i o r i t e together with- quarts chaleopyrite.  The m i a r o l i t i c c a v i t i e s are l i n e d w i t h w e l l -  formed c r y s t a l s of q u a r t z , o r t h o c l e s e , lsamontite, and pyrite.  and  In places there i s considerable  chaleo-  chaleopyrite dissem-  inated i n the q u a r t z , and o e c a s s i o n a l l y blebs ol" t h i s copper mineral up to 3 inches i n diameter. sparsely disseminated  Chaleopyrite  i s also  i n the marginal portions of the nodules.  Small amounts of p y r i t e are associated with the c h a l e o p y r i t e . (V. Bolcage.  'Gun Creek Area, B. C."  Summ. Kept. 1928.  p. 78  A.)  C. S.  C.  85. l o g o l d o r s i l v e r m i n e r a l s have been observed i n the though a s s a y s show these m e t a l s to be p r e s e n t T h e deposit i s exceedingly  - The "The are®, and  sulphides,  i n s m a l l amounts.  low g r a d e a v e r a g i n g  l/> i n copper.  Bridga River Area.  most I m p o r t a n t ore d e p o s i t s of t h e B r i d g e  River  i n f a c t the e n t i r e L i l l o o e t m i n i n g d i v i s i o n of  i s h C o l u m b i a , are the g o l d - q u a r t s  deposits.  ft  But t h i s i s .not the o n l y type of d e p o s i t s and d e p o s i t s may  Brit-  the  be c l a s s i f i e d a s f o l l o w s : —  (1) G o l d q u a r t z  deposits,  id)  deposits.  P l a c e r gold  , ( 3 ) S l i v e r copper d e p o s i t s . ( 4 ) Ant iruouy d ep osi ts • •  ( 5 ) Chromite d e p o s i t s . (6) H i c k e l - i r o n d e p o s i t s . I?) I l o n - m e t a l l i f e r o u s d e p o s i t s . I n t h i s paper we  are only c o n c e r n e d w i t h the. m e t a l l i -  f e r o u s d e p o s i t s of the l o d e t y p e , end p l a c e r d e p o s i t s ana The  so w i l l d i s r e g a r d  the  the n o n - m e t a H i e s .  g - o l d - q u r r t z d e p o s i t ? o f the C a f l w a i l n d e r Creok b e l t ,  o c c u r as v e i n f i l l i n g s  i n w e l l defined f i s s u r e s i n an s u g i t e -  d l o r i t e stock. The B o r n e , C o r o n a t i o n  n.nd P i o n e e r mines ore l o c a t e d  t h i s body. (P. S. PeCann,'  ;,  Geology end ? ' i n e r a l D e p o s i t s  R i v e r Map-area, B . -C."  G. S  #  C.  i i e m o i r 130,  of t h e 1922.)  Bridge  on  86.  Many of th© sheeted  structure i n  i m p o r t a n t f i s s u r e s of the d i s t r i c t show Vuu'u  thw waiii* o i the v e i n s contain p a r a l -  l e l j o i n t i n g planes which a r e t h e m s e l v e s p a r a l l e l t o the. main x'is&ures.  The  compressive f o r c e s a c t i n g i'roia the west, which were  r e s p o n s i b l e f o r t h e f o l d i n g and c r u m p l i n g o f t h e Cadwailader s e r i e s on t h e w e s t e r n l i m b o f th©  Bridge River a n t i c l i n e , could  have produced i ' i s s u r l n g s i m i l a r to t h a t noted  i n the a u g i t e -  diorite. The  v e i n s are f i l l i n g s o f w e l l developed f a u l t f i s s u r e s  i n the a u g i t e - u i o r i t e *  The;/ a r e c h a r a c t e r i s e d by frequent  pinches and s w e l l s a l o n g t h e i r e n t i r e l e n g t h .  Those of g r e a t -  e s t economic importance d i s p l a y a banding or r i b b o n s t r u c t u r e  due t o subsequent :.\o\ ament along the plane of t h e v e i n s , and the s h e e t i n g of the quartz veins along what may of origin© 1 sulphide d e p o s i t i o n .  have been l i n e s  The h y d r o t h e r m a l  solutions  have had a profound e f f e c t upon the v / s l l - r o c k close to the  fis-  sure, having a l t e r e d i t t a a l i g h t c o l o u r e d , .greasy-feeling r o c k c o n t a i n i n g p y r i t e and ai«enopyrite i n . c r y s t a l s .  The gacgae minerals are: .quarts, s i d e r i t e and  dolomite.  The  calcite,  sericite,  m e t a l l i c m i n e r a l s e r e : £Old, w h i c h  occurs as p a r t i c l e s scattered through the quartz of the v e i n s , anrt so/retimes i n r i c h l y concentrated ore shoots or p o c k e t s ,  where I t i s e a s i l y seen vrith naked eye.  Sometimes i t occurs as  t h i n p l a t e s o r c o a t i n g an aiikenalded p a r t i n g s iii sheeted o r ribboned v e i n s .  I t alfco o c c u r s f i n e l y d i s t r i b u t e d  the sulphides i n minute f i l m s and  particles.  throughout  Free m i l l i n g g o l d  87. i s found a s s o c i a t e d wi th p y r i t e , a r s e n o - p y r i t e ,  chaloopyrite,  t e l l u r i u m m i n e r a l s , and s t i b n i t e , and a l l these m i n e r a l s  are  found to he u s u a l l y I n d i c a t i v e of the presence of high values of gold i n the The  veins.  presence o f t e l l u r i u m i n d i c a t e s t h a t t h e  may he classed  &s g o I d - t e l l u r i u m  deposits  type of d e p o s i t s , and i t would  be i n t e r e s t i n g to compare them w i t h the s i m i l a r deposits' f a r t h e r n o r t h , l i t r e , f o r instance, The  the Engineer F i n e , i n A t l i n  district.  v e i n s are o x i d i z e d to a depth o f about 100  There haa been movemont along the planes of the  feet.  veins  since thoy 'were formed, bub the dimensions o f t h i s movement v;ere s m a l l . Til e s o l u t i o n s from 'which the v e i n mater in I s were p r e c i p i t a t e d are  believed  to be g e n e t i c a l l y r e l a t e d to the a u g i t e -  d i o r i t e i n t r u s i o n , the veinv  c o n s t i t u t i n g the r e s u l t of the  l a s t phase of ; ngmatic d i f f e r e n t let ion wi t h i n the m?u;m8 from :  which v7ao derived the a u g i t e - d i o r i t e * A s u f f i c i e n t length o f t i.^.s avvat. hnve intervened between  the I n t r a c i o a of the a u - I t e - d i o r i r e and  the Tarnation of  the v e i n s , to have permitted of the s o l i d i f i c a t i o n of the i n t r u s i v e ta such an extent that i t mould y i e l d to atreiiBea  deforcing  by Irac t a r i n g . The a u g i c e - d l o r i t e  has been i n t r u d e d by l i g h t - c o l o u r e d  a l b i t i t e porphyry d y k e s w h i c h are considered to- be a d i f f e r e n t i a t e o f the  a u g i t e - d i o r i t e magma, and  later  the v e i n s  s e l v e s , \3hich eut across these d y k e s , are believed  them-  to have been  the l a s t m a n i f e s t a t i o n of igneous a c t i v i t y of the i n t r u s i v e ,  88. a n d , t h e r e f o r e , of t h e  saj-t-  g e n e r a l age as t h e a u g i t e - d i o r i t e ,  lint, s l i g h t l y younger t*rr> *A..r t". ; i x r , The a u g i t e - d i o r l ^ e  iz such s o r e metamorphosed than t h e  J'erilo::? gurii't:;~cliorito w h i e h . I D o n l y 2g- m i l e s away, a n d t h e qunrtsi-diori•:';<•: doon n o t c o n t a i n g o i d - q u s r l z v e i i m . uiori  Ls n o t known to .have i n t r u d e d f o r m a t i o n s  The a u g i t e -  y o u n g e r than  t h e Ga&wa U n d e r s e r i e s , w h i c h l a U p p e r T r i a s s i c a g e , w h e r e a s the  Senior g u n r t z - d i o r l t o Intrudes  C r e t a c e o u s ago•  The o.ug:l.te-«:liorite, t h e r e f o r e , on a c c o u n t o f  i t s lithological characters, relation  s e d i m e n t s o f known l o w e r  i t s g r e a t e r m o t o m o r g h i s m , MB& i t s  up i n t r u d e d f o r a a t i o n o ,  i s considered  t o be o l d e r t h a n  the Bendor ba t h o l i t h i o ''quar i i a - d i o r i t e , ana i t s age i s p l a c e d as l a t e  Jurassic.  Sllyer-Copper  Pe^sit  In v i e w o f d i f f i c u l t i e s  o f t r a i l apor t a t i o n ,  climatic  c o n d l t i o n n , a n d the l o w t e n o r o f t h e ore i n e i g h t , the c o p p e r s i l v e r d e p o s i t s have n o t b e e n a c t i v e l y d e v e l o p e d . "he most p e r s i s t e n t  v e i n o f t h i s t g o e i s f o u n d on t h e  s i d e o f : " e O i i l i v r a y m o u n t a i n , whence i t way be t r a c e d a mile  f o r over  northwestward. I t d i s p l a y s - banded s t r u c t u r e  f i s s u r e by c r u s t i f l e s t i o n .  due t o f i l l i n g o f the  The m e t a l l i c m i n e r a l s have been  d e p o s i t e d i n t h i n , bonded *ggre.-*3ton p e r s l l e l t o t h e we l i s . *Comb S t r u c t u r e * and drr.sy cavi t l e s r e n d e r t h e v e i n to s u r f a c e r a t e r s , w h i c h h.-ve p e n e t r a t e d  permeable  i t , thereby causing  89. the o x i d a t i o n of the t e t r a h e a r l te.  The r e s u l t i n g  carbonates  of copper, a z u r i to, snu i . . & l a o k i U , nave stained the quartz to a. marked degree. ilia gaague miaera 1 i s e n t i r e l y quartz^ and contains tetrahedrite  f  a z u r i Le, malachite and galena i n asiall amounts.  i.*i oc the miner a l l a y t ion of the v e i n and i ts f i e l d r e J  l a t i o n s , i t i s probable that i t via a formed at intermediate depths and iz g e n e t i c a l l y r e l a t e d to the i n t r u s i o n of the Bendor u u a r t z - a i o r i t e , the v e i n m a t e r i a l s being the expression of the l a s t phase of igneous a c t i v i t y . The s i l v e r i s contained i n the galena, which, as f a r as i s known, occurs i n but s m a l l ©mount.  Antimony Ttepoa:!ts. - The antimony d e p o s i t s a r e c l o s e l y r e l a t e d to the i n t r u sion of d i o r i t e - p o r p h y r y dykes.  The ore occurs i n a quartz  garigue In shear s ones bordering the dykes and i s d i s t r i b u t e d f o r the nost part In i r r e g u l a r .1 ens-sheped masses through quartz. They appear to be confined to a narrow b e l t on the western limb of the Pridge River a n t i c l i n e , and have been found only w i t h i n the Fridge Rir- er s e r i e s .  the  90. Chromite J D e p o s i t s .  A s s n l l deposit o f ohromi<m ope o c c u r s on the northern slope of T a y l o r b a s i n i n the northwestern  corner of t h e raap-  area.  I t I s a s s o c i a t e d w i t h a s m a l l o u t c r o p of s e r p e n t i n e  rock.  Occurring as f i l m s . a l o n g the f r a c t u r e planes, and as  f i l l i n g s of c a v i t i e s In the e h r o s i t e i s a w h i t s , compact hydrated s i l i c a t e of fiagneoias. M o r o s e o p i c diamonds were found In the c h r o a i t e . The c l o s e a s s o c i a t i o n of the c h r o M t e t i n e rocks p o i n t s t o a g e n e t i c r e l a t i o n s h i p . represents a be s i c c once-it, rat ion  with  the serpen-  I t undoubtedly  by ^agnatic d i f f e r e n t i a t i o n  w i t h i n an o r i g i n a l l y oli'Td ne-hold i n - m r n a , the oiiroir.ite probably b oj.ng the f i r s t metc< 13J e n i n o r a l to e r y s t e l l i K e , , The s n a i l diamond n which a r e ir.: header: r i t l i n i t , i.aiei have c r y s t a l l i z e d out f i r ? t of a l l and represent d i s s o l v e d carbon i n the molten &e>;mn»  91.  C o q j u i h a l i a A r e a , B. G. S t r i c t l y s p e a k i n g , t h e C o q u i h a l l a a r e a s h o u l d n o t be i n c l u d e d i n t h i s t h e s i s , s i n c e I t l a y s o u t s i d e t h e Coast Range and belongs t o the Cascade Range.  But a s i t shows t h e same  p r o p e r t i e s as the o t h e r u e p o s i t s of B r i t i s h C o l u m b i a , i t was  decided to g i v e a b r i e f d e s c r i p t i o n of the economic geology o f t h i s area,  x o l Lowing 0. Hi. C a i r n e s ; — ?  "The economic minerals axm metals i n t h e i r decreaoing order o f imports „neo i n c l a d e ; molybdenite,  present  g o l d , s i l v e r , copper,  a r s e n i c , platinum, l e a d , manganese, and i r o n .  They occur i n both d e t r l t n l and l o d e d e p o s i t s ,  i n the former  g o l d n n l platinum nr.3 tho only M i n e r a l s o f importance. "die lode deposits o f c c K m e r c i r l value Include;  gold,  s i l v e r , copper nud r olybdennm. f-oIci ores HP<? t h e r-ost. im..« o r i e n t t r.d c h a r a c t e r i s t i c o f the d i s t r i c t .  They oo o\v i n %va d i s t i n c t l y oept rsr te s e c t i o n s  o f the crea j-nd. i n q u i t e d i f f e r e n t g e o l o g i c a l e s e o c i e t i o n s . T h e i r mo:vt important veins i n the  &evel< g^ent i s confined t o gold-quartz  ;,ner si?,to b e l t end the u n d e r l y i n g andesite  greenstone member n f the Crone Creek s e r i e s .  Their o r i g i n i n  the v i c i n i t y o f the ninta acme, at i s a t t r i b u t e d t o & large d i o r i t e i n t r u s i v e which c l o s e l y f o l l o w s t h i s contact.  Other  g o l d quart *a veins seem, ho .•••ever, to bo g e n e t i c a l l y r e l a t e d t o s n n l l e r and nore a c i d p o r r n y r i t i c dykes and g i l l s ,  (G. K. Cairnes. G. S. C.  intruding  " C o q u i h a l l a .Area, B r i t i o h Columbia."  Memoir 139. 1924.)  98. the slates.  The q u a r t z TTCH- ,; occur a s combinations f i l l e d and  replacement vein.type.  Thoy are e o ^ o n l y bedded w i t h the s l a t e s  or occupy i r r e g u l a r fi.is,;rs;.i i n e i t h e r s l a t e s or greenstones, fhap a l s o occur i n s h a t t e r '/-ones i n e i t h e r o f • the se roohs and appear a s a network of l i n k e d v e i n l e t s f o r m i n g a zone many yards wide and p e r s i s t e n t over many hundred and ...•ossioly t h o u -  sand f e e t ,  i n a l l these types, g a l a values are v e r y  irregu-  l a r l y d i s t r i b u t e d , out i r e eo/n^onlg highest where a r s e n o p y r i t e , and  t o a l e s s extent p y r i t e o r c h a l e o p y r i t e ^ p© most abundant. R  The  ganguo eonnlots of «ilkg \?hi te c-uart'/,,  Xth i n  some casoo a l i t t l e c a l c i t e and a s t i l l s m a l l e r proportion o f aibite.  Sulphide n i n o r o l s nre dir?so::.insted c i t h e r i n  Segre-  gates of f i n e g r a i n s ox- pn I r r g e r i r d i v i d u o l c r y s t a l s , b u t never i n s o l i d w s s e a .  They f no luce.- p y r r r . o t i t e , ...yriio,  arsen-  o p g r i t e , /.:rd c b r l e o p y r . l f s , nr-.r.ed. i ' i order of elr-nndaiu-e, and Pyrrhotito- i s , hov;ever, not txz eo&>;,orj i n the  deposition.  quarts v e i n s themselves as i n the s,aJoiniiJg w a l l - r o o k .  Very  l o y a l l y s n a i l proportions of g a l e n a , blendo, aiid s t i b n i t e are encountered. and  Gold i s c h i e f l y associated  w i t h the a r s e n o p y r i te  o c c u r s e i t h e r i n the f r e e s t a t e o r so f i n e l y wixed o r  i n t e r g r o w n w i t h t h i s or other sulphides as t o be even m i c r o s copically  invisible.  Gold ores a l s o occur a t the /sufeas mine where the ore minerals  a r e massive a u r i f e r o u s a r s e n o p y r i t e .  and p y r i t e are associated The m i n e r a l s  Chaleopyrite  i n v a r y i n g amounts i n a quartz gangue.  occur i n w e l l - d e f i n e d v e i n s  i n a moderately coarse-grained,  o c c u p y i n g shear zones  basic p l u t o n i e rook that v a r i e s  93. f r o m q u a r t z - d i o r i t e t o d i o r i t e and i s r e g a r d e d a s o f Upper J u r a s s i c a g o . i h c v e l a a a r e ad i n t e r m e d i a t e c h a r a c t e r as r a g a r d s d a t a t e m p e r a t u r e and d e p t h o f f o r m a t i o n .  Arsenopyrite  i s a u i ' f i o i e n t i y auunuaak ana massive i n c h a r a c t e r  to j u s t i f y  i t s separate treatment f o r a r a e n i c . deposits the  i s referreu  older p l u t o n i o  She o r i g i n ox these o r e  to b a t h o i i t h i c i n t r u s i o n s which i n t e r s e c t rocks. X  Silver ores are of present a t the E u r e k a  comme re i a l  V i o t o v i f c .mines on b i i l v s r peak,  importance  only  b n e y o c c u r as  v o i n d e p o s i t s o f i n t e r n e d i n t e a n d l o w t e n nern t a r e s i n .fracture nones f o l l o w i n g J o i n t d i n a a r ^ n merate. in thin  i.n n :--t-«.s«ive C r e t a c e o u s  ?he g n n - n e i a c l u d e a .? i d a r i t e , order- of d e c r o w n i n g a l u n d r n c e .  conglo-  I t m o / s i t e , a n d qv.arts The p r i n c i p a l o r e  minr-rnX "J:- an : g g o n i f f . r o u a t c t n a h ' . ; d r l -a- c-;.rrging i. v a r y i n g R  proportion  of l e a d .  S e c o n d a r y c o n c e n t r a t i o n o f . t h e v e i n m a t e r i a l hy surface waters  has r e s u l t e d  i n the d i f f e r e n t l s l  enrichment  v e r a n d 3end nt t'-e esrpenee o f the o t h e r m e t a l l i c minerals. theso  Values  v e i n deposits  * Cairnes,  C. n .  and g a n g a e  up t o gVOO n t a c h a v e b e e n obtained  enriched shoots  primary  of the s i l -  o r ore p o c k e t s .  from  A v e r a g e v a l u e s i n the  v e r y up t o ebout ,GO, b u t a r c ne a r u l e  i'.sm, 1 3 9 . 1924.  94.  The only copper ores o f economic v a l u e o c c u r a t t h e Independence mine,  l i i e y form v e i n s and replacement d e p o s i t s  i n f r a c t u r e s or f i s s u r e s i n a l a r g e g r a n i t e porphyry dyke cutt i n g t h e E a g l e g r a n o d i o r i t e and rocks of the Tulameen group. T h i s property was examined by C a m s e l l who regarded d e p o s i t s as s t r o n g l y resembling the Butte type.  the ore  The gangue  includes a l t e r e d g r a n i t e porphyry and secondary q u a r t z , c a l c i t e , and s e r i c i t e .  The p r i n c i p a l ore mineral i s c h a l e o p y r i t e ,  but p y r r h o t i t e and p y r i t e a r e a b u n d a n t and some c h a l c o c i t e , c u p r i t e , blende, and molybdenite were observed.  Tetrohedrite  i s a l s o reported t o o o c u r here. One important molybdenite d e p o s i t has been discovered on the Dominion t ' i r e r a l Group i n the Cretaeeous g r a n i t e on the summit west o f l e g o .  The sn.lphiOe occurs i n a high temperature  quarts ler-s o f i>e--vatitle o r i c i n and i s a l s o iiaoi'e.gnated through t h e a d j o i n in-: g r o r J L t o .  The .aiolgbdonite o c c u r s i n l a r g e  flakes  and lumps i n t h e ,i;arU a/id i n d j sse&int'ted t r a i l e r f l a k e s i n the c o u n t r y rook, has occurred,  homo i ocoadi' rp oo-.idati >n t o ye H o w  f o other o r e mine r a l s v;ere oh nerved»*'  i.,olybdite  95  i r t i i i i Dis c r i c t .  96. Atlin  .District..  Physiography. t v o uis»!>inctAy u l i f e r e n t  x'ha A v l i u dt«3vri.ot *rs* ..jv>ii piaysJ.ograpb.ic p r o v i n c e s .  Une i a t h a t of t h e C o a s t xtange, a n d  tne o t h e r t h e xitkoji p l a t e a u , i h e C o a s t ^ange i s e s t r e a t l y r a p p e d , c o n s i s t i n g Ox k n i f e l i k e r i d g e s , n e e d l e s u b m i t s , and a b r u p t l y v a l l e y s , and everywhere c o n s i d e r a b l e seen t h r o u g h o u t t h e e n t i r e  iaainly-  incised  i c e and snow a r e t o be  year.  The Y u k o n P l a t e a u i s a g e n t l y u n d u l a t i n g u p l a n d w h i c h i s b e s t viewed from a summit a t o r n e a r t h e e l e v a t i o n o f t h e plateau surface.  f r o , j such a p o i n t  t h e o b s e r v e r i s s t r u c k by  the n e a r l y l e v e l c h a r a c t e r o f the upland siveeping avay i n a l l d i r e c t i o n s t o t h e h o r i z o n and b r o k e n o n l y h e r e and t h e r e by isolated  r e s i d u a l m a s s e s thv.l r i s e abov« t h e g e n e r a l l e v e l .  T h i s h o r i z o n t a l ~ar£*:?oe r i g h t  i n p l a c e r be t a k e n f o r & s u r f a c e  o f c o n s t r u e t.1 on, b u t i t i s r e a d i l y  seen t h a t i t t r u n c a t e s  a l i k e r o c k s o f v.-idely v a r y i n g d e g r e e s o f r e s i s t a n c e . land  stands a t an average elevation, o f £,000  The up»  feet.  f i i e t r a n s i t i o n from t h o p l a t e a u t o t h e C o a s t fenge i i o u n t a i n s y s t e m i s v e r y grac.ua 1, BO crucb i o ^ t h a t i t i s , i n places, d i f f i c u l t  t o d e t e r m i n e where one ends and t h e o t h e r  begins. The w i d e d i f f e r e n c e b e t w e e n t h e t o p o g r a p h y o f t h e C o a s t Range and t h a t o f t h e Yukon p l a t e a u seems t o be due m a i n l y t o three causes.  In the f i r s t  p l a c e , t h e C o a s t Range i s composed  l a r g e l y of massive g r a n i t i c  r o o k s w h i c h do n o t p o s s e s s b e d d i n g  97. p l a n e s , n o r a l t e r n a t i n g hard and s o f t l a y e r s t o be emphasized by e r o s i o n , so. t h a t &u'fc-&wial a g o n o i e s have had no r e g u l a r c o n t r o l and have thus produced v e r y e r r a t i c f o r m s .  The  irregu-  l a r j o i n t i n g p l a n e s i n t h e s e r o c k s have a l s o i n p l a c e s a s s i s t e d i n the p r o d u c t i o n o f b o l d I r r e g u l a r t o p o g r a p h i c f o r m s . d l y t h e g r a n i t i c r o c k s a r e h a r d e r and erode l e s s r a p i d l y  Seconthan  the r o c k s o f the p l a t e a u a n d , t h e r e f o r e , have caused t h e Coast Range i n t h i s d i s t r i c t t o r e t a i n a g r e a t e r g e n e r a l e l e v a t i o n t h a n the r e g i o n t o the en f t . ' t h i r d l y , s i n c e , f o r various reasons i n v o l v i n g d i f f e r e n t i a l e r o s i o n and u p l i f t , the c o a s t Range i s no** higher than the r l n t e n u r e g i o n , i t s t i l l contains g l a c i a l i c e , although' the g l a c i e r s have l o n g ago v a n i s h e d from the p l a t e a u r e g i o n . Thus once a l i n e of dnmarcnnl ^a was e s t a b l i s h e d between the Be tv/o t e r r a n e s , t h e i r f e a t u r e : ! have stesd i l y become more and more contrasted. I t i n b e l i e v e d t h a t t h e region has auffered s e v e r a l c y c l e s of u p l i f t nnd e r o s i o n .  During J u r a s s i c , the C o a s t Range  B a t h o l i t h wr.s intruded and t;.o ( o a s t Range atooa h i g h . eous s ? r a p e r i o d of e r o s i o n .  Cretac-  -„uoilag " c h o f i e l d ; ^  '"T hroaghout tnc Gratacoou;;, thoae four gree t mountain c h a i n s , Vancouver I n l a n d , <" ueen C h a r l o t t e I aland Range, the Coast Range of B r i t i s h C o l u m b i a , the d i o r r a Revada Range, the C o l u m b i a - S e l k i r k Range and the i * l a s k i d e s , as w e l l a s C a e o a d i a , were a r e a s ox e r o s i o n , s u p p l y i n g sediments on both f l a n k s o f # • S . J . S c h o f i e l d . The g e o l o g i c a l r e c o r d of the C o r d i l l e r a i n Canada. T r a n s a c t i o n s o f the -Royal Soc. o f Can. V o l . X V I I , 1923, Sec. I V .  98. these highland  masses......*  The  i n C r e t a c e o u s i ' o r i a a t i o n 01 n* o.i* t n e g r e a t J u r a s s i c m o u n t a i n  g r a n i t e p e b b l e s which o c c u r prove t h a t the g r a n i t i c  sores  c h a i n s were a t t h a t time u n r o o t e d .  E r o s i o n and a e d i i o a n t a t i o n w i t h a l i t t l e v o l c & n l s m tinued, e l i i o s t w i t h o u t i n t e r r up t l on u n t i l the Lara/aide tion in early Tertiary  merged by cluded  of C r e t a c e o u s r o c k s i n the v a l l e y s i n the  i i a n g o , s u c h a..- t h o s e o f ' f c r r i a u n Lake a n a  h i v e r , shows t h a t the the c l o s e  c o a s t r.ange cay  kitscx&alluffi  have been i n p a r t  o f the C r e t a c e o u s ,  t h a t the foui- g r e a t J u r a s s i c  from  mountain  period.'  sub-  t h i s i t &ay chains  duced t o a c o n d i t i o n a p p r o x i m a t i n g p e n e p l a n a t i o n by of the Cretaceous  revolu-  tune,.,.,"  'fiie p r e s e n c e Coast  con-  be  con-  were r e the  close  1  " I n e a r l y T e r t a i r y t i m e , o s o g e n i c movements o f p r i m a r y importance  " t h e l a r a m i d e r e v o l u t i o n * a f f e c t e d the  of the C o r d i l l e r a and  the "rent P l a i n s . f  o f t h e g r e a t J u r a s s i c n o u n t a i n c was ne?; c y c l e folded for  of e r o s i o n while  snd formed  the f i r ? r t  peneplaned s u r f a c e  u p l i f t e d , thus s t a r t i n g  a  t h e bj-.eins o f s e d i m e n t s t i o n were  mountain  c h a i n s , than producing f o u n t a i n s  rev i o n w h i c h o oca peu  the f o l d i n g  of  the  revolution."'  O v e r c o n s i d e r s Ole p o r t i o n s S u r f a c e has b e e n a l m o s t ana  region  t i u e i n i h o c c c e r t e o f t r e I n t e r i o r P l a t e a u and  t h e hookp M o u n t a i n JuraSBide  nev  The  #10le  the  i f n o t v o l t e d e s t r o y e d by l a t e r  i n s u c h p l a c e s the t o c o g r a p h y  t r i b u t e d , rounded  of the d i s t r i c t ,  h i l l s , ma-y  plateau erosion,  c o n s i s t s of i r r e g u l a r l y  o f them g e n t l y  c o n t o u r e d and  diswith  summits t h a t a r e i n many c a s e s r e m a r k a b l y u n i f o r m i n e l e v a t i o n .  99. Two  .  main v a l l e y s o l i.he d i s t r i c t are o c c u p i e d by Taku  Arm of I'a^ish Lake, ana nflj.a Lu/.e. join, the main v a l l e y a .  duiat-. rdHsu oroas v a l l e y s  Very often the so eroaa v a l l e y s are a l s o  submerged, or have small e uparate l a k e s , or rnmnanta o l l a k o s , streams ana marshes. l'neae v a l l e y s «ere apparently old stream channels, which wore l a t e r a c c e n t u a t e d ay g l a o i a t i o n . The main ica-uaa^ea occupied the maattsr  depressions  such as A t l i n Lake, and both atraightened and planned t h e i r s l o p e s , and widened and lowered, t h e i r f l o o r s , produced were wide, deep ana steep s i d e d . places f i l l e d  The v a l l e y s thus  The i c e a l s o , i n  the f l o o r of the v a l l e y s with g l a c i a l  silts,  sands and g r a v e l s , boulder s l a y s , e t c . f , >, Cairnes considers that the formation of such T  lakes as Taku bra and. Tutohl Lake, v/hich, non occupy the p o r t i o n s of the valley-tartuomn tnyt aere l a s i occupied b.y these g l a c i e r s , i s owing to the f a c t that the i c e r e t r e a t e d up the v a l l e y s so r a b i d l y that only the lower portions wore - f i l l e d with g l a c i a l d e b r i s , causing reversed slopes and e f f e c t u a l l y impounding the water above. ? o H a w i n g 3. J . Cairnes,;  'The  ' i f shaped, s t e e p - w a l l e d  character o f . a l l the main v a l l e y s , and t h e reversed slopes of many, c a u s i n g l a k e s to form i n them, are due, m a i n l y at l e a s t ,  to g l a c i a l a c t i o n . The upwarp of the d i s t r i c t , gave the streams renewed l i f e and energy, and they immediately began v i g o r o u s l y s i n k i n g " D. D» C a i r n e s , Ifem.' 37, G. S,  C.  100. their c h a n n e l s  i n the u p l i f t e l s u r f a c e .  Seep V aksn neft * ncf  T'loi v i t D c c n c t i n e , \:tvc to  1*x»rp 1 £3  onr  1  _  Throughout the a r e a  RIP.d e,  sret t ^ e r e  5n  invnc c-S by g l o c i e r s fi'On the noun t a i n s  the t-ovith, nouthunnt ana v;est, v.-hieh have profoundly  effec-  ted the topography of the d i s t r i c t . 'dften a oroaa ioe~nh.ee t covers a d i s t r i c t , i t i .ode r a t e s the t o p o g r a p h i c f e a t u r e s and  neuueos the r e l i e f , by  eroding  m a t e r i a l f r o n thn h i g h e r o l s v u t i o n n and d e p o s i t i n g I t i n the d e p r e s s i o n s , hut where tko inn occupies o.nl.y the vs. 3 l e y s , as was  t h e cane o\er the g r e a t e r part of A t l i n d i s t r i c t much g r e a -  ter  r e s u l t s are seen and of a d i f f e r e n t bind; the Intel-stream '  areas aiainfain t h o i r even character iinaii'eotea by i o e , w h i l e ike  v a l l e y s arc widened and  produced  deepened, th** naxiaiun e l i e c t b e i n g  in. areas which have been previously prepared to r e c -  eive the i c e 'by having deep v a l l e y s already iaaae i n which the lee  can operate.,  p r e p a r e d , snd  faku arm  b e l t i s believed to have been so  i n i t V-shaped v a l l e y s have been transformed  wide, deep "TP  1  shaped d e p r e s s i o n s , and hanging v a l l e y s ,  into  cir-  ques, r o c h e s montormees, snd ether well-known n l a e i s l forms hove been produced," Hanging v a l l e y s f o r e a very conspicuous feature of the entire district.  t a i n , and  B e a u t i f u l ennnyien arc found on A t l i n moun-  ir. a l l v n t l e y s .  So.xe of those hang lay v a l l e y s are at l e a s t 2,000 f e e t above the Lotion, of the :.,ain v c l l e y s . Cirques are a l s o y a i t e frequent;  even i n the lower and  101. s o f t e r contoured i l a t e a u r e g i o n numerous c i r q u e s o f v a r i o u s s i z e a r e found on a l m o s t a l l mountains feet  s t a r t i n g w i t h 5,000  elevation. In some of them t h e snow does n o t i.-.elt the whole  mer  t  sum-  v/hile some become s o u r c e s of s t a l l streams and i n a few  c a s e s i n f i n i t e l y b e a u t i f u l l a k e s appear a t the end o f the summer. Of  p a r t i c u l a r i n t e r e s t a r e t e r r a c e s which a r e found i n  almost a l l the v a l l e y s of the d i s t r i c t . V a r i o u s reasons were advanced  f o r t h e i r occurrence.  C a i r n e a e x p l a i n s them by darning of the Yukon by r e t r e a t i n g i c e ; but C o c k f i e l d d e n i e s t h i s because  the t e r r a c e s do not seem to  have c o r r e s p o n d i n g e l e v a t i o n s i n d i f f e r e n t p a r t s o f the c o u n t r y , and t r i e s to e x p l a i n the f o r m a t i o n o f t e r r a c e s by the a c t i o n o f the i c e i t s e l f .  Atlin  District.  G e n e r a l Geology. A g r a n t v a r i e t y o f r o c k s , both sedimentary and and r a n g i n g i n are from Pre-Cambrian  igneous  to Recent, o u t c r o p i n the  A t l i n d i s t r i c t , and d i s t r i c t s n o r t h of i t i n the Yukon. As the same rocks o u t c r o p both i n the Yukon and A t l i n d i s t r i c t i t was  c o n s i d e r e d b e s t t o adopt t h e  the  classifica-  t i o n proposed by C o c k f i e l d , as b e i n g based on more r e c e n t snd d e t a i l e d work. (W. S. C o c k f i e l d and A . II. B e l l — h ' h l t e h o r a e D i s t r i c t , Yukon. G e o l o g i c a l Survey of Canada, Uem.  150.}  103. f a b l e of Formations. Era.  Period.  gonnation. Superficial  Quaternary  deposits,  Llthologlcal  Characters.  G r a v e l , sand, b o u l d e r c l a y , s i l t . , much m o r a i n e ! materials, volcanic  ash,  soil. A c i d .Vol-  R h y o l i t e , g r a n i t e por-  oanlcs  phyry, r e l a t e d v o l o a n i c s , with associated  tuffs &  breccias lie war  Tertiary  vol-  oanics.  Andesite,  basalt, & re-  l a t e d dyke r o c k s , Chafa-  La*  prophyre ?} w i t h a s s o c iated tuff3 & breccias. Upper Jur-  C o a s t Hange  G r a n i t i c rocks  assic  Intrusives.  i n c o m p o s i t i o n from g r a -  or  ranging  n i t e to d i o r l t e , wl th  Later.  associated  porphyritio  phases. Older v o l -  Andesite,  eanles  & related voleanios associated  1'esozoic  Jurassic  tuffs  basalt, with  and  breccias.  Lower and lliddle  diabase,  Tantalus  C o n g l o m e r a t e , w i t h sand-  conglomer-  s t o n e , s h a l e & seams o f  ate  coal.  Laberge s e r i e s . . . A r g i l l i t e ,  shale,  sandstone, arkose, greywaoke. t u f f , c o n g l o m e r a t e .  103. Table o f F o r m a t i o n s , ( c o n t d . )  Ira.  Period. Triassie  Formation. Limestone  L l t h o l o g l e a l Characters. Limestone more or l e a s  Cor, and)  doloaitie  Carboniferous(?) Palaeozoic  _ Taku group  Devonian(?)  S l a t e s , eherty  quartzite,  etc Gold s e r i e s  Pyroxenite, p e r i d o t i t e  (.IL. Pre-  Mount S t e v a n s  CafflhrianC?)  group  S e r i c i t e and c h l o r i t e s c h i s t , mashed b a s i c t o semi b a s i c v o l c a n i c s , gneissoid  uuartzltea,  hornblende g n e i s s , and limestone.  104. A t l i n D i s t r . Geology. D e s c r i p t i o n of  Formations.  Mount S t e v e n s Group, f h e Mount S t e v e n s group i n c l u d e s a number o f members w i d e l y d i f f e r e n t i n a p p e a r a n c e , c o m p o s i t i o n , and p o s s i b l y i n age.  They a r e , however, a l l o l d and  t h e i r mode o f o r i g i n and  so e x t r e m e l y a l t e r e d t h a t  succession are obscured.  They c o n s i s t  of s e r i c i t e and c h l o r i t e s c h i s t s , g r e e n s t o n e  schists,  q u a r t z i t e s , g n e i s s o i d o u a r t z i t e s , hornblende  g n e i s s e s , and  stalline  sericitic cry-  limestones. lio f o s s i l s have been c o l l e c t e d from any o f the members  of t h e ilount S t e v e n s group and t h e r e i s c o n s e q u e n t l y no d i r e c t e v i d e n c e as to t h e i r age, but f r o m the evidence a f f o r d e d by l a t e r igneous r o c k s which c u t them, they are i n a l l p r o b a b i l i t y the o l d e s t r o c k s i n the d i s t r i c t .  Cairnesg i n h i s l a t e r  work along, the i n t e r n a t i o n a l boundary, n o r t h of Yukon R i v e r , was a b l e to demonstrate t h a t the s c h i s t o s e r o c k s o f t h a t r e g i o n were p r e - m i d d l e ( ambrian and i n a l l p r o b a b i l i t y i r e Cambrian I n The  age. r o c k s o f the group occur i n the westermost p a r t o f  the d i s t r i c t , c l o s e t o the c o n t a c t of t h e main Coast Range Batholith.  They o u t c r o p around F a n t a i l L a k e , then c r o s s Taku  arm below Golden Gate and extend i n a narrow b e l t a l o n g Edgar and Tie I s on Lakes to the end  o f T o r r e s c h a n n e l , nnd beyond where  t h e y f i n a l l y d i s a p p e a r under the L l e w e l l y n G l a c i e r . # C a i r n e s , 2). D.  "Yukon A l a s k a I n t e r n a t i o n a l Boundary.  G e o l . S u r v . Canada, Bern. 67, p.  40-44.  rl  105.  Gold S e r i e s . Pyroxenlte and P e r i d o t i t e . fhe  pyroxenites and p e r i d o t l t o s are found i n the  c e n t r a l part of the d i s t r i c t , grouped i n g e n e r a l around the town of A t l i n .  The main body extends from the shore of A t l i n  Lake up the v a l l e y o f Pine Creek and then northward, t i l l i t meets the o l d limestones a t head waters o f Fourth of J u l y and C o n s o l a t i o n Creeks.  On one s i d e the formation i s cut by  g r a n i t e of the Leonerd mountain B a t h o l i t h . Smaller masses o f these rocks are scattered over the district.  The more important are found on A t l i n f o u n t a i n and  Chikolda Mountain. The rock as a whole i s very massive and no major s t r u c t u r a l f e a t u r e s were noted except J o i n t i n g and f a u l t i n g , n e i t h e r of which l a very prominent. Fresh surfaces i n some cases appear g r a n u l a r , and i n others no g r a n u l a r texture i s v i s i b l e .  The rock i s dark green  to black i n c o l o u r . The weathered surface i s coarsely p i t t e d and has a b r i g h t - r e d d i s h brown colour duo to presence of i r o n oxide.  106. Taku Group. fh© name Taku group ima proposed, by C a i r n e s , f o r a s e r i e s o f c h e r t s , s l a t e s and. c h e r t y q u a r t z i t e s , which have been r e f e r r e d t o t h e Cache Creek group o f t h e s o u t h e r n I n t e r i o r o f B r i t i s h Columbia. These r o c k s occupy a l a r g e p o r t i o n o f t h e d i s t r i c t . They a r e bounded by t h e £. C. Yukon boundary i n t h e n o r t h , A t l i n Lake i n t h e w e s t , l a k i n a R i v e r i n t h e south  and T e s l i n  Lake i n t h e e a s t . I n t h e c e n t r a l p a r t the s e r i e s i s c u t by s a t e l l i t i c b a t h o l i t h s , and s n a i l a r e a s o f l i m e s t o n e s , v o l c a n i c s , and t h e Gold s e r i e s . Harrow b e l t s o c c u r on t h e west s i d e o f A t l i n L a k e . The slates.  members o f the Taku group a r e m a i n l y  c h e r t s , and  The c h e r t s range i n c o l o u r from dark grey to b l a c k ,  but i n p l a c e s they a r e r e d d i s h on weathered s u r f a c e s , due t o o x i d a t i o n o f s m a l l amounts o f c o n t a i n e d  iron ore.  The r o c k s  a r e m a s s i v e , h a r d , nnd b r i t t l e a n d break i n t o sharp edged, i r r e g u l a r l y shaped f r a g m e n t s . The  r o o k s o f the Taku group u n d e r l i e t h e C a r b o n i f e r o u s  (?) B r a i b u r n l i m e s t o n e s and appear t o correspond w i t h t h e members o f Lower Cache s e r i e s , o f more s o u t h e r l y p o r t i o n s o f B r i t i s h C o l u m b i a ; they have t h e r e f o r e been c o n s i d e r e d probably  to be  o f Devonian age.  { C a i r n e s , D. D., G e o l . S u r v . of Canada, I em. 37, p. 53-53) ( G w i l l i m , J . C. " R e p o r t on A t l i n M i n i n g D i s t r i c t , G.5.C. Ann. Rept. V o l . I l l , p t . B, p. 17)  ! f  107, Braeburn  Limestones,  "Braeburn l i m e s t o n e s occupy the e n t i r e northeastern corner of Taku Arm b e l t and are e x t e n s i v e l y developed  thence  to the north and east... They thus extend up Tsku arm to the mouth of T u t s h l r i v e r on the west shore, and continue s o u t h e a s t e r l y to include the n o r t h e a s t e r n part of Peninsula mounts i n , ana the h i l l s Immediately  to the east of Sunday peak.  These limestones ore g e n e r a l l y f i n e l y t e x t u r e d and range i n colour from g r e y i s h blue to a 1, oat w h i t e . The name *Breeburn limestones'' was f i r s t a p p l i e d i n the  Braeburn-  i  Kynocks a r e a , '" from where these rocks have been traced c o n t i n uously to Taku Arm b e l t .  These limestones are a l s o the same as  those included under the Upper Cache Creek s e r i e s of Conrad mining d i v i s i o n . Dr. Dawson c o l l e c t e d F u a i l i n a e from the limeatones which extend along the east s i t e o f Windy arm, showing these beds at l e a s t to be Carboniferous, so the whole s e r i e s i s thought probably to belong to t h i s a r e , although no other f o s s i l remains of a d e f i n i t e character have been discovered, (D. D. C a i r a e s , 1'em. % C a i r n e s , D. D.  37. G. S. C.  P.53.  " P r e l i m i n a r y memoir on the Lawes end B o r -  d e n s k i o l d R i v e r s c o a l d i s t r i c t , Yukon T e r r i t o r y . " S u r v . , Dept. of t l i n e s , Can.  Mem.  ho.5,  Geol.  1910, p, 28-30.  108. Laberge The Laberge  Series.  a e r i e s i s the most e x t e n s i v e g e o l o g i c a l  t e r r a n e i n Taku Arm b e l t , ana i t s members o u t c r o p i n a g e n e r a l way throughout  the c e n t r a l , s o u t h w e s t e r n a m  northwestern  p o r t i o n s o f the d i s t r i c t . The  group of h i l l s e a s t o f Taku arm and south o f Graham  I n l e t ; t h e g r e a t e r p a r t o f t h e a r e a n o r t h o f F a n t a i l Lake and s o u t h o f T u t s h i L a k e , on t h e w e s t s i d e o f Taku arm; and Sunday mountain ana the w e s t e r n p o r t i o n o f Taku mountains,  are a l l  l a r g e l y composed o f t h e s e r o c k s . The T a n t a l u s c o n g l o m e r a t e s w i t h t h e Laberge conformably.  nre probably best included  s e r i e s , because they o v e r l i e t h e Laberge  rocks  I n Wheaton d i s t r i c t , where t h e most d e t a i l e d work  done i n t h e d i s t r i c t was u n d e r t a k e n , and where t h e b e s t  expos-  i  u r e s o f t y p i c a l l y marine s e d i m e n t s  occur, Cairnes  ?J  recognized  a t h r e e f o l d d i v i s i o n o f the Labr^-ge bees, ea f o l l o w s , o r i f , as i n t h e p r e s e n t c a s e , t h e T a n t a l u s conglomerate fourfold  \*> i n c l u d e d , a  division: T a n t a l u s conglomerate; Conglomerate, Laberge  t h i c k n e s s 1,800  feet. -  s h a l e , s a n d s t o n e , and c o a l ,  Series;  TJpper beds; t h i c k n e s s 1,500 f t . sandstone Middle ; * 1,700 f t . s h a l e s , s . s . , a r k o s e . Lower "» ; 1,800 f t . a r k o s e s & t u f f s w i t h „ shales 3 conglomerates. 1  total * C a i r n e s , D. D.  6,800 f t .  '^heaton D i s t r i c t '  1  G.3.C. Mem. 3 1 , p. 54-56.  109. Following  Cockfieid:— ' ' F o s s i l s have been c o l l e c t e d fro® the Laberge beds i n  Wheaton, A t l i n , Tfhitehorse and T a n t a l u s a r e a s .  I n the c o l l e c -  t i o n s from T a n t a l u s a r e a , t h r e e forms a e r e s p e c i f i c a l l y  iden-  t i f i e d , v i z . T r i g o n i a Daws on i , I l e r i n e a mandensis, and Rhynchonella O r t h i d i o i d e s .  The specimens were r e g a r d e d by .  v/hit eaves a s J u r a s s i s o r C r e t a c e o u s but two I f n o t a l l t h r e e of these s p e c i e s a r e now r e g a r d e d as J u r a s s i c F o s s i l s c o l l e c t e d by G w i l l i m r e p o r t e d on by S t a n t o n as f o l l o w s :  forms.  In A t l i n d i s t r i c t were  "These may p o s s i b l y be  T r i a s s i c , b u t 1 t h i n k i t more p r o b a b l y that t h e y a r e e a r l y Jurassic.  They a r e c e r t a i n l y not as l a t e as the Cretaceous '."' 1  ^Thus i t appears to be v e r y w e l l e s t a b l i s h e d  that the  Laberge beds range i n age from middle Lower J u r a s s i c t o lower fiddle  Jurassic.  G w i l l i m , J . C ; G. S. C. Ann. R e p t . V o l . I l l , p t . 3,  r  p. 23-27 (1899). ^ » « C o c k f i e i d and A* H. B e l l . w  E  G. S. C. Kern. 150, p. 2 2 .  "Whitehorse  D i s t r i c t , Yukon.  tT  110. Older V o l c a n i c s . These rocks are t y p i c a l l y compact, f i n e l y textured, and dark green, hut r e d , brown and blue types a l s o occur. are p r e v a i l i n g l y porphyrl t i c , w i t h f e l d s p u r c r y s t a l s 1/8  They inch  or more i n l e n g t h , i n an a p h e n i t i c ground eass. The o l d e r v o l c a n i c s extend as a b e l t from Peninsula Mt. on the shores of Taku Arm to Table Fountain.,  opposite  Taku Landing on Graham I n l e t . i t f i r s t they were subdivided by Cairnes i n t o the P e r k i n s group, and C h i e f t a i n H i l l group, but l a t e r ( i n  1915}  t h i s s u b d i v i s i o n was dropped, and the r o o k s were c o r r e l a t e d w i t h the o l d e r v o l c a n i c s o f White River d i s t r i c t . P o r t i o n s of the o l d e r v o l c a n i c s are d e f i n i t e l y i n t r u s i v e i n t o the Laberge beds, and may  therefore be  considered  younger. C o c k f i e i d considers them to be Lower or I'iddle Jurassic.  Cairnes,, D. D.  ^Upper White R i v e r D i s t r i c t ,  G. S.. £. Kern. 50, p. 87-93.  C a i r n e s , D. D. G.S.c. Sum.  Rept.  1915.  111. Coast Range I n t r u s i v e s . The w e s t e r n p o r t i o n o f t h e d i s t r i c t i s o c c u p i e d by the C o a s t Range i n t r u s i v e s .  B e s i d e s the l a r g e r a r e a s a number o f  s m a l l e r exposures o c c u r i n v a r i o u s l o c a l i t i e s through t h e d i s trict.  A p p a r e n t l y a l l t h e s e g r a n i t i c masses are a p a r t o f the  same Coast Range B a t h o l i t h . The Coast Range i n t r u s i v e s a r e f o r t h e most p a r t f r e s h and u n a l t e r e d i n appearance, a r e p r e d o m i n a n t l y g r e y i s h i n c o l o u r , and have t h e g e n e r a l appearance o f t y p i c a l , medium to coarsely textured granites* The o r t h o c l a s e i s l o c a l l y s u f f i c i e n t l y prominent t o g i v e these r o c k s a p i n k i s h c o l o u r , but t h i s i s e x c e p t i o n a l .  In  p l a c e s t h e s e i n t r u s i v e s become p o r p h y r i t i c i n s t r u c t u r e and c o n t a i n numerous l a r g e f e l s p a r p h e n o e r y s t s as much as l£ t o 2 inches i n l e n g t h . Another type i s much f i n e r g r a i n e d , and c o n t a i n s no quartz, approaching true d i o r i t e i n composition.  Hornblende,  b i o t i t e and a u g l t e a r e g e n e r a l l y p r e s e n t and ore i n most c a s e s r e a d i l y v i s i b l e to the u n a i d e d eye. As found by l a t t e r work o f D. D. C a i r n e s and 1 . d. C o c k f i e i d the i n t r u s i v e s c u t Laberge  s e r i e s and even T a n t a l u s  conglomerate. C a i r n e s a t f i r s t ma  m i s l e a d by the f a c t t h a t t h e  Laberge beds c o n t a i n d i o r i t i c p e b b l e s s i m i l a r t o the Coast Range B a t h o l i t h m a t e r i a l , but s i n c e r o c k s o f lower P a l a e o z o i c age c o n t a i n i n g d i o r i t i c p e b b l e s have been found on the A l a s k a n  112.  c o a s t , t h i s i s no l o n g e r an argument t o suppose that t h e B a t h o l i t h was i n t r u d e d i n p r e Laoerge t i m e .  I t i s much s a f e r ,  c o n c l u d e s C o c k f i e l d , t o c o n s i d e r t h e C o a s t Range i n t r u s i v e s w i t h r e s p e c t only  to th© r o c k s w h i c h t h e y c u t .  From t h i s i t seems t h a t t h e i n t r u s i v e s a r e n o t e a r l i e r than t h e l o w e r p a r t o f the m i d d l e J u r a s s i c .  The B a t h o l i t h may  be r e g a r d e d a s Upper J u r a s s i c o r l a t e r .  Hewer V o l c a n i c a. S m a l l a r e a s n e a r the town o f A t l i n , i n t h e v a l l e y s o f Ruby Creek and other c r e e k s d r a i n i n g i n t o S u r p r i s e L a k e , and f a r t h e r n o r t h i n t h e v a l l e y o f S i l v e r Creek a r e covered w i t h very recent l a v a s . The  Some o f t h e s e o v e r l i e g o l d bearing; g r a v e l s .  l a v a s a r e T e r t i a r y and quaternary  In general  i n age.  the v o l c a n i c a c t i o n must have been very  r e c e n t , as hot s p r i n g s and m i n e r a l s p r i n g s a r e found i n s e v e r a l p l a c e s i n the v i c i n i t y o f A t l i n .  These e v i d e n t l y i n d i c a t e  after volcanic action. Recent S e d i m e n t s . Those a r e m o s t l y found i n the v a l l e y s , and a r e made o f coarse  sands o f g r a n i t i c o r i g i n , and g r a v e l s o f g l a c i a l end  post g l a c i a l o r i g i n .  I n the v a l l e y s o f some o f the c r e e k s the  g r a v e l s a r e u n d e r l a i n by "hard pan" made o f f a i r l y w e l l c o n s o l i dated t i l l i t e .  I n p l a e e s t i l l i t e o v e r l i e s o l d e r g r a v e l s wh i c h  are a l s o sometimes g o l d b e a r i n g .  The g r a v e l s i n P i n e Creek  V a l l e y c o v e r t h e p e r i d o t i t e s and p y r o x e n i t e s o f the g o l d series.  113  Keqnomlc Geology*  Atlin  District.  For q u i t e a w h i l e a f t e r i t s e s t a b l i s h m e n t gold producing  i n 1896  as a  camp, A t l i n d i d not pay much a t t e n t i o n to any-  thing but placer gold deposits,  but i t i s easy to change from  p l a c e r g o l d p r o s p e c t i n g and s t a r t l o o k i n g f o r the o r i g i n o f m e t a l , and  so t u r n to q u a r t z  P r o s p e c t i n g and  prospecting.  g e o l o g i c a l work done i n the  by P r o f . G w i l l l r a i n 1901,  the  district  have shown t h a t the d i s t r i c t i s  u n u s u a l l y f a v o u r a b l y l o c a t e d , f o r o c c u r r e n c e s o f ore S e v e r a l t^pea o f d e p o s i t s a r e f o u n d , and are  deposits. classified  by D. D. C a i r n e s i n G. S. C. fiemoir 37 as f o l l o w s ; Ore  Deposits,  (a) G o l d - t e l l u r i u m q u a r t z v e i n s . {b)  G o l d - s i l v e r veins  (c) Cupriferous s i l v e r gold  veins  (d) s i l v e r l e a d v e i n s (e) copper v e i n s ( f} antimony veins. (g)  c o n t a c t metamorphic d e p o s i t s . I t 13 c l e a r l y s e e n from the l i s t ,  t h a t to produce such  a d i f f e r e n c e i n types o f ore d e p o s i t s , e o n s i d e r a o l e d i f f e r e n c e i n g e o l o g i c a l c o n d i t i o n s must e x i s t .  This i s q u i t e time, and  tne A t l i n D i s t r i c t l a very r i c h i n d e e d , i n examples o f v a r i o u s s t r u c t u r e s and  rocks.  tie have the e f f e c t of the Coast Range B a t h o l i t h , the  114. smaller s a t e l l i t i c  b a t h o l i t h s , and  s e d i m e n t a r l e s and v o l c a n i c s . v a r i e t y o f c h e m i c a l and  the v a r y i n g i n f l u e n c e s o f  I t i a therefore clear that a  p h y s i c a l c o n d i t i o n s was  available for  the f o r m a t i o n o f these d i f f e r e n t types o f d e p o s i t s . I t seems a l m o s t i m p o s s i b l e to g e n e r a l i z e f o r tne t r i c t as a w h o l e , except may to and  dis-  be, t h a t m a j o r i t y o f d e p o s i t s seem  be c o n n e c t e d .vith tne i n t r u s i o n o f the Ooaat Hange B a t h o l i t h , the s m a l l e r B a t h o l i t h s i n the P l a t e a u r e g i o n .  B a t h o l i t h s may  o r may  The  not be o f the same age as the Main Batho-  l i t h , although C o c k f i e l d s t a t e s that l i t n o l o g i c a l l y l i t h s are s i m i l a r , and a r e o f the same In  smaller  the Batho-  that t h e r e f o r e i t i s probable  t h a t they  age.  d e s c r i b i n g t h e d e p o s i t s o f the D i s t r i c t I i n t e n d to  f o l l o w i n g e n e r a l way  C a i r n e ' s p l a n , I . e . , d e s c r i b e them by  t y p e s , but a d d i n g new  i n f o r m a t i o n , added s i n c e C a i r n e s  w r i t t e n h i s r e p o r t on the D i s t r i c t . p a r t i c u l a r l y to the E n g i n e e r  has  These changes w i l l  Gold B i n e s , and  the  ttlin  apply Huffner  M i n e , s i n c e these p r o p e r t i e s r e c e i v e d c o n s i d e r a b l e amount o f a t t e n t i o n d u r i n g the l a s t y e a r s , w h i l e very l i t t l e  work  was  done on the r e s t . One  n o t a b l e e x c e p t i o n among the m i n e r a l d e p o s i t s o f  A t l i n D i s t r i c t i s the a t l i n H u f f n e r M i n e . d e f i n i t e l y post J u r a s s i c , and  This deposit i s  p o s s i b l y T e r t i a r y i n age.  More d e t a i l e d d e s c r i p t i o n of tne p r o p e r t y w i l l  be  found f a r t h e r down, but i t might be .i/ell to s t a t e the g e n e r a l r e a s o n s f o r p l a c i n g the f o r m a t i o n o f tne d e p o s i t as Jurassic.  Post  XX 5 •  fhe c o u n t r y r o c k , I s the t y p i c a l q u a r t z d i o r i t e g r a n o d l o r i t e o f J u r a s s i c age.  T h i s g r a n o d i o r i t e was  by e o r a p r e s s i o n a l s t r e s s e s , a p p a r e n t l y a c t i n g d u r i n g Laramide R e v o l u t i o n .  The f i s s u r e s  Lamprophyre and q u a r t z p o r p h y r y ,  or  fissured the  ;ere t h e n T i l l e d >;Ith ^ f t e r c o n s o l i d a t i o n these  dykes were f i s s u r e d a g a i n , and m i n e r a l i z e d .  This m i n e r a l i z i n g  p e r i o d c o u l d h<.ve o c c u r r e d o n l y a f t e r Laramide r e v o l u t i o n , i . e . during T e r t i a r y .  116.  Atlin District.  _o.  Geology.  General. fype o f D e p o s i t *  Occurrence. Juras8io  Gold T e l l u r i u m E n g i n e e r Mine.  Laberge  series,  a r g i l l i t e s , grey-  Age?  lineral  association.  Jurassic  Quartz,calcite,  batholith  marlposite gold  Gold S i l v e r V e i n  waeke^s i n hornblende  Quartz,calcite,  Happy S u l l i v a n  diorlte  galena,pyrite chaleopyrite  Cupriferous  i n Andesite of  S i l v e r Gold V e i n s  Jurassic  Jurassic  .^uartz, c a l c i t e , galena, chaleo-  ->ge.  pyrite .pyrite,  The P e t t y Group  malachite. S i l v e r Lead Veins.  qptz,calcite,  Dykes i n q u a r t z  Post Jur-  Diorite  a s s i c , pos- g a l e n a , a p h a l e r -  A t l i n E u f f n e r Mine  and  Diorite  s i b l y Ter- i t e , p y r i t e , tiary  pyrrhotite,arsenopyri te , ruby  Copper V e i n s  Olivine  basalts  Jurassic  silver  calcite,native copper ,iaalachi t e , c upri te.  Antimony V e i n s  Shales o f La-  Probably  quartz,stibnite,  berge  Jurassic Jurassic  galena.  series.  C o n t a c t Meta-  I.;t.  morphic  Pre Cambrian  sits.  Depo-  Stevens  magnetite,hemat i t e .chaleopyrite tetrahedrite, erythrite.yellow garnet,faiotite.  117. GoId-Tellurium  Velna.  General. G o l d - t e l l u r i u m q u a r t z v e i n s have been d i s c o v e r e d i n A t l i n d i s t r i c t i n o n l y one l o c a l i t y w h i c h i s s i t u a t e d on the e a s t s i d e o f Taku arm. above Golden Gate. o f the v e i n s o c c u r a t the E n g i n e e r  The g r e a t e r number  mines where the b u l k o f the  r i c h o r e i n t h i s t y p e o f d e p o s i t s have been found.  Veins  ' c o n t a i n i n g pockets o f good o r e , however, have a l s o been d i s c o v e r e d on the a d j o i n i n g c l a i m s .  The Engineer # taken f r o m . c o n f i d e n t i a l Dr. ./. E. C o c k f i e i d .  Mines.  r e p o r t t o the Mine Manager by  The a u t h o r v i s i t e d the mine and  recheoked a l l the o b s e r v a t i o n s a y e a r  later.  118. f h e E n g i n e e r M i n e.  by tf. S. C o c k f i e i d .  f h e E n g i n e e r Mine i s s i t u a t e d on f a g i s h L<«;e, a p p r o x i m a t e l y 12 m i l e s south o f G o l d e n G a t e , where t h e r o u t e t o A t l i n t u r n s t o the e a s t .  T h i s p r o p e r t y has been known f o r a l o n g  time and has f r e q u e n t l y aroused  i n t e r e s t on account  ofi t s  s p e c t a c u l a r g o l d showings. f h e r e h a s , however, been c o m p a r a t i v e l y l i t t l e w r i t t e n w i t h r e g a r d to t h e geology The  o f the property i n recent y e a r s .  e a r l i e r developments a r e d e s c r i b e d by C a i r n e s  and des-  c r i p t i o n s o f t h e p r o p e r t y have a l s o been g i v e n i n t h e annual r e p o r t s o f t h e 3. 0. M i n i s t e r o f M i n e s ,  a few y e a r s ago the  f i r s t attempt was made t o mine t h i s p r o p e r t y on a l a r g e s c a l e and  a g r e a t d e a l o f money aas spent on the development o f t h e  mine and I n Improvements t o tne'eamp, but the v e i n s c o n t a i n i n g the h i g h  trade o r e d i d n o t f u r n i s h s u f f i c i e n t tonnage t o J u s -  t i f y o p e r a t i o n s on t h e s c a l e on which they were attempted and the v e n t u r e ended i n f a i l u r e . been w o r k i n g  S i n c e t h a t time a s m a l l crew has  to explore c e r t a i n p o s s i b i l i t i e s o f developing a  l a r g e tonnage o f low grade o r e which nas been i n d i c a t e d by some o f the development c a r r i e d out on the h i g h grade v e i n s ,  lately  the p r o p e r t y has been c l o s e d down due t o f i n a n c i a l t r o u b l e s , but i t i s a n t i c i p a t e d t h a t i t w i l l  be re-opened a t an e a r l y  The c o u n t r y r o c k i n the v i c i n i t y o f the E n g i n e e r consists of Jurassic a r g l l l i t e s ,  C a i r n e s , D. D.  date  Line  greywaekes, e t c . , b e l o n g i n g to  G e o l . S u r v . Canada, kern. 37, p. 73 - 89.  119.  the Laberge s e r i e s .  These a r e p i e r c e d some d i s t a n c e back o f  the p r o p e r t y by a s t o c k o f g r a n o d i o r i t e w h i c h forms Mt.  Engineer  On the p r o p e r t y i t s e l f and towards I t s s o u t h e r n  end a r e  two s m a l l o u t c r o p s o f g r a n o d i o r i t e , a p p a r e n t l y p a r t o f t n e same s t o c k which has been b a r e l y  deroofed.  The v e i n s y s t e m i a i n t r i c a t e and i t I s l a r g e l y  because  o f t h e amount o f development work which has been done by E n g i n e e r M i n e s L t d . t h a t t h e r e l a t i o n s show as c l e a r l y as they d o . In  th® c e n t r a l p a r t o f t h e p r o p e r t y a r e two Hubs o f q u a r t z ;  one o f t h e s e b e i n g s i t u a t e d 200 f t . e a s t from the s h o r e . o f the l a k e , and t h e o t h e r about 1,400 f t . e a s t o f t h e f i r s t . a r e known as Hubs "A" and "B" r e s p e c t i v e l y . l a r g e r o f t h e two and I s a p p r o x i m a t e l y  These  Hub "A" i s the  £40 f t . l o n g by 160 f t .  w i d e , and i s composed o f a number o f v e i n s o f q u a r t z o f c o u n t r y r o c k and i n c l u d e d c o u n t r y r o c k ; t h e whole f o r m i n g a Hub "B" i s a p p r o x i m a t e l y i n c h a r a c t e r to Hub ",«.".  stockwork.  120 x 80 f t . , and i s s i m i l a r  There zones h.ve been e x t e n s i v e l y  t e s t e d , b u t so f a r have not been proved  t o c a r r y commercial  values. There a r e a l s o a number o f v e i n s w h i c h were o r i g i n a l l y thought  t o r a d i a t e o u t from t n e s e nubs but more r e c e n t work  tends t o throw some doubt on t h i s t h e o r y .  The p r i n c i p a l v e i n s  a r e t n e Double Decker, E n g i n e e r , J e r s e y L i l y , B o u l d e r , and  Blue v e i n s .  uidy,  I n a d d i t i o n there are a uur.iber o f o t h e r s whloh  have been more o r l e s s n e g l e c t e d i n the r e c e n t developments. Running from t n e g r a n o d i o r i t e o u t c r o p s near tne s o u t h end o f t h e p r o p e r t y towards Hub " a " , t n e r e i s a shear zone waioh i s marked on t h e s u r f a c e by a pronounced t o p o g r ^ p u i c  depression  120. and w h i c h l a w e l l shown i n the underground w o r k i n g s .  Instead  o f t h e w i n s r a d i a t i n g out from the Hubs o f q u a r t z p r e v i o u s l y mentioned. I t would appear t h a t they a r e connected w i t h  this  zone o f s h e a r i n g from w h i c h they appear to be g i v e n o f f a t d i f ferent angles.  T h i s shear zone d i v i d e s the v e i n s i n t o  g r o u p s — - t h e Double Decker, E n g i n e e r t o the w e s t , and  and J e r s e y L i l y v e i n s l y i n g  the b o u l d e r , Andy and  e a s t o f t h i s zone.  two  Blue v e i n s l y i n g to  tne  I t s r e l a t i o n t o the v e i n s i s not q u i t e  a p p a r e n t ; none o f t h e v e i n s have been t r a c e d i n t o the s h e a r o r across I t .  They a l l a p p a r e n t l y s t a r t a s h o r t d i s t a n c e f r o m  t h i s zone. There are two s e t s o f dykes on the p r o p e r t y . these i s r o u g h l y and  of  p a r a l l e l t o the d i r e c t i o n o f the shear zone  the o t h e r r o u g h l y p a r a l l e l t o the E n g i n e e r  veins.  One  and Double Decker  These dykes a r e b e l i e v e d to be s a t e l l i t i c to the  gran-  i t e and the two s e t s are b e l i e v e d to be e s s e n t i a l l y contemporaneous.  On account o f the l a c k o f o u t c r o p s  near t n e i r p o i n t s o f  i n t e r s e c t i o n t h i s c o u l d not be d e f i n i t e l y d e t e r m i n e d but n e i t h e r s e t o f dykes a p p a r e n t l y o f f s e t s the o t h e r . are o l d e r t h a n the v e i n system.  B o t h s e t z o f dykes  T h i s i s e a s i l y seen from the  underground w o r k i n g s where the dykes are c u t and o f f s e t by veins.  the  I n p l a c e s the dykes a r e h e a v i l y impregnated w i t h p y r i t e . The  v e i n s are c h a r a c t e r i s t i c a l l y narrow and range from  mere s t r i n g e r s up t o two f e e t o r more i n t h i c k n e s s .  The  better  ©ineralized p a r t s o f the v e i n s are i n many c a s e s o n l y 6" to 8" thick.  Most o f the v e i n s a r e f i l l e d w i t h q u a r t z .  The  Engineer  v e i n , however, has a o a l c l t e - m a r i p o a i t e f i l l i n g . The  w o r k i n g s above the f i f t h l e v e l are l a r g e l y  stoped  121. out and  were not v i s i t e d .  The  main w o r k i n g s at the  present  t i m e c o n s i s t o f t h e f i f t h , s i x t h , s e v e n t h and e i g h t h l e v e l s . The  f i f t h l e v e l forms the main e n t r y to the mine.  T h i s l e v e l has been d r i v e n from a p o i n t somewhat o v e r 100 above the l a k e l e v e l , and was 1450 625  feet long.  feet  a t the time o f the w r i t e r s v i s i t f  T h i s a d i t e n c o u n t e r s the Double Decker  f t . , and t h e E n g i n e e r V e i n a t 1185  t i n u e d to i n t e r s e c t the s h e a r zone.  f t . and  was  vein,at  being  con-  From the p o i n t where the  a d i t e n c o u n t e r s the Double Decker v e i n , a d r i f t has been r u n t h i s v e i n 640  f t . i n southwesterly  n o r t h e a s t e r l y d i r e c t i o n , and c r o s s c u t t h e s h e a r zone.  d i r e c t i o n and 360  i s continued  on  feet i n a  i n t h i s d i r e c t i o n to  Throughout t h i s d i s t a n c e the  vein  v a r i e s from a narrow s t r i n g e r to about Z f e e t , and c o n s i s t s o f quartz c a r r y i n g values i n free gold. v a l u e s are encountered-. and  e r e v i c e s i n the The  The g o l d a p p a r e n t l y  spectacular  follows cracks  quartz.  E n g i n e e r V e i n has  west fro® the a d i t and Is continued  Occasional  E£0  been d r i f t e d on 1100  feet northeast.  This l a t t e r  as a c r o s s c u t t h r o u g h the J e r s e y L i l y  s h e a r z o n e , and  f e e t southdrift  v e i n , the  to the iindy, B o u l d e r and Blue v e i n s w i t h a  c o n s i d e r a b l e t o t a l o f d r i f t i n g on the l a t t e r t h r e e v e i n s . the southwest d r i f t a s h a f t has  been sunk to the 800  w i t h i n t e r m e d i a t e l e v e l s a t 600  and 700  The two  feet.  foot l e v e l  feet.  E n g i n e e r V e i n ranges i n w i d t h  from a seam t o n e a r l y  I t d i f f e r s from the o t h e r v e i n s o f tne p r o p e r t y  being m i n e r a l i z e d w i t h c a l c i t e , mariposite  free gold.  The  in  (chrome micaft  a l l e m o n t i t e ( a compound o f n a t i v e a r s e n i c and and  From  n a t i v e antimony)  g o l d I s a s s o c i a t e d w i t h the m a r i p o s i t e .  122. fhe B o u l d e r v e i n where c u t by the 500 4 f e e t wide and has been d r i f t e d on f o r 600  foot l e v e l i s  f t . It  maintains  t h i s width over a considerable part of t h i s d i s t a n c e . s i s t s o f q u a r t z , w i t h i n c l u d e d fragments o f c o u n t r y c a r r i e s In spots high values i n g o l d . o f t h e f a u l t zone and  I t con-  rock  and  I t l i e s on e a s t e r n s i d e  t r o n d s away from i t a t an angle  of  30 d e g r e e s . The  Andy and B l u e v e i n s a r e somewhat s i m i l a r to Double  Decker v e i n . o f 400  The l a t t e r has an i n d i c a t e d l e n g t h on the s u r f a c e  f t . , but was  not v i s i t e d i n the underground .workings  owing t o v e n t i l a t i o n d i f f i c u l t i e s .  These v e i n s do n o t , so f a r  as i s known, c o n t a i n t h e s p e c t a c u l a r v a l u e s found i n some o f th©  other veins. The J e r s e y L i l y v e i n from s u r f a c e and  underground  w o r k i n g s has an I n d i c a t e d l e n g t h o f 1400  f t . but i t has not been  t r a c e d c o n t i n u o u s l y over t n i s d i s t a n c e . o  I t i s inclined  f a u l t zone a t 30  towards the southwest.  to  the  I t a l s o does n o t ,  so  f a r as known, c o n t a i n s p e c t a c u l a r v a l u e s i n g o l d . The  w o r k i n g s below the 500 l e v e l are f u l l o f water  consequently  c o u l d not be examined.  The  and  following information,  however, k i n d l y made a v a i l a b l e by Mr. Hershman, g i v e s an  out-  l i n e o f the work done. On the 600 l e v e l the E n g i n e e r f o r 160  f t . S.i/. from the s h a f t and  shaft.  On  on f o r 260 800  the 700  V e i n has  f t . S.tf. from the s h a f t and 320  f t . II.fi.  been d r i f t e d On  V e i n has been d r i f t e d on 320  from the s h a f t and f o r 280  on  f o r 80 f t . Ji.E. from the  f o o t l e v e l the E n g i n e e r  f o o t l e v e l the E n g i n e e r  S. W.  v e i n has been d r i f t e d  f t . northeast  the feet  from the s h a f t .  123. I n t h e s e w o r k i n g s t h i s v e i n shows e s s e n t i a l l y tne same c h a r a c teristics  as t o w i d t h and m i n e r a l i z a t i o n as i n t h e upper l e v e l s .  On t h e 800 f o o t l e v e l t h e r e i s a c r o s s c u t 380 f t . l o n g to  t h e Double Decker v e i n w i t h a d r i f t on the l a t t e r 400 f t *  l o n g ; the g r e a t e r part o f t h i s d i s t a n c e l y i n g t o the northeast of  the c r o s s c u t .  The Double Decker v e i n shows a d e f i n i t e  w i d e n i n g on. t h e 800 l e v e l where i t has an average w i d t h o f Z f e e t and a maximum o f a b o u t f o u r f e e t . until  This d r i f t  continues  i t c u t s t h e s h e a r zone and from i t t h e s h e a r zone has  been d r i f t e d on f o r 330 f t . t o the n o r t h w e s t and f o r 500 f t . to  the s o u t h e a s t , t h e d r i f t b e i n g o n l y p a r t l y i n the s h e a r zone  and l a r g e l y i n the dyke w h i c h accompanies i t * The s h e a r zone I s one o f t h e most i m p o r t a n t f e a t u r e s o f the  property,  AS i n d i c a t e d by t h e topography i t i s q u i t e p e r -  s i s t e n t and underground i t has been opened a t s e v e r a l p o i n t s . On t h e 500 f o o t l e v e l i t i s c r o s s e d by t h e Double Decker and Engineer d r i f t s At  and on t h e 800 l e v e l by t h e Doable Decker d r i f t .  each p o i n t where c u t by t h e underground w o r k i n g s i t i s w e l l  m i n e r a l i z e d w i t h q u a r t z h e a v i l y impregnated w i t h p y r i t e and c a r r i e s values i n g o l d .  The w i d t h o f t h i s zone v a r i e s ; but  I n c l u d i n g t h e d y k e , w h i c h i n many oases accompanies I t , I s as much as 65 f e e t w i d e .  Of t h i s 20 t o 28 f e e t i s w e l l m i n e r a l -  i z e d w i t h q u a r t z and p y r i t e .  Good v a l u e s have been i n d i c a t e d  o v e r w i d t h s o f 6 t o 14 f e e t w i t h l o w e r v a l u e s o v e r t h e whole zone.  124* f h e p r o p e r t y has may  i n t e r e s t i n g p o s s i b i l i t i e s , while i t  he d e f i n i t e l y s t a t e d t h a t there i s not s u f f i c i e n t ore i n the  v e i n system t o m a i n t a i n a l a r g e o p e r a t i o n , y e t t h e r e i s s u f f i c i e n t to p e r m i t the p r o p e r t y t o be worked I n a s m a l l way. d e f i n i t e widening and  the w i d e n i n g  t h a t t h e r e may  o f the Double Decker v e i n on the 800 o f the B o u l d e r v e i n on the 500  The level  level indicate  be a p o s s i b i l i t y o f the v e i n s I n c r e a s i n g I n  width with depth.  The  i n c r e a s e i n w i d t h so noted have not been  accompanied by a d e f i n i t e t r e n d toward l o w e r v a l u e s . the Doable Decker and E n g i n e e r t h i s a l t i t u d e be c o n t i n u e d  Further  v e i n s a r e I n c l i n e d so t h a t i f '  they wi11 I n t e r s e c t .  The most i n t e r e s t i n g p o s s i b i l i t y , however, i s the chance t h a t w i t h i n the shear zone a c o n c e n t r a t i o n o f workable grade and w i d t h o f ore w i l l be e n c o u n t e r e d , s h e a r zone ha3 not been e x p l o r e d . o f about 4000 f e e t and may zone was  A l a r g e part of t h i s  I t has an i n d i c a t e d l e n g t h  be much l o n g e r and as t h i s  l i k e l y the main c i r c u l a t i n g c h a n n e l  shear  f o r the m i n e r a l i z -  i n g s o l u t i o n s t h e r e i s a p o s s i b i l i t y o f c o n c e n t r a t i o n s o f ore a l o n g I t which might s u p p l y the necessary property a success. a g i n g and  tonnage to make the  The v a l u e s i n d i c a t e d i n p l a c e s are encour-  f u r t h e r work on t h i s zone i s j u s t i f i e d by the  results  already obtained. Any  f u r t h e r work which I s done on t h i s p r o p e r t y  be watched w i t h i n t e r e s t f o r i t i s u n l i k e l y t h a t s u c h zones would o c c u r s i n g l y .  will  shear  As t h e r e are s e v e r a l p r o p e r t i e s i n  the v i c i n i t y which e x a i b i t seams o f h i g h grade g o l d o r e s , t h e r e i s a p o s s i b i l i t y t h a t these o c c u r i n c o n n e c t i o n w i t h s i m i l a r zones o f s h e a r i n g .  I f the zone on the E n g i n e e r can be proved to c u r r y o r e b o d i e s o f commercial s i z e and grade much more work would be J u s t i f i e d on these o u t l y i n g d e p o s i t s t h a n has been the case i n the past.  126. Gold-Silver Type. S e v e r a l ore deposits i a the d i s t r i c t belong t o t h i s type, a n d have been found a t a number o f p o i n t s , the most imp o r t a n t o f whieh a r e ; White Moose, Rupert and Happy  Sullivan  g r o u p s on the Taku arm* the Lawson group on B i g h o r n C r e e k ; a t the B e a v l s M i r e n e a r the Town of A t l i n ; - the I m p e r i a l l i n e on Munrae M o u n t a i n e a s t o f A t l i n ; and on the B r o t h o n and A l v l n e c l a i m s on Haboe Creek n e a r the Lead o f T o r r e s C h a n n e l , an arm of A t l i n Lake. Generally  these v e i n s cons i t m a i n l y  o f quartz, but  some a l s o c o n t a i n c a l c i t e a s an a s s o c i a t e d gangue m i n e r a l . Galena and p y r i t e a r e the most common m e t a l l i c m i n e r a l s b u t i n a d d i t i o n C h a l e o p y r i t e and T e t r a h e d r i t e f r e q u e n t l y o c c u r , and n a t i v e g o l d and n a t i v e s i l v e r r r e o c c a s i o n a l l y found.  The  ores a r e g e n e r a l l y o f v a l u e mainly f o r t h e i r g o l d content, but they always c o n t a i n more o r l e s s s i l v e r w h i c h i n p l a c e s even exceeds g o l d i n v a l u e . The I m p e r i a l Mines.f~ The I m p e r i a l Mines a r e l o c a t e d on t h e Munro M o u n t a i n , some 5 m i l e s from t h e town o f A t l i n .  A good a u t o m o b i l e road i s  f o l l o w e d f o r 4 m i l e s t o H a l f - w a y Rouse on P i n e C r e e k , and from there a t r a i l  t o the f o o t o f Munro M o u n t a i n .  The a u t h o r  visit-  ed t h e mine i n 1931, b u t a s t h e w o r k i n g s were h a l f caved i n no # Robertson,W.F., R e p o r t o f t h e M i n i s t e r o f I'ines, B.C. 1900-04. Gwilliffi,J.C. C a i r n e s , D. D.  "Report on the A t l i n Mining D i s t r i c t , E . G . * G.S.C, G.S.C. Mem, Ho. 37.  127. attempt was made t e examine them i n d e t a i l ,  large quantities  of milky white quartz were noted on the dump.  D. D. Ceirnes  describes the mine as f o l l o w s : *-—The entrance t o the lower tunnel i s 1030 f e e t i n e l e v a t i o n above A t l i n whsrf  — "  " A l l work a t these mines has been expended i n developi n g a s i n g l e quartz lode which occurs i n a f i n e l y - t e x t u r e d rock that ranges from hornblende-diorlte porphyrite. •n  50  to a hornblende-diorite  The lode s t r i k e s H. 70° E* and dips e t angles of  O  t o 60  to the southeast.  This deposit includes two o r three c l o s e , p a r a l l e l , m i n e r a l i z e d f i s s u r e s which contain an aggregate thickness o f £ to 3 f e e t o f v e i n m a t e r i a l c o n s i s t i n g mainly o f q u a r t z , sparsely d i s t r i b u t e d through which are p a r t i c l e s o f galena*, c h a l e o p y r i t e , p y r i t e , malachite, and o c c a s i o n a l l y , native g o l d . A considerable p o r t i o n o f the quartz i s thought to contain from £10 to $30 per ton i n gold and s i l v e r , the s i l v e r being r e l a t i v e l y small i n amount.  Two cross-cut tunneIs have been  d r i v e n , which tapped the v e i n a t 25 and 112 f e e t r e s p e c t i v e l y , and from these over 400 f e e t of u r i f i s have been d r i v e n . The formation  at the Imperial Mines appears to be  c h i e f l y a dark greenish to brownish green, dense, f i n e l y text u r e d , rock that i s e i t h e r megascopically  e n t i r e l y a p h a n i t i c or  contains v i s i b l e hornblende phenocrysts i n an a p h a n i t i c groundmass, and ranges from a hornblende d i o r i t e t o a hornblended i o r i t e porphyrite.  Under the microscope a t y p i c a l sample  v 128. p r o v e d t o be composed l a r g e l y o f p l a g l o c l a a e and pale b r o w n i s h h o r n b l e n d e , w i t h some a c c e s s o r y  i r o n o r e , the hornblende  r i n g i n s h r e d s and I r r e g u l a r p r i s m a t i c forms I m p e r f e c t l y minated and c o n s t i t u t i n g n e a r l y h a l f of the r o c k  occurter-  mass.  Be s c r i p t i o n o f V e i n s . — A l l the work on t h e s e c l a i m s has been expended i n d e v e l o p i n g one main v e i n o r l o d e w h i c h s t r i k e s o o o a p p r o x i m a t e l y 1. 70 11., d i p s from 50 t o 60 t o t h e S.S., c o n t a i n s where i t has been e x p o s e d , f r o m 1 t o 7 f e e t o f v e i n m a t e r i a l , and has been t r a c e d f o r a d i s t a n c e o f over 500 f e e t . The v e i n i s n o t s i m p l e  i n form but i n c l u d e s , i n moat p l a c e s ,  the q u a r t z and a s s o c i a t e d m i n e r a l s  which have been d e p o s i t e d i n  s e v e r a l oloue p a r a l l e l f i s s u r e s , and have a l s o r e p l a c e d more o r l e s s o f the o r i g i n a l intervening w a l l rock.  The v e i n i s thus  a compound v e i n , o r s i n c e r e p l a c e m e n t has been e f f e c t i v e t o a considerable  degree i n a l t e r i n g  the i n t e r v e n i n g ; and I n t e r c a l -  a t e d rock p o r t i o n s , the term l o d e i s p r o b a b l y most  appropriate.  On account o'f i t s compound n a t u r e t h i s v e i n n a t u r a l l y varies considerably  i n t h i c k n e s s and i s a l s o i r r e g u l a r i n  s t r i k e and d i p . The main m i n e r a l i z e d f a u l t zone which c o n s t i t u t e s t h i s l o d e i s f a i r l y p e r s i s t e n t ; but t h e v a r i o u s  small  i n c l u d e d members a r e q u i t e e r r a t i c and i n most p l a c e s t h e l o d e i s d i v i s i b l e i n t o two o r more d i s t i n e t p a r t s . The v e i n m a t e r i a l appears t o have an average  thickness  of from 2 t o 3 f e e t and c o n s i s t s m a i n l y of q u a r t z which i s o f t e n i r o n s t a i n e d o r rose c o l o u r e d , and f r e q u e n t l y e x h i b i t s  k  129.  t r u s t i f i c a t i o n and comb s t r u c t u r e s , but i s a l s o i n places quite massive i n appearance.  Sparsely d i s t r i b u t e d through the quartz are p a r t i c l e s of galena, c h a l c o p y r i t e ,  p y r i t e , malachite and f r e e g o l d .  Pockets o r shoots o c c u r , however, i n which these  metallic  minerals occur p l e n t i f u l l y . " The contact o f the i n t r u s i v e b a t h o l i t h , i s only a short d i s t a n c e back o f the mine i n a northern d i r e c t i o n .  Another Gold s i l v e r  p r o p e r t y i s the Happy Sullivan  Mine.  M i n i s t e r o f Mines Report, 1930.  130. M i n i s t e r o f Mines R e p o r t ,  1930.  Eappy S u l l i v a n I'lne.  G o l d - S i l v e r Type. T h i s p r o p e r t y , owned by C l a r e n c e Sands and a s s o c i a t e s , of A t l i n I s s i t u a t e d a b o u t 3 m i l e s n o r t h o f the E n g i n e e r about 2 m i l e s from t h e south end o f Taku Arm, The  and  Tagish Lake.  c l a i m s are a t a l t i tude 3700 f e e t on the n o r t h s i d e of  Sheep Creek and about 2 m i l e s f r o m the shore o f the l a k e . The  ore o c c u r r e n c e  i s a l a r g e p y r i t i z e d shear zone  c o n t a i n i n g g o l d v a l u e s i n q u a r t z s t r i n g e r s , o c c u r r i n g i n bedded  sandstone o f the Laberge s e r i e s o f Lower o r K i d d l e  J u r a s s i c age.  S u r f a c e t r e n c h i n g ana a l i m i t e d amount o f  t u n n e l l i n g c a r r i e d out u n d e r f o r m e r o p t i o n e r e not c o n c l u s i v e r e g a r d i n g the p o t e n t i a l i t i e s o f the p r o p e r t y .  131. Atlin District.  Economic Geology.  C a p r i f e r o u s S i l v e r Gold  Veins.  Ge General. The v e i n s c o n s i d e r e d under t h i s h e a d i n g have been found in  A t l i n D i s t r i c t on T a b l e mountain which i s s i t u a t e d on the  n o r t h shore o f Graham I n l e t o p p o s i t e Taku L a n d i n g .  The o n l y  two d e p o s i t s on t h i s mountain t h a t have been a t a l l developed o c c u r on t h e P e t t y and Dundee g r o u p s r e s p e c t i v e l y , and o c c u r i n g r a n i t e - p o r p h y r y w h i c h i s i n t r u s i v e i n C h i e f t a i n H i l l andes i t e s and a n d e s l t i c t u f f s .  The v e i n s c o n s i s t m a i n l y o f q u a r t z ,  o a l e i t e , g a l e n a , c h a l e o p y r i t e , p y r i t e , m a l a c h i t e , and a z u r i t e , w h i c h m i n e r a l s o c c u r a l s o t o some e x t e n t d i s s e m i n a t e d the w a l l rocks. to  through  The P e t t y v e i n where exposed i s from 6 i n c h e s  2 f e e t i n t h i c k n e s s and has been t r a c e d f o r over 100 f e e t ;  the Dundee v e i n has a maximum known t h i c k n e s s o f 2.5 f e e t , but has n o t been f o l l o w e d more t h a n 50 f e e t . The P e t t y Group. The P e t t y group c o n s i s t s o f two c l a i m s w h i c h a r e s i t uated on the s o u t h e a s t e r n c o r n e r o f Table f o u n t a i n , o v e r l o o k i n g Graham I n l e t , and a r e about 3_r m i l e s i n n o r t h - w e s t e r l y d i r e c t i o n from Taku L a n d i n g . The r o c k f o r m a t i o n i n t h i s v i c i n i t y c o n s i s t s m a i n l y o f the C h i e f t a i n H i l l ish  v o l c a n i c a w h i c h a r e here p r e v a i l i n g l y  a n d e s i t e s and a n d e s i t i c t u f f s .  green-  These have been e x t e n s i v e l y  invaded by dykes o f g r a n i t e - p o r p h y r y , b e l o n g i n g to the KJuaha intrusivos. (D. D. C a i r n e s , G.S.C, Mem. 37, p. 1 0 6 ) .  132. Only one main v e i n has been so f a r e x p l o i t e d on t h e P e t t y g r o u p , and t h i s o c c u r s i n t h e ' g r a n i t e - p o r p h y r y , o o H. 30 The  S. and has on average d i p o f about 40  t o the n o r t h w e s t .  v e i n c o n s i s t s mainly o f q u u r t z e u l c i t e , galena,  chaloopy-  7  r i t e , p y r i t e , malachite,  and a z u r i t e , and one s m a l l c a v i t y was  found t o be l i n e d w i t h s m a l l c r y s t a l s o f t h e r a r e linarite  (a basic sulphate The  strikes  o f l e a d and  mineral  copper).  q u a r t z i s g e n e r a l l y r u s t s t a i n e d and o c c u r s a s s o c -  i a t e d w i t h v a r y i n g amounts o f c a l c i t e which i n p l a c e s exceeds q u a r t z  i n amount.  abundant o r e m i n e r a l s  even  G a l e n a aud c h a l e o p y r i t e are tne most  p r e s e n t , and o c c u r i n - a p p r o x i m a t e l y e q u a l  amounts and i n s u f f i c i e n t q u a n t i t y i n p l a c e s t o c o n s t i t u t e t h e g r e a t e r p o r t i o n o f the v e i n - m a t e r i a l .  T h i s v e i n has a t h i c k -  n e s s , a t t h e w i d e s t p o i n t so f a r d i s c o v e r e d , but r a p i d l y d i m i n i s h e s 50 100  o f about 2 f e e t ,  t o 6 inches or l e s s w i t h i n a distance o f  f e e t i n each d i r e c t i o n , and has n o t been f o l l o w e d  f o r over  feet. I t i s p o s s i b l e , however, t h a t f a r t h e r development may  show t h e v e i n to extend a somewhat g r e a t e r d i s t a n c e . i o n , several other mineralized  In addit-  f i s s u r e s o c c u r i n p l a c e s on both  s i d e s o f t h i s main f i s s u r e , and w i t h i n d i s t a n c e s o f 1 to 2 f e e t from each w a l l ; and t h e r o c k between these i s t o some e x t e n t replaced  and impregnated w i t h v a r i o u s o r e - m a t e r i a l s ; so t h a t  a t the main s h a f t t h e o r e might be c o n s i d e r e d  t o have a t o t a l  t h i c k n e s s o f 3 f e e t a t t h e s u r f a c e , but towards t h e bottom o f the s h a f t I t s t h i c k n e s s  I s much l e s s .  The o r e i s c l a i m e d to  c o n t a i n f o u r o r f i v e d o l l a r s p e r t o n i n g o l d , w i t h t h e main  133. T a l l i e s i n s i l v e r and c o p p e r ; bat so few t e s t s have been made, t h a t I t i s u n c e r t a i n what average amounts o f t h e s e m e t a l s the ore  carries."  Th& Dundee group c o n s i s t s o f 2 a d j a c e n t c l a i m s to the P e t t y group and I t s g e o l o g y i s v e r y s i m i l a r to the  above.  134. Atlin  District  S i l v e r Lead V e i n s . As an example o f the s i l v e r l e a d t y p e o f d e p o s i t i n tne A t l i n D i s t r i c t , the A t l i n R u f f n e r K i n e , p r e v i o u s l y known as the A t l i n S i l v e r Lead Mine has been chosen.  The a u t h o r spent two  summers on the p r o p e r t y , and i t was t h e r e f o r e deemed b e s t to i n c o r p o r a t e i n t h i s essay h i s r e p o r t on t h e mine, as p r e s e n t e d to the mine manager. Hut as t h e r e p o r t d e a l s o n l y w i t h tne g e o l o g y o f the mine p r o p e r , a few words have t o be added i n r e g a r d t o l o c a t i o n , and g e n e r a l g e o l o g y . The A t l i n R u f f n e r Mine i s l o c a t e d on Leonard M o u n t a i n , b e t t e r known l o c a l l y as t h e fanghan f o u n t a i n .  S u r f a c e Geology. The Vaughan M o u n t a i n i s one o f a s e r i e s o f p e a k s , comp r i s i n g a range r u n n i n g i n a g e n e r a l II. o r S« d i r e c t i o n .  This  range g r a d u a l l y l o s e 3 h e i g h t towards A t l i n L a k e . The Range i s s e p a r a t e d from o t h e r p a r a l l e l Ranges by the V a l l e y o f 4 t h o f J u l y Creek towards >/. and V a l l e y o f S i l v e r Greek t o the E a s t .  The main p o r t i o n o f the Vaughan o r Leonard  mountain l a made o f c o a r s e q u a r t z - d i o r i t e , the summit from about e l e v . 6000 f t . up o f f i n e - g r a i n e d  diorite.  B o t h the q u a r t z - d i o r i t e and t h e D i o r i t e a r e out by a s e r i e s o f p a r a l l e l lamprophyre dykes and a n o t h e r s e r i e s o f s m a l l e r a p l i t e dykes.  The dykes s t r i k e about Ho. 40 S. and d i p  135. o  0  from 6 5  - 70  S. West.  f h e b a s i c dykes v a r y c o n s i d e r a b l y i n s i z e , from a i n e h e s t o about 40* i n w i d t h .  few  As f a r as i s known they r u n con-  tinuously for a distance of several miles.  The d y k e s ,  espec-  i a l l y the l a r g e r o n e s , can e a s i l y be t r a c e d , because o f abundant f l o a t , f r e q u e n t o u t c r o p s , and t r o u g h s which were formed by u more r a p i d e r o s i o n o f the s o f t e r dyke m a t e r i a l . The  e r o s i o n o f the mountain i n g e n e r a l has been c o n s i d -  e r a b l e , and i t r e p r e s e n t s an o l d and p a r t l y eroded g l a c i a l cirque. The mountain was  step f a u l t e d at a comparatively recent  d a t e , .and i n some p l a c e s v e r y good f a u l t escarpments can observed.  be  T h i s i s t r u e o f nearby c o u n t r y as w e l l , and i s  p r o b a b l y b e s t shown on the n e i g h b o r i n g Steamboat t i n t , wnere the s c a r p s are v e r y w e l l The  preserved.T  s u r f a c e o f the mountain i s covered w i t h a g r e a t  q u a n t i t y o f l o o s e b o u l d e r s , w h i c h h i d e the r o c k T h i s made i t i m p o s s i b l e to determine d i o r i t e - d i o r i t e c o n t a c t , and i t was a r b i t r a r y l i n e , w i t h i n 100*  underneath.  a c c u r a t e l y the q u a r t z o n l y p o s s i b l e to draw an  o f the t r u e c o n t a c t .  136.  The d i s t a n c e by a u t o m o b i l e r o a d from A t l i n i s about 17 m i l e s .  This road  f o l l o w s the v a l l e y o f the 4 t h o f J u l y  Greek, f o l l o w i n g a l t e r n a t e l y i t s o p p o s i t e banks.  (V*. J . O k u l i t c h .  "1931 Geology o f A t l i n R u f f n e r Mine."  r e p o r t o f the Mine G e o l o g i s t . )  137, GEOLOGY. Gene r a 1 Ge o l ogy.  The e x a m i n a t i o n o f the mine, the |100  and 4300 w o r k i n g s , and t h e s u r f a c e g e o l o g y from 4100 I'.X.C. t o beyond the C r a t e r Creek has shown t h a t ; 1)  The c o u n t r y r o c k I s a c o a r s e g r a i n e d hornblende  diorite.  quartz-  T h i s r o c k i s t h e same i n 4100 M.I.C. i n t h e 4300  l e v e l , the 4500 l e v e l , and t h e s u r f s ce from t h e main c r o s s c u t t o beyond C r a t e r C r e e k . The  s i z e o f g r a i n v a r i e s somewhat b u t i s e s s e n t i a l l y  the same t h r o u g h o u t .  The r o c k seems to be composed o f p l a g i o -  c l a s e , H o r n b l e n d e , q u a r t z , and B i o t l t e i n s u b o r d i n a t e q u a n t i ties.  O r t h o c l a s e i f p r e s e n t , c a n not be s e p s r e t e d from t h e  o t h e r f e l s p a r by e x a m i n a t i o n o f hand specimens.  Therefore i t i  p o s s i b l e t h a t the r o c k may be ( i n case o r t h o c l a s e i s p r e s e n t ) a g r a n i t e o r a g r a n o - d i o r i t e . But my o p i n i o n , and i t was supperJed by D r . J . T, ¥andy, t h a t the r o c k i s a q u a r t z - d i o r i t e j  r i c h i n hornblende.  T h i s type o f r o c k i s f a i r l y common i n the  Coast Range b a t h o l i t h . Throughout the c o u n t r y rock a r e p a t c h e s o f d a r k e r and f i n e r g r a i n e d m a t e r i a l r e p r e s e n t i n g t h e more b a s i c phases. A t about 6000 f e e t e l e v a t i o n t h e c o u n t r y r o c k changes from q u a r t z - d i o r i t e t o t r u e hornblende much f i n e r g r a i n e d .  diorite.  This rock i s  I t was i m p o s s i b l e due to g r a v e l and  boulder cover to determine  t h e c o n t a c t e x a c t l y , but c a r e f u l  " i n t e r p o l a t i o n " has narrowed t h e p o s s i b l e c o n t a c t zone t o about 100 f e e t each way.  The c e n t s c t a p p a r e n t l y passes  just  138. above EC S h a f t ana  runs s o u t h w a r d , p a s s e s J u s t below  t u n n e l snd c o n t i n u e s  4M  s o u t h , c r o s s i n g the F o u r t h o f J u l y V a l l e y  somewhere .In the v i c i n i t y o f the F i r s t Canyon o f the Creek. The  o t h e r g r a n i t e r o c k , the t r u e p o r p h y r l t i c g r a n i t e ,  mentioned i n r e p o r t s o f the C a n a d i a n G e o l o g i c a l Survey has  not  been found anywhere i n p l a c e and must have been brought to the Vaughan M o u n t a i n by i c e . I t s h o u l d be n o t i c e d t h a t a change i n c o u n t r y from q u a r t z - d l o r l t e t o d i o r i t e /nay o r may ore d e p o s i t s .  n o t have an e f f e c t on  What i n f o r m a t i o n we have from the 411  seems t o p o i n t t h a t g a l e n a i s more m a s s i v e , and s p h a l e r i t e and a r s e n o p y r i t e . en d e f i n i t e l y y e t .  But  rock,  tunnel  there i s l e s s  t h i s p o i n t has not been p r o v -  So i n f o r m a t i o n i s a v a i l a b l e which way  the  contact d i p s * 2)  PYXES.  The  g r a n i t i c rock  ( q u a r t z - d i o r i t e and d i o r i t e ) i s  out by numerous p a r a l l e l b a s i c dykes s t r i k i n g n o r t h e a s t . dykes are h o r n b l e M e - l a m p r o p h y r e . few  inches  to a b o u t 40 f e e t .  The  They range i n w i d t h f r o m a  Come o f the dykes are  mineralised,  o t h e r s , e s p e c i a l l y the s m a l l e r ones a r e e n t i r e l y b a r r e n .  It  seems t h a t there i s no d i f f e r e n c e i n the dykes t h e m s e l v e s , and t h a t the m i n e r a l i z a t i o n o f the l a r g e r dykes i s due d i n a l f a u l t i n g and  to l o n g i t u -  f i s s u r e s , which d e v e l o p e d , because the  lar-  g e r d y k e s were l e s s competent than the s m a l l o n e s . I t has been siiown by the 4100 lamprophyre dyke may  l e v e l t h a t a t depth the  nhange i n t o a q u a r t z - p o r p h y r y .  change does not a f f e c t the e n t i r e d y k e . Dyke the q u a r t z - p o r p h y r y  This  I n case o f the  #2  i s on the hanging v a i l s i d e o f the  139.  dyke,  while the normal b a s i c m a t e r i e l i s on the f o o t - w a l l s i d e . T h i s change i n composition apparently represents f u r -  ther d i f f e r e n t i a t i o n of the dyke m a t e r i a l , and does not seem to a f f e c t the m i n e r a l i z a t i o n .  The s m a l l e r dykes at the same h o r i -  zon do not show t h i s f e a t u r e . More i n f o r m a t i o n about t h i s change i n dyke composition w i l l be gained, a f t e r r a i s i n g from 4100 to 4300 l e v e l .  The cor,tact o f quartz-porphyry dyke and  lamprophyre dyke should be watched f o r very c l o s e l y as i t i s l i k e l y that the change w i l l be g r a d u a l . The dykes have been f a u l t e d both l o n g i t u d i n a l l y and transversely.  I n a d d i t i o n s l i g h t movements have taken place  l o n g i t u d i n a l l y without causing displacement.  All these move-  ments have crushed and ground the dyke, and subsequent seepage of water has o x i d i z e d and decomposed the dyke to a great depth, r e s u l t i n g i n bands of gauge.  The l o n g i t u d i n a l movements appar-  e n t l y preceded the m i n e r a l i z a t i o n , while the transverse were post m i n e r a l i z a t i o n .  The l o n g i t u d i n a l f i s s u r e s provided the  path f o r m i n e r a l i z i n g s o l u t i o n s to come upward, and l a t e r provided channels f o r water to p e r c o l a t e down and cause secondary -  enrichment near the s u r f a c e . The dykes are not uniform i n w i d t h , but p i t c h and swell.  In some cases o f f - s h o o t s are g i v e n out a t low angles  to the main dyke.  Granite horses are f r e q u e n t l y i n c l o s e d w i t h -  i n the dykes. Besides the basic dykes, the country rock i s cut by a set  of A p l i t i c dykes.  These dykes are mostly narrow, n o t over  2 f e e t i n w i d t h , and i n no case heve been observed  t o be miner-  140. alized.  They a r e c u t t i n g the b a s i c dykes a t a f a i r l y h i g h a n g l e ,  and a r e l a t e r t h a n t h e lamprophyre d y k e s .  P r o b a b l y these dykes  r e p r e s e n t t h e a c i d end phase o f the q u a r t z - d i o r i t e . ORE DEPOSITS. The o r e , w i t h e x c e p t i o , o f t h e G r a n i t e Y e i n , o c c u r s i n v e i n s w i t h i n t h e dykes.  In g e n e r a l the v e i n s a r e w e l l d e f i n e d  though they are b o r d e r e d  by some r e p l a c e m e n t  and i n some p l a c e s , o f the g r a n i t e I t s e l f ,  p  o f t h e dyke rock I n w i d t h they v a r y  from a few i n c h e s up t o f i v e f e e t and i n a few cases a r e even wider, dykes,  A l t h o u g h sometimes o c c u r i n g i n t h e i n t e r i o r o f the they show a p r e f e r e n c e f o r t h e w a l l s and f o r t h e margins  o f s l a b - l i k e i n c l u s i o n s o r h o r s e s of g r a n i t e . The c h i e f s u l p h i d e s a r e a r s e n o p y r i t e , s p h a l e r i t e , g a l e n a , p y r i t e , c h a l e o p y r i t e and p y r r h o t i t e .  Tetrahedrite  o c c u r s s p a r i n g l y , w h i l e c o v e l l i t e , c h a l c o c i t e , p r o u s t l t e and p r o b a b l y some o t h e r s i l v e r s u l p h i d e s and a r s e n i d e s a r e p r o b a b l y secondary.  The predominant gangue m i n e r a l i s q u a r t z ,  glassy- i n appearance.  The v e i n s a r e u s u a l l y t i g h t , b u t  o c c a s i o n a l l y q u a r t z l i n e s vugs o r shows comb s t r u c t u r e .  The  mine a l i z e t i o n v a r i e s ' from f i l l i n g o f pure q u e r t z and coarse g r a i n e d s u l p h i d e s t o replace/?©nt of the dyke r o c k by q u a r t z c a r r y i n g f i n e g r a i n e d a r s e n o p y r i t e and p y r i t e w i t h g r a i n s o f other sulphides. C o n t r a r y t o the i m p l i c a t i o n o f the term ''mineralised dykes"  t h e o r e i s c o n f i n e d l a r g e l y t o t r u e v e i n s w i t h i n the  dykes and t h e a i l i c i f i e d dyke r o c k g r a d e s i n t o e n t i r e l y un-  141. m i n e r a l i z e d dyke m a t e r i a l . The s i l v e r appears to be e n t i r e l y with the galena, t h i s holds true of upper and lower l e v e l s es has been shown by numerous assays.  Gold i s e i t h e r f r e e i n the gangue, or assoc-  i a t e d w i t h a r s e n o p y r i t e . There i s no d e f i n i t e r a t i o of gold to s i l v e r .  The s i l v e r to l e a d r a t i o commonly i s 1 oz. per 15  Pb. Examination o f s e v e r a l p o l i s h e d s e c t i o n s under microscope , and core l a t i n g the sequences of m i n e r a l i z a t i o n i n d i c a t e s s e v e r a l periods of m i n e r a l ! '.:a t i o n i n the f o l l o w i n g manner; 1) C r y s t a l l i n e quartz 3) Galena 3) S p h a l e r i t e 4) P y r i t e , P y r r h o t l t e , Arsenopyrite 5) Chaleopyrite 6) Quartz 7) Galena 8} P y r i t e 9) M a r c a s i t e  10) P y r a r g y r i t e 11) Quartz {chaloedonic f i l l i n g f r a c t u r e s ) IE) C a l c i t e . This sequence i n d i c a t e s s e v e r a l generations of quartz and might mean that three m i n e r a l i z i n g periods were experienced. But t h i s should not be regarded as d e f i n i t e and f u r t h e r work w i l l have to be done.  142. The development work i n 4 3 0 0 l e v e l , has shown t h a t the h i g h grade ore body i n 4 5 0 0 l e v e l i s changed to a r s e n o p y r i t e and p y r r h o t i t e c a r r y i n g v e r y low v a l u e s . c o n d i t i o n e x i s t s i n 4 1 and 42 t u n n e l s .  P r a c t i c a l l y the same The h i g h g r a d e ore  shoot o f 4A changes to A r s e n o p y r i t e i n 4 E .  I t i s therefore  p o s s i b l e t h a t t h i s may be an i n d i c a t i o n o f a g e n e r a l c o n d i t i o n . That i s , t h a t h i g h grade o r e shoots a r e t e r m i n a t e d  by h e a v i l y  m i n e r a l i z e d shoots o f a r s e n o p y r i t e and p y r r h o t i t e .  I f this i s  c o r r e c t i t would be a d v i s a b l e , w h i l e c o n t i n u i n g t h e d r i f t s i n 4100 l e v e l t o r a i s e , or d r i l l , on w e l l m i n e r a l i z e d s h o o t s of i r o n s u l p h i d e s , i n the hope o f g e t t i n g i n t o h i g h grade g a l e n a s p h a l e r i t e l e n s e s above. The G r a n i t e V e i n .  The G r a n i t e V e i n p r e s e n t s an e n t i r e l y  differ-  ent type o f v e i n f r o m the v e i n s found i n d y k e s .  So f a r o n l y  one v e i n o f t h i s k i n d i s known on the p r o p e r t y .  The v e i n  f i l l s a s h e a r o r f i s s u r e i n the q u a r t z - d i o r i t e i t s e l f . gangue i s q u a r t z .  The  The s u l p h i d e s a r e v e i l c r y s t a l l i z e d , and a r e  low i n i r o n . I t s occurrence  c l o s e to the main |2 v e i n , d i p , and  s t r i k e and presence o f l a r g e w e l l formed c r y s t a l s o f p y r i t e and galena a t f i r s t  suggested secondary o r i g i n , by l e a chin'- of the  main -}2 V e i n , and r e d e p o s i t i o n i n a f i s s u r e ; but more c a r e f u l examination  o f t h e q u a r t z seems t o c o n t r a d i c t t h i s v i e w .  A more  d e f i n i t e answer c o u l d be o b t a i n e d by a m i c r o s c o p i c a l examination.  I t seems t h a t i t i s a t r u e q u a r t z v e i n , c a r r y i n g  g a l e n a , s p h a l e r i t e and p y r i t e .  The gold i s low.  D r i f t i n g on  t h i s v e i n should g i v e v a l u a b l e i n f o r m a t i o n a s r e g a r d s  to i t s  142A  c o n t i n u i t y and v a l u e s .  143. GEOLOGICAL H I S T O R Y .  E a r l y i n t h e MEsozoio E r a - I n Upper J u r a s s i c t i n e The  Coast Range B a t h o l i t h was i n t r u d e d I n t o e a r l i e r sediments  t h r o u g h o u t the whole d i s t a n c e from the Yukon southward i n t o United  States.  The g r a n i t e o f Yaughan M o u n t a i n was p r o b a b l y  p a r t o f t h i s g r e a t b a t h o l i t i c i n t r u s i o n and s o l i d i f i e d  under  c o v e r o f hundreds i f n o t thousands o f f e e t . A t l i n Ruffner  Mine.  I t was b e l i e v e d by s e v e r a l g e o l o g i s t s t h a t v i s i t e d the mine, t h a t c r u s t a l a d j u s t m e n t s i n v o l v e d i n the c o o l i n g and t r a n s f e r o f so l a r g e a mass o f m a t e r i a l caused f r a c t u r i n g i n the r e c e n t l y s o l i d i f i e d g r a n i t e and the f r a c t u r e s so formed were f i l l e d w i t h more b a s i c m a t e r i a l coming up from depth and f o r m i n g the l a n p r o p h y r e dykes.  T h i s i d e a i m p l i e s t h a t the  dykes were e s s e n t i a l l y contemporaneous w i t h the g r a n i t i c  intru-  s i o n and came from the same s o u r c e . However, more d e t a i l e d s t u d y o f t h e problem suggests a d i f f e r e n t course o f events. Deposits"  ... L l n d g r e e n i n n i s " M i n e r a l  on Page 166 s t a t e s :  " I n t h e l i t e r a t u r e many a u t h o r s a t t r i b u t e f i s s u r e v e i n s i n e f f u s i v e rocks reason.  to c o n t r a c t i o n , but u s u a l l y w i t h o u t  sufficient  The t e n s i l e s t r e s s e s cannot produce l o n g f i s s u r e s w i t h  r e g u l a r s t r i k e and d i p " and f u r t h e r on page 170. " . . . t h e r o c k s w h i c h have f o r m e r l y  been f a r below t h e  s u r f a c e o f t h e e a r t h , but w h i c h have been exposed by e r o s i o n are u s u a l l y t r a v e r s e d by more o r l e s s r e g u l a r j o i n t systems, p e r s i s t e n t over l a r g e areas."  These j o i n t systems L l n d g r e e n ,  L e i t h and o t h e r prominent g e o l o g i s t s a t t r i b u t e t o r e g i o n a l  144. coinpressional It  stresses.  i s t h e r e f o r e c l e a r t h a t the f i s s u r e s which were  l a t e r f i l l e d with  dyke m a t e r i a l o r i g i n a t e d l o n g a f t e r the con-  s o l i d a t i o n o f g r a n i t e , probably daring building period,  t h e n e x t mountain  i . e . Laramide r e v o l u t i o n o r l a t e r .  A f t e r t h e dykes s o l i d i f i e d t h e y themselves underwent fracturing. due in  L o c a l l i z i n g o f t h e f r a c t u r e s and t h e dykes was  i n p a r t t o the c o n t r a c t i o n o f t h e dyke r o c k on c o o l i n g and p a r t t o t h e c o n t i n u e d a p p l i c a t i o n o f t h e same f o r c e s w h i c h  o r i g i n a l l y opened t h e f i a s u r e a .  I n o t h e r words, t h e dyke  f i s s u r e c o n t i n u e d t o be a l i n e o f weakness and was reopened a f t e r c o o l i n g o f the dykes. Into  the f i s s u r e s i n the dykes so opened t h e o r e  d e p o s i t i n g s o l u t i o n s ascended.  I t f o l l o w s from the above t h a t  m i n e r a l i z a t i o n was post J u r a s s i c , p r o b a b l y p o s t L a r a m i d e , and o c c u r r e d sometimes d u r i n g  T e r t i a r y , v e r y l i k e l y d u r i n g the  O l i g o c e n e , which i s c o n s i d e r e d by J c h o f i e l d  t o be the next  mineralizing period a f t e r J u r a s s i c . T h e i r o r i g i n was p r o b a b l y t h e same magma which  furnished  the,, dyke r o c k b u t t h e d i f f e r e n t i a t i o n which produced t h e o r e bearing  s o l u t i o n s o c c u r r e d i n d e p t h and n o t w i t h i n the dykes  themselves. and  These s o l u t i o n s c a r r i e d s i l i c a , s u l p h u r ,  the metal3  i r o n , z i n c , l e a d , c o p p e r , s i l v e r and g o l d ,  b e s i d e s c e r t a i n l y some f l u o r i n e and p r o b a b l y o t h e r  mineralizers  w h i c h have escaped from the s o l u t i o n i n gaseous form.  #  arsenic  This  r  3. J . S e h o f i e l d , Ore D e p o s i t s o f B. c.  Mem. 132, p.63  145.  s o l u t i o n not only deposited s i l i c a and m e t a l l i c minerals i n the f i s s u r e s themselves but i n the dyke rock and to some extent the g r a n i t e , r e p l a c i n g the w a i l rock by quartz and other ore minerals.  Apparently the m i n e r a l i z i n g s o l u t i o n s came up not  once but about three times d e p o s i t i n g new minerals and r e p l a c i n g the o l d e r ones.  There was  some d i f f e r e n t i a t i o n i n the  v e i n , so Galena and s p h a l e r i t e came higher than the i r o n sulphides.  There was a deep cover of rock o v e r l y i n g even the  highest part o f the present surface at the time the veins were formed, and t h i s has been removed by e r o s i o n which followed the e l e v a t i o n o f the Coast Range In e a r l y Mesozoic and the subsequent r e - e l e v a t i o n o f e a r l y T e r t i a r y time when the Rockies were formed. The veins have a l l the c h a r a c t e r i s t i c s o f ore deposits formed at intermediate temperature and pressure (rae so thermal deposits) whose depths o f formation Lindgren describes as from 8000 to 12,000 f e e t .  The heat and pressure accompanying  b a t h o l l t i c i n t r u s i o n may have made i t p o s s i b l e f o r deposits of t h i s s o r t to form somewhat nearer the surface i n some p l a c e s . I t i s p o s s i b l e to place the temperature range even more d e f i n i t e l y and to say that i t approached the h o t t e r end o f intermediate temperature.  The r e g u l a r i t y o f the v e i n s , absence  o f b r e o c i a t i o n and c r u s t i f i o a t i o n and presence of p y r r h o t i t e exclude the p o s s i b i l i t y t h a t the veins are o f low temperature origin.  On the other hand, the absence of such minerals as  garnet, araphibole, pyroxene, e t c . , coupled w i t h the presence o f te.inantite and the appearance of the quartz exclude a high temperature (hypothermal) o r i g i n .  The coarse t e x t u r e o f the  146. s u l p h i d e s , general absence o f vugs ana r a r i t y of comb s t r u c t u r e and occurrence o f p y r r h o t i t e p o i n t toward the warmer end o f intermediate temperature. Further i t i s p o s s i b l e to say that the high temperature end was towards west, which e x p l a i n s g r e a t e r amounts o f p y r r h o t i t e and a r s e n o p y r i t e , and l e s s massive galena c a r r y i n g lower values i n s i l v e r .  I t i s therefore reasonable to expect b e t t e r  grade s i l v e r - l e a d ore f a r t h e r e a s t , which w i l l also extend to a g r e a t e r depth.  This has been w e l l demonstrated both by the  4100 t u n n e l and the surface workings higher up on the mountain. The s i g n i f i c a n c e o f the f a c t t h a t tne deposit i s of an intermediate temperature type, I s , that me3othermal deposits are  In g e n e r a l more p e r s i s t e n t than those o f low temperature. M i n e r a l i z a t i o n o f the same g e n e r a l type i n veins o f  t h i s nature l a *:nown i n many parts o f the world to p e r s i s t throughout a v e r t i c a l range o f 1000 feet and i n some eases even 2000 f e e t or more and h o r i z o n t a l l y f o r d i s t a n c e s o f many thousands o f f e e t , though any s i n g l e vein does not n e c e s s a r i l y pers i s t throughout the e n t i r e range.  Experience has shown that i n  such ore copper values o f t e n increase i n depth, which has been demonstrated by our 4100 l e v e l , though the d i f f e r e n c e i n elevat i o n necessary to produce any n o t i c e a b l e change i s r e l a t i v e l y l a r g e — o n the order o f 1000 f e e t or more. On the other hand, primary d e p o s i t s o f bonanza s i l v e r Ore are formed at lower temperature, and i f found I n a deposit of t h i s type would occur nearer the o r i g i n a l surface or f a r t h e r out from the center o f m i n e r a l i z a t i o n ,  any extremely r i c h ores  found here w i l l probably be o f secondary o r i g i n .  147. Secondary Barlohment. f h e h i g h s i l v e r v a l u e s so f a r found are i n ore t h a t l i e s near the dation*  s u r f a c e and  l a a l l cases shows more o r l e s s  fhe specimens from 4500 l e v e l open c u t s and a d i t wnieh  gave assays o f 500 o z . and  over c o n s i s t e i t h e r o f e a r t h y b l a c k  oxidized m a t e r i a l or of galena c a r r y i n g v i s i b l e fhe  oxi-  ruby s i l v e r ,  l a t t e r m i n e r a l i s a s t r a n g e r t o primary ore o f the  temperature mesothermal type and may richment.  b e s t be explained by  The earthy ore carrying l i t t l e l e a d may  v a l u e s In f i n e l y  disseminated  higher en-  have I t s  native s i l v e r , c h l o r i d e s o r  s i l v e r sulphides. The o c c u r r e n c e  o f the b e s t secondary ore i n the  exposures so f a r opened up may  lowest  a t f i r s t seem anomalous but  be understood when the topography i s c o n s i d e r e d .  I n the  may  first  p l a c e , deep f r a c t u r i n g w h i c h g r e a t l y f a c i l i t a t e s enrichment  may  have a l s o been a v i t a l f a c t o r i n i n f l u e n c i n g e r o s i o n to form a v a l l e y i n this p l a c e . early period may  the g l a c i a l p l a n i n g o f tne  have removed secondary ores from the  parts of the h i l l . h i l l may  Secondly,  higher  T h i r d l y , erosion on the higher part of  the  have been so f a s t as to have overtaken enrichment. I f enrichment under modern climatic  conditions may  c o n s i d e r e d i t must a l s o be remembered that h i g h on the h i l l  be the  ground i s perpetually frozen. Sven i n l a t e summer and  at d i s t a n c e s of 100  feet or  more below the s u r f a c e the open fractures a r e a l l f i l l e d with *  i c e , and tals.  abandoned tunnels soon become l i n e d up w i t h ice crys-  Thus f r o s t i s retarding i f not altogether p r e v e n t i n g  ground-water c i r c u l a t i o n  i n the upper p a r t s of the h i l l while  L  148. at  l o w e r e l e v a t i o n vadose c i r c u l a t i o n c o n t i n u e a .  tic  changes  from c e n t u r y t o c e n t u r y would s h i r t  f r o z e n ground w a t e r up o r down.  Slight clima-  the l i n e o f  S t i l l another c o n s i d e r a t i o n  t h a t must n o t be o v e r l o o k e d i s t h a t a l l  the open c u t s and  underground w o r k i n g s so f a r d r i v e n on t h e upper s l o p e s o f t h e h i l l have been where s u r f a c e showings were b e s t , hence where the  e r o s i o n has been l e a s t deep, and c o n s e q u e n t l y the a r e a s o f  deepest f r a c t u r i n g have been a u t o m a t i c a l l y a v o i d e d . S e c o n d a r i l y e n r i c h e d o r e s have so f a r shown such h i g h v a l u e s t h a t they r i c h l y r e p a y a c t i v e s e a r c h , p a r t i c u l a r l y as the to  depth t o w h i c h they e x t e n d i s not known and may o f f e r very considerable  be such as  tonnages.  The d e t e r m i n i n g f a c t o r s f o r secondary o r e s seem to be: 1} P r e s e n c e o f g a l e n a f u r n i s h i n g s i l v e r v a l u e s i n the p r i m a r y ore. 2)  F r a c t u r e zones a l o n g which e n r i c h i n g s o l u t i o n s may  pass  downward. 3) P r e s e n c e o f G a l e n a , s p h a l e r i t e or c h a l e o p y r i t e as a precipitant. 4} P r o t e c t i o n from g l a c i a l o r r a p i d s u r f a c e e r o s i o n w h i c h has removed e n r i c h e d o r e . In  p r o s p e c t i n g f o r e n r i c h e d ore I t would be w e l l t o r a i s e on any  g a l e n a - r i c h s h o o t s e n c o u n t e r e d i n deeper workings i n the hope o f f i n d i n g e n r i c h m e n t s n e a r the s u r f a c e . ter  U n t i l c o n d i t i o n s are b e t -  u n d e r s t o o d , i t would a l s o be a w i s e experiment t o r a i s e sph-  a l e r i t e s h o o t s , even though they may  not show good s i l v e r v a l -  ues i n the p r i m a r y o r e , s i n c e s p h a l e r i t e i a an a c t i v e p r e c i p i t and o f secondary m i n e r a l s and may  be e n r i c h e d near the s u r f a c e .  149 • POSSIBILITIES.  Humber 2 dyke has been t r a c e d f o r more than 6000 f t . h o r i z o n t a l l y , and 2000 f e e t v e r t i c a l l y . definitely  #4 dyke has not been  t r a c e d f o r the same l e n g t h , but i t s s i z e where ex-  posed, makes i t h i g h l y p r o b a b l e t h a t i t c o n t i n u e s  as f a r as #2.  T a k i n g #2 dyke from e l e v a t i o n 4100 t o the s u r f a c e and comparing i t s t o t a l a r e a , w i t h t h a t p a r t o f i t w h i c h has been opened up, i t i s a p p a r e n t , t h a t o n l y a very s m a l l p o r t i o n o f the dyke has been e x p l o r e d .  I t comes t o a p p r o x i m a t e l y  6$.  I n t h i s 6;i o f t h e a r e a o f t h e dyke s e v e r a l ore bodies have been d i s c o v e r e d , and a t l e a s t one d e f i n i t e l y b l o c k e d  out. I t i s  t h e r e f o r e p r o b a b l e t h a t o t h e r o r e oodles e x i s t i n the u n e x p l o r e d p o r t i o n o f the dyke.  I n a d d i t i o n t o t h e p o r t i o n o f the dyke  above 4100 l e v e l , t h e type o f d e p o s i t makes i t p o s s i b l e f o r ore t o e x t e n d f a r t h e r down f o r a c o n s i d e r a b l e  distance.  I n s e v e r a l p l a c e s a l o n g the s u r f a c e , namely 2A, 2B, & 20 shoots o f h i g h grade o r e have been found,  -..one o f t h e s e o r e  s h o o t s has been t e s t e d f o r I t s e x t e n t downward; but the 4100 l e v e l g i v e s us e v i d e n c e t h a t g a l e n a and s p h a l e r i t e a r e extendi n g f o r a t l e a s t 1000 f e e t below t h e s u r f a c e . Ho. 4 v e i n has the same p o t e n t i a l p o s s i b i l i t i e s as #2 vein.  And t h e r e a r e i n d i c a t i o n s t h a t g a l e n a i s more m a s s i v e  in this vein. Between #2 and #4 v e i n s l i e s a l a r g e a r e a , whose topography seems t o i n d i c a t e c e r t a i n p o s s i b i l i t i e s . l i k e depression  The low s a u c e r  I n t h e c e n t r e , and a' t r o u g h c o n n e c t i n g  i t with  the #2 v e i n system might I n d i c a t e an a r e a where e r o s i o n has been  150. more r a p i d because o f p o s s i b l e s e r i e s o f f a u l t s or f i s s u r e s . As shown elsewhere on the property such depressions u s u a l l y i n d i c a t e presence o f dykes.  I t i s therefore p o s s i b l e , that one  or s e v e r a l dykes o f the basic type, or maybe "Granite" type may occur i n t h i s r e g i o n . I t mast be remembered that t h i s i s only a conjecture, and that there are no p o s i t i v e i n d i c a t i o n s o f dykes on the surface.  But as i t i s planned to d r i v e a cross-cut from a2. to #4  veins t h i s i s an i n t e r e s t i n g p o s s i b i l i t y .  I f i t turned out as  hoped, i t would add g r e a t l y to the value o f the mine. The ore shoots are i n general s h o r t , and the high grade lenses narrow.  There are i n d i c a t i o n s that they might follow i n  eschelon, but so f a r no i n f o r m a t i o n i n regard to c o n t r o l l i n g f a c t o r s o f ore body l o c a t i o n s i s a v a i l a b l e . The distance between ore bodies, as shown on the surface i s about 2000 f e e t .  SUMJAHY.  1) Veins are u s u a l l y a s s o c i a t e d w i t h basic dykes, but may a l s o be i n q u a r t z - d i o r i te. 2} Chief gangue minerals are quartz and c a l e i t e , i n some eases sulphides are disseminated i n dyke i t s e l f . 3} Veins p r e f e r margins o f the s t r u c t u r e s , and u s u a l l y are on the f o o t w a l l s i d e o f the dyke.  I n case o f 4100, the best  m i n e r a l i z e d part o f the v e i n i s on the contact o f quartzporphyry and lamprophyre. 4J Ore bodies are terminated by arsenopyrite and p y r r h o t i t e .  151* 5) H i g h v a l u e s may  he found near the s u r f a c e o v e r l y i n g s t r o n g  l e a s e s o f g a l e n a and s p h a l e r i t e ,  a d v i s a b l e to r a i s e  on  such l e n s e s . 6} S i l v e r accompanies g a l e n a . Vfo j?b.  Common r a t i o i s 1 0 2 . ag p e r  Gold i s e i t h e r f r e e i n the gangue o r accompanies  arsenopyrite. 7) Galena and S p h a l e r i t e a r e p r i m a r y and may  be expected  through a v e r t i c a l and h o r i z o n t a l range o f s e v e r a l  thousand  feet. 8) The o r e was  formed under c o n d i t i o n s o f i n t e r m e d i a t e tempera-  t u r e and p r e s s u r e . 9} B e t t e r grade ore i s more l i k e l y t o o c c u r f a r t h e r e a s t , and go deeper t h e r e t h a n a t 4300 l e v e l , because the h i g h e r temperature seems t o have been west o f p r e s e n t w o r k i n g s . 10) Ore s h o o t s a r e c o m p a r a t i v e l y s h o r t .  B o r d e r s o f commercial  o r e can be b e s t determined by a s s a y i n g . 11) Ore s h o o t s are. spaced about 2000 f e e t , h o r i z o n t a l l y  from  each o t h e r , as a t p r e s e n t i n d i c a t e d by s u r f a c e -workings.  152. Atlin  District. Copper  Veins.  "Copper v e i n s o c c u r on the s o u t h w e s t e r n eox*ner o f Copper I s l a n d i n a t l i n Lake.  The r o c k  formation c o n s i s t s of reddish  and g r e e n i s h , p r e v a i l i n g l y c o a r s e l y t e x t u r e d , o l i v i n e b a s a l t s and  t u f f s ; the t u f f s , however, predominate and  i n places consist  almost e n t i r e l y o f b a s a l t i c f r a g m e n t s , but grade i n t o r o c k s c o n t a i n i n g a predominance o f s e d i m e n t a r y m a t e r i a l s . The  r e d d i s h b a s a l t s range i n c o l o u r from b r o w n i s h r e d  to g r e e n i s h r e d , and  are d i s t i n c t l y b a s a l t i c i n h a b i t .  groundaass i s always c r y p t o o r y s t a l l i n e and c o n t a i n s o f o l i v i n e and  The  phenocrysts  a u g i t e as w e l l as p a r t i c l e s o f i r o n and  oecas-  s i o n a l l y n a t i v e c o p p e r , a l l o f w h i c h are r e a d i l y v i s i b l e to unaided eye.  I n p l a c e s the groundmass becomes r e l a t i v e l y  i n amount, c a u s i n g the r o c k s t o have a d e c i d e d l y  the  small  granular  appearance. Th©  g r e e n i s h b a s a l t s are c h a r a c t e r i s t i c a l l y dark o l i v e -  g r e e n I n c o l o u r , and d i f f e r from the r e d d i s h v a r i e t i e s , i n c o n t a i n i n g much l e s s I r o n , to w h i c h l a due  the red  chiefly  colour-  ation. The  Veins.  A number o f v e i n s from a f r a c t i o n o f an i n c h to  6 Inches i n t h i c k n e s s o c c u r i n f i s s u r e s i n these b a s a l t i c r o c k s , and  c o n s i s t mainly  o f c a l c i t e , but a l s o , i n p l a c e s  con-  t a i n p a r t i c l e s and masses o f n a t i v e c o p p e r , tne l a r g e s t o f w h i c h known to have been f o u n d , i s r e p o r t e d about 40 pounds. {D. D. C a l r n e s .  to have weighed  A c e r t a i n amount o f m a l a c n i t e 0. 3. C.  Mem.  37.  p. 114  -  as w e l l as r a r e 116).  153. p a r t i c l e s o f c u p r i t e and t e n o r i t e o c c u r as o x i d a t i o n p r o d u c t s o f the n a t i v e  copper."  D. D . C a i r n e s c o n c l u d e s  from h i s e x a m i n a t i o n o f t h e  d e p o s i t s t h a t t h e c o p p e r was d e p o s i t e d I n a n a t i v e s t a t e . I n r e g a r d t o the o r i g i n o f copper he s a y s :  "As t h i s  m i n e r a l i n t i m a t e l y a s s o c i a t e d w i t h the i r o n which i s d e c i d e d l y p r i m a r y t o the b a s a l t s , i t might be supposed t h a t t h e copper had t h e same o r i g i n .  However, t h e copper both i n th© v e i n s and  w a l l s i s q u i t e t h e same, and t h a t I n the v e i n s i n a c a l c i t e gangue I s u n q u e s t i o n a b l y secondary  to the b a s a l t s .  Some have  supposed t h a t t h e v e i n copper has been l e a c h e d f r o m t h e a d j o i n i n g w a l l s where t h i s m i n e r a l I s thought tuent.  t o be a p r i m a r y  consti-  I f t h i s were so t h e r e w o u l d be a d e c r e a s i n g amount o f  copper i n the w a l l s as t h e v e i n s a r e approached.  Instead, quite  the o p p o s i t e appears t o be t h e c a s e , and t h e copper i s much more p l e n t i f u l I n t h e b a s a l t s a d j o i n i n g v e i n s and o t h e r  fissures.  I t , t h e r e f o r e , seems e v i d e n t t h a t a l l the copper both i n the w a l l s and v e i n s was d e p o s i t e d a t the same p e r i o d and was i n t r o duced by u p r i s i n g s o l u t i o n s , p r o b a b l y d e r i v i n g t h e i r m i n e r a l c o n t e n t from t h e s t i l l h e a t e d l o w e r p o r t i o n s o f the b a s a l t i c magma, and t h a t t h e g r e a t amount o f i r o n o r e i n t h e upper c o o l e r p o r t i o n s o f the b a s a l t s caused t h e copper t o d e p o s i t i n t h e native  form." The l a s t s t a t e m e n t ,  i n r e g a r d t o c o p p e r coming from  the same b a s a l t i c magma does n o t seem very c o n v i n c i n g . I t seems much e a s i e r t o a t t r i b u t e the f o r m a t i o n o f t h i s d e p o s i t t o t h e Coast Range . B a t h o l i t h , w h i c h i s j u s t a few m i l e s west o f the occurrence.  154. The b a s a l t s themselves a r e o l d e r than the g r a n i t i c intrusion,  and I b e l i e v e t h a t there a r e  no known m i n e r a l  d e p o s i t s a s s o c i a t e d w i t h r o c k s o f t h i s age i n the d i s t r i c t .  Antimony V e i n s . A d e p o s i t o f t h i s t y p e I s known t o e x i s t about 10 m i l e s n o r t h o f Golden Gate.  The ore o c c u r s  i n form o f bedded v e i n s ,  i n the d a r k , f i n e l y t e x t u r e d s h a l e s o f Laberge s e r i e s . main v e i n I s made o f q u a r t z and a t i b d i t e w i t h some  The  galena.  Very l i t t l e development has been done, so that p r a c t i c a l l y n o t h i n g e l s e i s known about the d e p o s i t .  155. Atlin District.  Econ. G e o l .  C o n t a c t Metamorphic Contact-inetamorphic  Qeposita.  d e p o s i t s o f economic i n t e r e s t have  been found i n A t l i n d i s t r i c t o n l y i n one  l o c a l i t y which i s s i t -  uated on Haboe Greek n e a r the upper end o f T o r r e s C h a n n e l , an arm o f A t l i n L a k e . The  7 a l l e y o f the c r e e k I s u n d e r l a i n p a r t l y by  schists,  q u a r t z i t e s , l i m e s t o n e s , e t c . , o f the l o w e r l i t . S t e v e n s g r o u p , the ag©  o f w h i c h , C o c k f i e i d p l a c e s t e n t a t i v e l y to  "Pre-Carabrian."  A d j o i n i n g t h e s e r o c k s on the "west a r e the Coast Range g r a n i t i c I n t r u s i v e s . The c o n t a c t metamorphic ore d e p o s i t s are I n c l u d e d i n the Mt. granitic  intrusives.  Ore d e p o s i t . 150  Stevens r o c k s near t h e i r c o n t a c t w i t h the  The  ore d e p o s i t i s a t one p o i n t  approximately  f e e t i n t h i c k n e s s , and wherever a s e c t i o n o f the  rocks  below the g r a n i t i c i n t r u s i v e s has been seen, a t l e a s t 30 to 40 f e e t o f o r e - m a t e r i a l has been found; t h i s c o n s i s t s m a i n l y magnetite,  of  hematite, c h a l c o p y r l t e , t e t r a h e d r i t e , malachite,  c o b a l t bloom, and v a r i o u s s i l i c a t e s  including considerable  y e l l o w g a r n e t , a p p a r e n t l y g r o s s a l a r i t e , and  some b i o t i t e .  The r o c k t h a t has been a l t e r e d and r e p l a c e d i n the f o r m a t i o n o f the o r e - m a t e r i a l s appears t o have been m a i n l y , i f not e n t i r e l y , the M i l e s t o n e which o c c u r s i n bands o f v a r i o u s t u i c k -  (Robertson,  >/. F.  R e p o r t on the M i n i s t e r o f M i n e s ,  (D. D. C a i r n e s , C. S. C.  Mem.  37.  p.  117.)  1904)  156. . noaa i n the l i t . Stevens s e r i e s , b a t I n p l a c e s the l i m e s t o n e has s u f f e r e d m e r e l y r e e r y s t a l l i z a t i o n and m a r b l e i n a t i o n . The  b e s t showing i s on the F r e n c h c l a i m , on which a  c r o s s - c u t t u n n e l 188 f e e t l o n g has been d r i v e n , o:' whieh more t h a n 130 f e e t i s i n t h e ore-body; t h i s a s s a y s from 1.65;* t o 6;£ c o p p e r , and i t l a thought t h a t a c o n s i d e r a b l e p o r t i o n o f i t w i l l average between 2$ and 4$.  The d e p o s i t e x t e n d s up t o  w i t h i n a few f e e t o f the g r a n o d i o r i t e c o n t a c t which l a about 50 i n e l e v a t i o n above t h e v a l l e y . Other showings do n o t show t h e same h i g h grade o r e , but  t h i s i s not c o n c l u s i v e s i n c e o n l y a few s h o r t  are known.  The r e s t o f t h e c o n t a c t i s covered  outcrops  with d r i f t .  G e n e s i s and Age o f D e p o s i t s . " I n s t u d y i n g the g e n e s i s o f t h e s e d e p o s i t s a number o f s t r i k i n g and d e f i n i t e p o i n t s have been n o t e d .  In the f i r s t  p l a c e , the m i n e r a l s c o n s t i t u t i n g the o r e body o r o r e b o d i e s are c h i e f l y m a g n e t i t e ,  s p e c u l a r ! t e , hematite, c h a l e o p y r i t e ,  t e t r a h e d r l t e , p y r i t e , y e l l o w g a r n e t , and o t h e r complex cates. phides and  This combination  o f Hematite and m a g n e t i t e w i t h  silisul-  i s v e r y c h a r a c t e r i s t i c o f c o n t a c t metamorphic d e p o s i t s  I s p r a c t i c a l l y unknown i n f i s s u r e v e i n s .  F u r t h e r , A hen  these m i n e r a l s o c c u r w i t h y e l l o w g a r n e t and r e l a t e d s i l i c a t e s an a s s o c i a t i o n i s produced w h i c h i s d i a g n o s t i c o f c o n t a c t metumorphisra.  157. F a r t h e r , these ore-minerals  o c c u r o n l y near the  intrus-  i v e g r a n o - d i o r i t e c o n t a c t , and have d i s t i n c t l y been produced by r e p l a c i n g the l i m e s t o n e s  intercalated  i n the Mt.  Stevens  series. f h e r e t h u s a p p e a r s t o be l i t t l e o r no t h e s e o r e s owe and  t h e i r o r i g i n t o the n e i g h b o u r i n g  doubt, but what granodiorites  t h a t the m a t e r i a l s composing them s e r e d e r i v e d f r o m t h e  g r a n o d i o r i t e magma, as the l i m e s t o n e and r o o k s do not c o n t a i n the n e c e s s a r y for their  adjoining schistose  i r o n , copper, and  sulphur  production.  The c o n t a c t o r e - m a t e r i a l s on these p r o p e r t i e s a r e , t h e r e f o r e , In a l l p r o b a b i l i t y  due  to magmatic v a p o u r s , r i c h i n  I r o n , copper and s u l p h u r , which were d e r i v e d f r o m t h e g r a n i t i c intrusive  body.  I f t h i s i s t r u e t h e d e p o s i t s were formed  d u r i n g the c o o l i n g p e r i o d o f the g r a n i t i c b a t h o l i t h , w h i c h as e x p l a i n e d under " g e n e r a l  geology," i s thought to have o c c u r r e d  i n J u r a s s i c and  l a t e J u r a s s i c time.  probably  158.  PART  IV.  Bibliography  159. PART I V . Bibliography. B a n c r o f t , J . A.  G e o l o g i c a l Survey o f Canada.  Memoir 2 3 , 1913.  Bateraan, A. M.  G e o l o g i c a l Survey o f Canada.  Summ.  R e p t . 1912.  B u d d i n g t o n , A. F. 1) "Coast Range I n t r u s i v e s o f S o u t h e a s t e r n A l a s k a . " Jour. Geol. 2) U. S. G. S.  B o s t o c k , H» S.  G. S. C.  Y o l . 35.  So. 3, 1927.  B u l l e t i n 800.  Summ. R e p t . 1929.  "Geology and Ore D e p o s i t s o f K i c k e l P l a t e M o u n t a i n , H e d l e y , B. C."  B r o c k , R.  G. 3* C.  Summ. Rept. 1920.  "Eutsuk Lake D i s t r i c t , 3 . C." "Reoonaissance o f Ootaa,  B r o o k s , A. H.  1} U. 3. G. S.  tfhitesail  and Eutsuk L a k e s .  P r o f , paper Ho. 45  "Geography and Geology o f A l a s k a . " 2) U. 3. G. S.  Annual r e p o r t .  P a r t 2. 1900.  "A R e o o n a i s s a n c e from Pyramid Harbour t o E a g l e City,  Alaska."  160. 0. 5. G a i r n e a . 1) G. 3 . 0.  Suaa. R e p t . 1920.  " C o q u i h a l l u A r e a , B. 0." 2) G. 3. 0.  Soma. R e p t . 1922.  " G e o l o g i c a l E x p l o r a t i o n s i n Y a l e and Similkameen Mining 3} G. 3. G.  Divisions."  Memoir 139.  " C o q u i h a l l u A r e a , B. C " 4}  G. S. C.  Soma. K e p t . 1929.  "The S e r p e n t i n e  B e l t o f Coqaihalla Region,  Y a l e D i s t r i c t , 3.  C"  C a i r n e s , D. D. 1) G. S. C.  Memoir 5, 1910.  " P r e l i m i n a r y Memoir on t n e Lewes and Ifordens k i o l d R i v e r a C o a l D i s t r . , Yukon  territory."  2) G. 3. 0.  Memoir 3 1 .  "rfheaton  District."  3} G. 3. 0.  Memoir 3 7 .  "Portions of Atlin  D i s t r i c t , B. C." 4)  G. S. C  Memoir 67.  "The Y u k o n - A l a s k a  I n t e r n a t i o n a l Boundary between P o r o u p i n e and Yukon R i v e r s . " 5} G. S. C.  Suora. R e p t . 1910. "Portions of A t l i n  District."  1914.  161. C a i r n e s , D. D. 6}  (contd.)  0.  S.  C.  3arma. R e p t .  1916.  " P o r t i o n s o f Conrad and ./hitehorae M i n i n g Districts. 7} G. S. C.  n  Summ. R e p t .  1915.  "Mayo A r e a ; and C o r o g g i e , B a r k e r , T h i s t l e , and Kirkman C r e e k s , ; and Wheaton D i s t r i c t Yukon 8) G. S. C.  Territory." Memoir 50  "Upper ./kite R i v e r D i s t r i c t . " 9) "Canadian T e l l u r i u m — c o n t a i n i n g o r e s . " J o u r . Canadian M i n i n g I n s t i t u t e , " 1911, p.192-4. 10) "Economic P o s s i b i l i t i e s o f Yukon" Canadian I n s t i t u t e o f Met.  T r a n s . V o l . X V I I I (1915)  Camsell, Charles. 1) G. 3. C.  Mem.  26.  "Geology and M i n e r a l D e p o s i t s  o f Tulameen D i s t . B. 2) G. 3. C  Mem.  Hedley M i n i n g 3) "The  2.  C."  "Geology and Ore D e p o s i t s o f  Division."  o r i g i n and H i s t o r y o f the Great Canyon o f  the F r a a e r R i v e r . " T r a n s . R o y a l Soc. Canada.  V o l . 14, see. 4,  1920.  C o c k f i e i d , . >/. 3* 1) G« 3. C»  Summ* R e p t . 1920. • " S i l v e r Lead D e p o s i t s  o f t h e Keno H i l l A r e a , Mayo, Yukon." Z) G. S» C Southern 3) 0. 3. G.  Surara. Rept. 1922.  "Explorations i n  Yukon." Summ. R e p t . 1923.  " S i l v e r Lead D e p o s i t s  o f Beaver R i v e r A r e a , Yukon."  "Geology and Ore  D e p o s i t s o f Keno H i l l , Mayo D i s t r i c t . 4) G . S. C.  Summ. R e p t . 1925.  "Explorations  A t l i n and T e l e g r a p h C r e e k , B. C." Deposits o f A t l i n D i s t r i c t , 5) G. S. C.  between  " S i l v e r Lead  3. C."  Summ. R e p t . 1926.  " A i s k l h i k Lake 6} G. 3 . C.  ? 1  District."  Summ. R e p t . 1927.  "Dezadeash Lake -\rea, Yukon." 7) G. 3 . C.  Summ. R e p t . 1929.  "The M i n i n g I n d u s t r y o f Yukon."  E. and. B e l l , A . H.  Cockfieid,  G. 3. C.  Memoir 150, 1926.  "i/hitehorse D i s t r i c t ,  Yukon."  D a l y , R. A. " T h e n o m e n c l a t u r e o f'A., i . C o r d i l l e r a between the 4 7 t h and 53rd p a r a l l e l s o f l a t i t u d e . Geog.  Journal.  J u n e , 1906, p. 588.  163. loImage, f . 1} G.3.C 2}  3oram. R e p t . 1924, "Chiko Lake & V i c i n i t y . " • "  "  1925, " T a t l a - 3 e l l a Goola  3}  "  "  "  1928, "Gun  4}  "  "  "  1922.  Dawson, 0.  .reu."  Creek Map .frea,  B.C."  M.  1) G.S.C.  Rept. o f P r o g r e s s .  1875-76.  "Report on e x p l o r a t i o n s I n B r i t i s h 2) G. S. C.  1887.  "Report on e x p l o r a t i o n o f Yukon 3) G. S. C.  Columbia."  Annual R e p o r t .  District."  V o l * 7,  1894.  "Suram. Report o f i n v e s t i g a t i o n s i n s o u t h e r n 3. 4) G. 3. C.  V o l . X I I p. B.  "Report on A t l i n f i n i n g 5) G. 3. C .  C."  1899. District."  Sumra. Rept., 1896.  Vol. VII.  6) " G e o l o g i c a l Record o f Rocky Lmt. B u l l . G e o l . l i o c . o f America.  region."  V o l . 12, p.. 60.  7) "On the l a t e r physiographical geology o f the Rocky f o u n t a i n R e g i o n i n Canada." T r a n s . R o y a l S o c i e t y , fanuda. 8) G. S. Q,  Annual R e p o r t .  1894.  V o l . 8, Sec. 4, Vol.. V I I .  P.  1690. 10B.  Garwood, J5. J . " F e a t u r e s o f a l p i n e Scenery due t o G l a c i a l Geog. J o u r n a l .  S e p t . 1910.  p. 317.  protection."  164. Gwillim, J * C . 1} R e p t . t o t h e M i n i s t e r o f F i n e s , B. G, 1889,p.652-4. 2)  G.S.C.  inn. Rept.  V o l . H I 1899. p. on., - 7 5 1 .  "Report o n A t l i n M i n i n g D i s t r i c t . " 3) G.S.C. 4}  Annual Rept. V o l . A l l I 1900 p.52A - 62A.  "Notes on A t l i n G o l d F i e l d s . " J o u r . Can. K i n . I n s t . 1900, p. 97 - 102.  5) " C h a r a c t e r i s t i c s o f A t l i n Gold F i e l d s " J o u r . Can. M l n . I n s t . 1902. p. 21 - 3 3 .  Hanson, G. 1) G.S.C.  Suram. R e p t . 1922. P.A.  " R e c o n n a i s s a n c e between K i t s a u l t R i v . and Skeena R i v e r , B. C." 2) G.S.C.  Summ. Rept. 1923.  "Reconaissance between Skeena R i v e r and S t e w a r t , 3. C . " 3) G.S.C.  Summ. Rept. 1924.  " P r i n c e R u p e r t t o Burns L a k e . " 4)  G.S.C.  Summ. Rept. 1925.  "Recouaissanoe i n Zyraoetz R i v e r .jrea." 5} G.S.C.  Suram. Rept. 1928.  " M i n e r a l D e p o s i t s o f A l i a e Arm D i s t r i c t . "  Hanson, G. and P h e m i s t e r , T. C . G.S.C.  Summ. R e p t . 1928. "Topley Map A r e a , B* C .  165.  H u r s t , M. S. C. S. G.  Summ. Rept. 1924.  "Tungsten D e p o s i t s near H a z e l t o n , B. C."  J o n e s , R. H. B. G. S. C.  Summ. Rept. 1 9 2 5 .  "Geology and Ore D e p o s i t s o f Hudson Bay M o u n t a i n , Coast D i s t r i c t , B. C."  K e r r , ?. A. 1} G.S.C.  Summ. Rept. 1925.  "Dease Lake a r e a , C a r r i a r D i s t r . , B. C." 2) G.S.C.  Summ. Rept. 1926.  " P r e l i m i n a r y Rept. on S t i k i n e R i v . A r e a , 8. G." 3) G.S.C.  Suram. Rept. 1928.  "Second P r e l i m i n a r y Rept. on S t i k i n e R i v . a r e a . " 4} G.S.C.  Sums. Rept. 1929.  "Taku R i v e r D i s t r i c t , B. C " "Pre 11.-iinary Report o n I s k u t R i v e r A r e a . "  Lang, A . H. G. S. C.  Sum. R e p t . 1929.  "Owen Lake M i n i n g Camp."  L e a c h , W. 1) G.S.C. Summ. Rept. 1909. "Skeena R i v . D i s t r . " 2)  "  "  "  1910.  11  "  "  166 • L i n d g r e n , W»  "Mineral  Deposits."  M a c k e n z i e , J . D» 1) G. 3. C  Surara. R e p t . 1920.  "The l i m o n l t e d e p o s i t s o f Taseko V a l l e y " "A R e o o n a i s s a n c e between Taseko Lake and Fraser River." " C h i l c o Lake."  Mandy, J . D. 1) M i n i s t e r o f Mines R e p o r t s 1929, 1930. " A t l i n Section." . 2) M i n . o f Mines Rept. 1929.  p. 133 C.  "Taku R i v e r A r e a . " 3) K i n . o f l i i n e s Rept. "Taku R i v e r  B u l l . 1, 1930.  District."  M a r s h a l l , . J . R. 1) G. S. 0.  Summ. Rept. 1924.  " V / h i t e s a i l - T a h t s a Lakes A r e a , B . G." 2) G. 3. C.  Summ. R e p t . 1925.  "Eutsuk Lake a r e a , 3. C." 3) G. S. C.  Summ. R e p t .  1926.  " L a k e l s e Lake Map A r e a , Coast D l s t r . 8. C.  167. M c C o n n e l l , R. G. 1) G.S.C.  arm. R e p t .  V o l . XI7  p a r t B.  "Report on K l o n d i k e G o l d F i e l d s . " 2) G.S.C.  nan. R e p t . V o l . I V , 1888 - 1889.  3)  "  Summary R e p o r t 1904.  4}  "  "V/hitehorse Copper B e l t . "  5)  "  Summary R e p o r t 1912.  1909.  " G e o l o g i c a l s e c t i o n a l o n g t h e Grand Trunk P a c i f i c R. R. from P r i n c e R u p e r t to Alderraere." 6} G. S. C  Memoir 3 2 , 1913.  " P o r t i o n s o f P o r t l a n d C a n a l and Skeena M i n i n g D i v i s i o n s , B. C."  McCann, W. S. G. S. C.  Memoir 130, 1922.  "Geology and M i n e r a l D e p o s i t s o f t h e B r i d g e R i v e r Map A r e a , 3. C."  0*Heill, J . J. G. S. C.  Liemoir 110, 1917.  " P r e l i m i n a r y R e p t . on t h e Economic Geology o f the H a z e l t o n D i s t r i c t .  V. J . O k u l i t c h . "Geology o f t h e A t l i n R u f f n e r Mine" r e p o r t t o t h e manager o f the f l i u e , 1931.  168. Reineeke L e o p o l d . G. S. C.  Memoir 118.  " M i n e r a l D e p o s i t s between L i l l o o e t  and P r i n c e  George, B. 0." R o b e r t s o n , R. P. Annual R e p o r t .  M i n i s t e r o f M i n e s 1898. "  1900.  "  ^  1904.  "  1910.  S o h o f i e l d , 3. J . 1) G. 3. 0.  Memoir 117.  "Geology and Ore d e p o s i t s o f ..insworth M i n i n g Camp, 3. 0." 2) "The G e o l o g i c a l Record o f C o r d i l l e r a i n Canada T r a n s , o f t h e R o y a l S o c . Canada V o l . X V I I , lii  s e r . 1 9 2 3 , p. 79.  3} " F i s s u r e systems o f B r i t i s h Canad. I n s t .  M i n . & Met.  Columbia" J u l y , 1925. •  4) "The B r i t a n n i a M i n e s , B. C." Economic Geology,  V o l . 2 1 , ho. 3, 1926.  5) "Ore D e p o s i t s o f B r i t i s h Chap. I V . Memoir 132.  Columbia" G. 0. C.  S c h o f i e l d , S. J . and Hanson, G. G.S.C. Memoir 132.  "Geology and Ore Deposits o f Salmon R i v e r A r e a . "  169 S t o c k w e l l , C. H. G. S. G.  Summ. Hept. 1925.  "Galena H i l l , Mayo D i s t r i c t , Yukon."  S p e n c e r , A . G. " P a c i f i c M o u n t a i n System I n B r i t i s h Ooiumb and  alaska."  B u l l . G e o l . S o c . o f ..aaerica, Y o l . 14.  V e s t g a t e L e w i s , G. i j . a. (>. S.  d u l l . 722 C. P. 117.  "Ore d e p o s i t s o f trie Salmon Iii v e r  Young, R o s a l i n d , ./. " M i n i n g i n A t l i n , B. G." .Tourn. Can. l i i n . I n s t . 1909.  District  140°  139  C  138  c  136  137  135°  c  c  133'  134'  132'  131°  130  c  129'  128  126°  127  c  c  125°  124°  123  122 [7  e  120'  121'  c  119'  116'  r  \  \  114°  115'  TH EC UNI VER 5 / T Y  or  112  111*  c  US'  BlR/T/SEf  COLL/MB/A  \ G£O  THE  LOG/C/)  CO/4ST  M/* P  Z  59  R//NGE  BATHOL/TH.  JS/elsoi \Gate  i FORTI PNELSO  58°  58  E  T  Beatt,.  \  . anov y  57  N  56 iFt.Grahaine  56  /93JI E  Cttnim  4 f tfobcrlv  N  T  \  \aoiial  K  M*  V  -I  55  .  sT^^T 0 0  QtrtnanB  'Takla Landing  {Grande •"Prairie,  V  54 Salmon  *Dcwey Foreman"  4? *  *  B  Ii  iA  53  un  tctMa't  53  A  -^f  5?  Quetmet  Tete Jaune  11':,;, W  Clem'ma;  * \T\  d V l  11I0B0  52  0  jUexand  52 SoJa Orcwi  Harpers! knye".  Alexin Crook/  Wil^J  Alto"  C j  I11500  Exeter  v p o « OJ-eek  e L  Deer  _ I  R.,  51  feiacfcPool  Lake mOti* ADAMS)  green ljafie Taseho\  x  T .  LPavirfS-li aylm'Vo \ L ^r? P»po Soot  50  MMWb^XMKm& HONOURABLE  V  INVRT  Srt^" "  'rBonouu DIP  ttita tgeni*  JLAB3TO  T. D, P A T T U L L O ,  Campl-Spll Rival ylJQ  1,1  T K| A  v  Alia Lake \A»P0U  Powel Rivert  A  RVDOUA  Y.  e  VE  0^  M i n i n g R e c o r d e r O f f i c e s O ATLIN  Railways  Sub-Recorder Offices  133  c  49  ^ O I ^ Q OlWer <^T&mVWoa ^ " f l b ™  SlaJne Lth^  ,0  1M  •>i Mt.Baker «fW / ,ellM|ha4 10,827 A . / 6  t  T  Land Districts _ .  132  e  r  s  J  W  K  J A !Tld  WoreiUe  •48  R1A  © Moyio  131°  f r ^ i k o  X  L E G E N D  134°  f  h  ObUlilw'H<J  135°  ARtty  \ T\ jSope••50i'.(\pper lMt.  160  4 ^/^  (LAKE  ^» * N cou ^^^^L^* S^  H0  7.IKI  1  1  B  T M I  SguamiBliji/  Scale, 50 miles to 1 inch 100  0r07e  Buttle; LcfKe  j»*  49  136°  50  XA  MINISTER ,v , Jervi8\  48°  Lai  130°  129° Longitude 128°  127°  West  126°  125°  from 124°  121°  119'  118'  117*  116  c  115° MAP  N ° |CX  

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