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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 V l a d i m i r J . O k u l i t c h B. A. Sc. Thesis submitted f o r the degree of s/aster of Applied Science. Department of Geology Faculty of Atsoliea Science. The U n i v e r s i t y of B r i t i s h Columbia. A p r i l , 1932. 2. Table o f Contents* Page. Foreword. 4 P a r t 1. Introau.eti.on and Summary. & (a) Topography and physiography. 7 (b) General geology. 8 (c) Economic geology. il P a r t 2 . 1. Topography and Physiography. 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 ) T r a n s i t i o n a l Zone. 24 £. B r i e f G e o l o g i c a l H i s t o r y 2? 3. General Geology. (a) The Coast Range B a t h o l i t h . 30 (b) Table of Formations. 39 (c) D e s c r i p t i o n o f Formations. 39 4. Economic Geology. 54 (a) D e s c r i p t i o n of Ore Deposits. Part 3. ( A t l i n D i s t r i c t ) 95 1. Topography and Physiography. o£ 2. General Geology. 101 (a) Table of formations - 102 (b) D e s c r i p t i o n o f formations. 1Q4 3. Economic Geology. (a) Gerieral. H j Page. (b) D e s c r i p t i o n of Ore Deposits. 117 P a r t 4. B i b l i o g r a p h y . 158 Appendix. Foreword. This 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 f i r s t deals w i t h the e n t i r e area under c o n s i d e r a t i o n , while the second describes the A t l i n d i s t r i c t . This d i v i s i o n was deemed necessary because of the g r e a t e r f a m i l i a r i t y o f the author w i t h the A t l i n d i s t r i c t , where he spent two summers doing g e o l o g i c a l work, f o r a mining company. Thus the , - i.tlin d i s t r i c t i s d e s cribed 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 the only sources of i n f o r  mation were repo r t s and the memoirs of the G e o l o g i c a l Survey of Canada, and the M i n i s t e r of Mines r e p o r t s . The t h e s i s , except the Dart d e a l i n g w i t h the ^ t l i n R uffnor mine, does not represent o r i g i n a l work, but i s a corn- D i l a t i o n of g e o l o g i c a l data assembled duri n g the l a s t 20 or 30 y e a r s . The l i t e r a t u r e on the subject i s so e x t e n s i v e , that a great d e a l o f time and a t t e n t i o n was required to separate the 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 unoroven. The conclusions are summarised and b r i e f l y state.* i n the P a r t I of the t h e s i s . They represent thoughts which were r a i s e d i n the author's mind w h i l e reading and comparing f a c t s observed i n d i f f e r e n t narts o f the area. These conclusions are by no means of equal v a l u e . Some are obviously t r u e , some are j u s t s p e c u l a t i o n s . They were nut down not so much f o r t h e i r own v a l u e , but r a t h e r as notes f o r f u r t h e r reference and study. Not enough i s yet known of the composite nature and h i s t o r y o f the great Coast Range B a t h o l i t h , very l i t t l e i s 5. known of the country to the east of 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 are aangerous, but 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 progress i s to be made i n the f u t u r e , gen e r a l i z a t i o n s are necessary." I wish to thank a l l those who helpeu me w i t h the work of 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 Dr. 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 of the s u b j e c t made h i s ad 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 wish to thank L!r. C. L. Hershiaan, manager of the Engineer and At 11 n Ruffner Mines, whose i n t e r e s t and knowleage of geology made I t po s s i b l e f o r me to study the geology i n the v i c i n i t y of the mines i n f a r gr e a t e r d e t a i l than 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 g e o l o g i s t . The general g e o l o g i c a l man, included w i t h the t h e s i s , was coonile-«. on the b a s i s o f reports of the G e o l o g i c a l Survey of Canada, issued d u r i n g the l a s t 10 ye a r s , and BO represents the l a t e s t and most accurate knowledge of the area. I b e l i e v e t h i s i s the f i r s t map, on which the eastern contact of the E a t h o l i t h , was p l o t tea. along i t s e n t i r e l e n g t h , from f i e l d o b s e r v a t i o n s . PART I . I n t r o d u c t i o n and Summary. 6 Along the e n t i r e western coast of the American c o n t i  nent extends a long and rugged system of mountain chains and r a n g e s — t h e C o r d i l l e r a of Worth ana South America. The westernmost ranges i n B r i t i s h Columbia, belonging to the C o r d i l l e r a , are the Coast Range and the I s l a n d Ranges. fhe Coast Range i s taade of g r a n i t i c i n t r u s i v e rocks and i s f l a n k e d by o l d e r sedimentary 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 heat of i n t r u s i o n . Along the margins o f t h i s g r a n i t i c body, c a l l e d the Coast Range B a t h o l i t h , are found numerous o r e - d e p o s i t s . I t i s b e l i e v e d t h a t these o r e - d e p o s i t s were formed by emanations a r i s i n g from 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 geology of the ore d e p o s i t s along the e a s t e r n contact o f the B a t h o l i t h , not so much In the d e s i r e to b r i n g out o r i g i n a l hypothesis on t h e i r o r i g i n , but r a t h e r to b r i n g together 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 copious l i t e r a t u r e on the s u b j e c t . In order to do t h i s i n t e l l i g e n t l y i t i s necessary to get acquainted not only w i t h the geology of the separate ore- de-DOsits, but a l s o w i t h the general geology and physiography of the d i s t r i c t , and the v a r i o u s hypothesis brought forward to e x p l a i n the observed f a c t s . 7 Physiography and Topography. {Summary) The Coast Range extends along the western coast of B r i t i s h Columbia; i n the south i t i s separatea from the Cas cade Range by the v a l l e y o f Pra s e r R i v e r , and i n the nor t h connects w i t h the mountain systems of A l a s k a . To the east of the Coast Rang© l i e s the I n t e r i o r P l a t  eau, made mostly o f sedimentary and v o l c a n i c r o c k s . The Coast Range i t s e l f i s made almost e n t i r e l y of g r a n o - a i o r i t e of 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 are the two main physiographic provinces of the area under c o n s i d e r a t i o n . The Coast Range i s rugged, w i t h bold o u t l i n e s and i r r e g u l a r e r o s i o n f e a t u r e s . I t i s a l s o of a g r e a t e r average height than the P l a t e a u to the 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 cut i n i t , w i t h s o f t rounded o u t l i n e s , and i s considerably lower i n e l e v a t i o n that the Coast Range, There i s no sudden break between the Pl a t e a u ana the 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 to the average l e v e l of the Range. The general u n i f o r m i t y of e l e v a t i o n , and the f a c t t h a t streams cut through the Coast Range suggest the idea that the Coast Range and the P l a t e a u behind were pene- planated and then 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 played an important r o l e i n the s c u l p  t u r i n g of the present topography, and even now g l a c i e r s are s t i l l found i n the Coast Range. 8. General Geology. The rocks of the Ea s t e r n s i d e of the Coast Range may be subdivided i n t o three 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 great bulk of f o r  mations to the east of the great Coast Range B a t h o l i t h . They are both sedimentary and v o l c a n i c r o c k s , and range In age from "Pre-Cambrian to'Lower Cretaceous. As the B a t h o l i t h was not intru d e d i n the same time throughout i t s l e n g t h i t l a Impos s i b l e to say d e f i n i t e l y where the border 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 rocks should be drawn. In some areas the Lower Cretaceous i s d e f i n i t e l y p o s t - b a t h o l i t h i c , w h i l e i n o t h e r s , the i n t r u s I v e s cut the lower members o f the Lower Cretaceous, 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 rocks, the Pre-Cambrian and the Palaeozoics are found i n the n o r t h ; the Pre-Cambrian 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 south as S t i k i n e and l a k u t R i v e r s . They appear again i n the south as the Cache Creek and Bridge R i v e r s e r i e s . From Stewart to Bridge R i v e r Area i n the south ern B r i t i s h Columbia the rocks are p r e v a i l i n g l y Mesozolc. The T r l a s s i o i s represented i n the S t i k i n e and l a k u t R i v e r s areas i n the n o r t h , and i n the Bridge R i v e r and Gun Creek areas i n the south. The J u r a s s i c i s w e l l represented throughout, and there f o r e represents an imnortant p e r i o d of sedimentation. The main geological feature of the d i s t r i c t under con sid e r a t i o n i s the Coast Range B a t h o l i t h . The Batholith repre sents 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 into Yukon t e r r i t o r y , a distance of about 1000 miles. I t i s anywhere from 60 to 100 miles wide. Apparently i t does not represent a single period of i n t r u s i o n , but was intruded during several periods; i t also varies l i t h o l o g i c a l l y from point to point, 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 Jurassic time and t h i s period therefore i s considered to be the period of i n t r u s i o n . The e a r l i e s t i n t r u s i o n , however, probably occurred i n Lower Jurassic or even T r i a s s i c age, and the separate intrusions of parts of the main B a t h o l i t h , and smaller s a t e l l i t i c Batholiths continued Into Cretaceous and possibly l a t e r . The Batholith l a made c h i e f l y of l i g h t gray, grano- d i o r i t e ; but a l l gradations from galbro to true granite e x i s t . I t i s possible that, as the changes from one rock to the other are abrupt, the d i f f e r e n t material 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 materially from each other, the main difference being the degree of rueta- morDhism, and width of metamorphic zone; that on the eastern contact being quit© narrow and less affected than the one on the western side. This difference had very pronounced effect on ore deposition, and i s treated i n considerable d e t a i l 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 rooks have no importance from the view p o i n t of economic geology s i n c e the great majority of ore depo s i t s are connected w i t h the i n t r u s i o n o f the B a t h o l i t h . But to make the d e s c r i p t i o n complete i t may be s a i d that the Upper Cretaceous i e represented at s e v e r a l p o i n t s , and that the T e r t i a r y i s represented mainly by v o l c a n i c f l o w s , s c a t  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 . The quaternary d e p o s i t s c o n s i s t mostly 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 rocks and l a v a s . 11. Economic Geology. Summary. fhe ore d e p o s i t s along the eastern 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 smaller b a t h o l i t h s i n the i n t e r  i o r p l a t e a u . I t i s quite p o s s i b l e t h a t these s m a l l e r batho l i t h s are d i r e c t l y connected w i t h the main b a t h o l i t h , but there i s no evidence f o r . t h i s except the l i t h o l o g i c a l s i m i l a r i t y , i s i s s t a t e d , i n the chapter on the Coast 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 placed i n the tipper J u r a s s i c Time, although 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  truded i n Lower Cretaceous and T e r t i a r y t i m e . The s a t e l l i t i c b a t h o l i t h s i n the i n t e r i o r are considered by some to be contem poraneous w i t h the Coast Range B a t h o l i t h , w h i l e others place them as l a t e as the Laramide r e v o l u t i o n . Probably there Is q u i t e a v a r i a t i o n i n age among them, and the B a t h o l i t h s were intruded a t v a r i o u s times from J u r a s s i c to the Laramide and maybe l a t e r . I t i s t h e r e f o r e reasonable to consider that 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 . I t may be w e l l at t h i s p o i n t to consider the i n t e r e s t i n g p o s s i b i l  i t y that the type of ore d e p o s i t , i . e . i t s mineral content, may be i n f l u e n c e d by i t s age, or r a t h e r by the age of the parent i n  t r u s i v e mass. There are i n d i c a t i o n s that t h i s /nay be the case. P r . S. J . S c h o f i e l d has a p p l i e d the zonal theory of formation of ore d e p o s i t s , and has shown that the p r e v a i l i n g m i nerals on the eastern f l a n k of the Coast Range B a t h o l i t h are 1 2 . g o l d , s i l v e r , l e a d and z i n c ; and on the western f l a n k — c o p p e r . This g e n e r a l i z a t i o n i s very v a l u a b l e 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 ore d e p o s i t i o n . But a t any p a r t i c u l a r place the ge n e r a l law may be o f f s e t by l o c a l c o n d i  t i o n s . These l o c a l c o n d i t i o n s a r e ; (a) The composition o f g r a n i t i c magma i n t h i s l o c a l i t y . (b) The c h a r a c t e r of country rock. (c) Distance of the d e p o s i t from the contact. I t i s a w e l l e s t a b l i s h e d f a c t , that the composition of 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 from place to place i n the Coast Range B a t h o l i t h . I t i s a l s o w e l l e s t a b l i s h e d t h a t the B a t h o l i t h i s composite, and t h a t d i f f e r e n t p o r t i o n s of i t may be of d i f f e r e n t age. Dr. S c h o f i e l d has d i s t i n g u i s h e d three phases, the B r i t a n n i a , the Columbia, and the Caledonia phase, and there may be more. I t l a q u i t e p o s s i b l e that 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 . In the Whitehorse d i s t r i c t , D. D. Cairnes s a i d that the Contact Metamorphic Copper d e p o s i t s are d e f i n i t e l y o l d e r than the s i l v e r — l e a d — g o l d d e p o s i t s . I t i s not p o s s i b l e t h a t ,-; copper was brought by the e a r l i e r phases of the i n t r u s i o n , which d i d not reach the present s u r f a c e , thus producing only mesothermal and eplthermal v e i n d e p o s i t s ? In some cases i t i s d e f i n i t e l y shown, t h a t the o l d e r g r a n i t e had to be f r a c t u r e d before t h i s second stage 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 than the f i r s t , copper phase, the s i l v e r — g o l d — l e a d min e r a l s would predominate. 13. The second, p o i n t , the c h a r a c t e r of the country r o c k , does not seen to i n f l u e n c e the d e p o s i t s very 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 formations* The 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, but 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 p a r t — t h e age of i n t r u s i v e ; however, besides t h a t , i t s e f f e c t i s very s i m p l e , and r e s u l t s only i n a l o c a l d i s t o r t i o n of the main zo n a l arrangement. Thus copper d e p o s i t s extend i n a narrow b e l t almost a l l way a l o n g the e a s t e r n contact of the B a t h o l i t h , although a c c o r d i n g to the general z o n a l arrangement t h i s should have been a g o l d — s i l v e r — l e a d s i d e . 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 only l o c a l  l y , while the zonal 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 seen that the mines on the western f l a n k are copper producers, while the ones i n the east are producers of g o l d , s i l v e r , lead and z i n c . 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 are 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 type, w h i l e to the south the g o l d quartz v e i n s predominate i n importance. To sum up the p e c u l i a r i t i e s of the economic geology of the eastern s i d e o f the B a t h o l i t h i t i s best to t a b u l a t e the d i f f e r e n t f a c t s . 14. Conclusions. By studying the ore deposits on the eastern side of the Coast Range Bath o l i t h th© f o l l o w i n g points were noted. (!) The ore deposits are g e n e t i c a l l y connected with the Coast Range Intrusives which apparently range from Upper Jurassic to Tertiary i n age. Ho ore deposits a r e found i n the i n t e r i o r region, 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 deposits. I t i s necessary i n conjunction with 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 available minerals at a point. In connection w i t h t h i s shear zones and f i s s u r e s appear to be e s p e c i a l l y important. (3) Ro commercial deposits have been found close to the contact with 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 holiths are important, several deposits are found r i g h t i n the b a t h o l i t h s , and other deposits often d i f f e r  ing from the conventional 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 certai n gradation of rtfavourabllityn may be observed. Schofield grades the rocks as follows; 1. limestones, 2. g r a n i t i c rocks, 3. diorite-gabbro family, 4. volcanic t u f f , 5. quartzites, 6. s l a t e s . The age of the formation, provided i t i s pre-batholi-15. t h i c , does not seem to play any part. (6) The ore deposits of the Eastern contact may he divided into two main groups, (1) High temperature deposits, mostly contact metamorphic copper deposits, (2) Intermediate and Low temperature deposits, forming veins, with galena, lead, z i n c , gold, 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 indications that these two groups belong to two per iods of min e r a l i z a t i o n , one immediately following the i n t r u s  ion,—producing the copper deposits; and the other some tima l a t e r , may be connected with the next movement of the magma, which did not reach the present surface, and so produced only- deposits of intermediate or 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 fractured by l a t t e r movements. P. D. Cairnes says: "From the evidence so f a r accumulated the age of the vein deposits 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 to be in l i t t l e doubt. They are l a t e r than the period of consolidation of at least 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 miner a l i z a t i o n are indicated. I t i s also i n d i r e c t l y supported by the following words of Dr. Schofield; "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 deposits of the eastern contact are confined to a narrow b e l t near the contact, mostly i n limestones and i n 16. the granite 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 River Areas to Coguihalla Area, mostly as contact metamorphic, but some times as vein deposits. Hone of them have been worked with any success. (8) I t seems that gold i s more important mineral i n the south ern part of the area under consideration, and that s i l v e r - l e a d is 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 of various age are li k e l y to bring different 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 deposits. (10) From the commercial standpoint the Eastern side of the Batholith i s essentially a belt of gold, s i l v e r , lead and zinc minerals. The occurrence of copper is interesting only geolo g i c a l l y . (11) A l l important ore deposits of the eastern flanks are true vein type occurring either in fissures or shear zones. (IS) In several cases the mineralized fissures have a very constant strike and'dip, which in connection with their great length, indicates that these f i s s u r e s were formed by compree- sional stresses. The 1.1. or N.W. strike suggest that the pressure was coming from the west. 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 north westerly are generally characterized by the presence of copper minerals, while those s t r i k i n g north-easterly are known for t h e i r gold, 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.n B u l l . Can I n s t . Mining & Met. J u l y , 1925. 18. PART I I . Or© Deposits of the 'Eastern sm® of the Coast Hange B a t h o l i t h . 19 General Topography aM 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 belt of Korth America. The Canadian C o r d i l l e r a are part of a great mountain system which extends along the P a c i f i c Coast and i s continuous from the northern part of Rorth 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 follows; Homenolatxire of Mountains In Western Canada, 1918. (a} P a c i f i c System (b) Insular Systes Western B e l t . (Cascade Range [Coast Range. (Vancouver Island Range (Queen Charlotte Island Range 1st. S l i a s Range. (a) Columbia System (Gold Ranges) (b) I n t e r i o r System (c) Caasiar System (d) Yukon System Central Belt. ] Sel k i r k Range [Cariboo Range (Monashee Range (Fraser Plateau ( (Nechako Plateau Babine Range Istickeen Range. (Yukon Plateau. 30. Eastern B e l t . (a) Rockies System (b) A r c t i c System 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, since only the Eastern side of the Coast Range i s considered. !re may therefore make a general subdivision as follows: (a) The Coast Range. lb) The I n t e r i o r Plateau. The I n t e r i o r Plateau w i l l include a l l the region immediately east of the Coast Range proper, and such plateau regions as the Yukon, fleehako and Fraser Plateaus. 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 further discussion. (Rocky I t . Range (llacKenzie Range (Franklin Range ( F o o t h i l l s Range. (Richardson Range. 21. The Coast Range. The Coast Range i s mad® of several p a r a l l e l .ranges, trending northwest and southeast. In general th© Coaet Range i s very rugged, presenting a complex of needle l i k e peaks, saw-toothed ridges, and deep oanyon l i k e gorges. I n places the outli 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 of i t s forms. This can 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 of th© g r a n i t i c 'rocks of the Coast Range- B a t h o l i t h , and as no bedding planes are present the weathering and erosion produces ©oat fantastic forma. The elevation of the Coast Range varie s from South to North* In the .south the Range i s higher, and separate peaks reach the ele v a t i o n of IE,000 f e e t , while i n the north the elevations are around 8,000 feet. Shis change i n a l t i t u d e , though great, i s so gradual that i t does not break the apparent uniformity of summit l e v e l , whieh, however bears no r e l a t i o n to s t r u c t u r a l features* This terrane has thus been considered by a number of geologists who have studied i t topographically, to represent a peneplanated, or at least a mature to old surface of erosion, subsequently elevated. 22. I n t e r i o r Plateau-System. To the east o f the Coast Rang© l i e s a wide upland r e g i o n , which i n v a r i o u s p a r t s of the province i s g i v e n d i f  f e r e n t names such as 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 , but i s e s s e n t i a l l y the same physiographic province throughout, and ©an be best naaed as the I n t e r i o r P l a t e a u . I t i s an und u l a t i n g and i n places 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 defined ranges l i e w i t h i n t h i s "region and many, s i n g l e peaks and minor ranges r i s e above the p l a t e a u l e v e l . I n t o t h i s upland surface the main drainage courses have i n c i s e d channels v a r y i n g from. 3,000 to #,000 f e e t i n depth, thus producing a very i r r e g u l a r ' topography. The sum mits of unreduced h i l l s and r.i%@s, l y i n g between the water ways, mark a g e n t l y r o l l i n g pl&itt whi-eh slopes toward the no r t h and northwest. When viewed from one of the adjacent peaks of the Coast Range the steep, narrow v a l l e y s a r e e n t i r e l y l o s t to view and the i n t e r v e n i n g areas appear as a comparatively l e v e l p l a i n broken only 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 volcanic cone of recent o r i g i n . In some areas the I n t e r i o r plateau i s more than ordin- ary./level owing to the widespread 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 of g l a c i a l t i l l of s u r p r i s i n g l y uniform t h i c k n e s s . Cookfield, describing the plateau between A t l i n and 23. Telegraph. Creek says: w 1 ! e l l rounded or flat-topped h i l l s , and 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 to the northwest where I t i s known as the Yukon plateau, but the southern part of the area i s a vast lava plateau dissected to some extent, age of which r e l a t i v e to that of the plateau to the north i s unknown; i t may be con siderably younger." Along the northern portion of the Coast Range, the general suiamit l e v e l merges into that of the Yukon plateau, i n a maimer suggesting the' synchronous planation of these two provinces, a view that i s held by Brooks, Spencer, Cairnes and others; but during the various v e r t i c a l movements that have affected these terranes, the u p l i f t has been greatest • along the axis of the Coast Range and leas t along that of the Yukon plateau province, which terrace i s thus given the con tour 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 of the Yukon River from near i t s headwaters i n northern B r i t i s h Columbia to Bering 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. Marshall, to which they give the name "Tr a n s i t i o n s ! Zone." Quoting Marshall, "Between the Coast Range and the I n t e r i o r Plateau there l a a transition zone characterised by rounded, flat-topped mountains whose elevations gradually change from 3,000 feet in the east to 6,000 and even 7,000 feet in the west. The axes of the ridges in t h i s t r a n s i t i o n a l zone a l l trend at right angles to the. axes of the Coast Range, i . e . , northeast and southwest, and the ridges appear to pro ject fro© the Coast Range as a series of spurs. The width of t h i s zone l a approximately 15 miles. Each ridge i s a separate massif separated from i t s neighbours by broad, steep sided *W-* shaped v a l l e y s , also running northeast and southwest. The smooth, rounded o u t l i n e s and gentle east slopes of these several 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 features of the d i s t r i c t . The ridges forming t h i s t r a n s i t i o n a l zone undoubtedly once formed part of the Coast Range and possessed features similar' to i t . Following the p a r t i a l retreat of the continen t a l ice-sheet,' which covered even the highest peaks i n the J . R. Marshall. Sum. Rept. 1925. p. 144 ¥, Bolmage. Sum. Rept. 1924. p. 61. 25. area and l e f t i n i t s wake more or less smoothly rounded sum mits, huge tongues of ice remained on the higher summits, and i n the pre-existing v a l l e y s . These coalesced to form an Ice-sheet of lesser extent than that of the continental ice-sheet at th© time of i t s maximum development. Well-defined g l a c i a l terraces and smo othly truncated slopes on almost a l l of these ridges at appro ximately 2,800 feet above the valley bottoms are evidences of the e f f e c t i v e action of these ice 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 feature of t h i s zone i s , that numerous streams s t a r t i n the Coast Range proper, flow east ward through the "Transition Z o n e a n d then turn abruptly and flow west c u t t i n g the Coast Range, to the P a c i f i c Ocean. The fact 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 flowing eastward are probably more recent, and flow east becauae the Coast Range has higher ele vation that the Plateau region; 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 further supported by the fact that numerous of these east flowing secondary streams are captured by the main streams and thus made to flow westward. The higher elevation of the Transition Zone, can 2 6 . 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 roc its have been hardened by the heat during the i n t r u s i o n of the B a t h o l i t h , and so withstood the e r o s i o n b e t t e r , (2) She intrusion of the B a t h o l i t h u p l i f t e d the sedimentary 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 p l a c e s along the ea s t e r n 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 of these formations w i l l be found. 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 geo l 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 not the o b j e c t of 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 the 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 b r i e f d e s c r i  p t i o n of the main p o i n t s I s necessary. I t was e a r l y recognized by G. 1'. Dawson, that one of the main, problems to be s o l v e d i n B r i t i s h Columbia, i s to e s t a b l i s h the source from which the sediments eame. G.Ll. Daw son then brought forward h i s hypothesis that the Shuswap t e r  ra ne represented the o r i g i n a l source of sediments. S i m i l a r views, i n a general way, were l a t e r held by Daly. However, the explanation was not q u i t e s a t i s f a c t o r y , because of the e v i  dence that the sediments came from the west. Then S. J . S c h o f i e l d presented h i s hypothesis of the Casoadia Land i n the P a c i f i c , which agrees very w e l l w i t h the f i e l d evidence. The G e o l o g i c a l Record of the 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 . Transactions of the Royal Soc. of Canada, v o l . XVII. ser. i i i , 1923. P. 79. 28. "'This hypothesis supports the occurrence of a land mass, Cascadia, since 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 basin of sedimenta t i o n stretched 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 Palaeozoic and early Hesozoio basin of sedimen t 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 periods, stretched i n a northwesterly d i r  ection just west of the present ooast l i n e of ITorth America. The northern border of Cascadia extended i n a westerly d i r e c  t i o n j u s t south of the peninsula of Alaska. (3) During the Jurasaide r e v o l u t i o n , four great moun t a i n chains appeared i n t h i s basin. (a) The Vancouver Island—Queen Charlotte Island Range. The Coast Range of B r i t i s h Columbia, (a) The Sierra Nevada Range. (c) The S e l k i r k s and their extension northwards and south- warda—into the B i t t e r r o o t and Clearwater Ranges. (d) The Alaskldes on the northern border of Cascadia. (4) The granito Batholi ths which accompanied the Juraaside revolution were invaded during Upper Jurassic times. rl" (5) Basins o f Cretaceous sedimentation oocucced on both flanks of these Jurassic mountains. (6) These baalas i n Canada at l e a s t , were affected by the Laramide r e v o l u t i o n , which was accompanied also by igneous i n t r u s i o n s . (?) Small Tertiary basins of sedimentation with l o c a l outpourings of volcanic material marked the Lower Tertiary which was brought to a close by l o c a l mountain building and igneous i n t r u s i o n at the end of Oligocene. (8) Down f a u l t i n g and down f o l d i n g probably at the close of the Miocene, have buried the ancient land mass of Cascadia beneath the waters of the P a c i f i c Ocean. Yaat floods of lava were outpoured l a B r i t i s h .Columbia and Oregon. (9) The vulcaniaa of l a t e T e r t i a r y , Pleistocene, and the present p e r i o d s i s associated with the sinking of Cascadia, which has caused and is causing a period of tension along the P a c i f i c Coast.* This covers a l l the important phases of the geological history of B r i t i s h Columbia, and no more need be said 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 rea 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 deposits, since the great majority of ore deposits along i t s western and eastern contacts are i n d i r e c t connection with the i n t r u s i o n of t h i s enormous g r a n i t i c 1 mass. I t ranges from the International 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 miles wide i n the south and gradually tapers northward. The average width may "be taken as approximately 60 miles. In composition the B a t h o l i t h varies considerably,. The variation i s more pronounced transversely than longitudinaly. The core is usually grano-diorite, but nearer the eon- tact true d i o r i tes, quartz-dlori tes, and quartz-monzonltes occur. In places true granites have been reported; but in general i t may be sa i d , that vui sufficient data i s s t i l l avail able in regard to the petrology of the B a t h o l i t h . It i s now considered by most geologists that the Bttholith i s composite, and was intruded not as a whole mass, but rather gradually; the f i n a l result being a composite batholith, which may be regarded as several smaller interlocking batholiths. In Southeastern Alaska the composition varies from Susrtz-diorite in the western part of the Batholith to a quartz- monzonite on the eastern flank, the core being typically grano- diorite. This indicates that successive rook belts from west 31. to east contain increasing amounts of a l k a l i feldspars and quartz, and decreasing amounts of basic constituents. Also, 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 are not at a l l gradual but take place rather abruptly. This feature would tend to suggest the existence of a group of cl o s e l y i n t e r l o c k i n g B a tholiths. # In the A t l i n D i s t r i c t Gairnes reports that a t y p i c a l specimen fro© the eastern border i s on the border-line between a grano-diorite and a quartz-raonzoni te. Dalmage i n describing about 150 miles of the Batholith concluded that there was a tendency f o r the more acid types to l i e along the central part of the B a t h o l i t h . Another feature exhibited by the rocks i s that of a gneiasold character which i s f a i r l y common. This structure, a primary one, was probably formed before and during the process d of consolidation. Two iraportant factors which give r a i s e to t h i s gneissoid character are; (1} the p a r a l l e l o r i e n t a t i o n of the mineral p a r t i c l e s , and (2) the r e l a t i v e segregation of the l i g h t and dark minerals. In addition to t h i s there are also the i n j e c t i o n and reaction gneisses. ^Oalrnes D. D. Geol. Surv. Can. Mem. 37, p. 57 - 59. @ 7. Dalmage, Geol. Surv. Oan. Sum. Rept. 1922, P. 16 A. 4 Buddingtoa, A * P. I . S. Geol. B u l l . 800, p. 238. 3 2 . The Coast Range B a t h o l i t h i s composite not only due to i t s composition bat a l s o due t o d i f f e r e n t times of i n t r u s i o n s . F. km Kerr Says; B 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 composite i n t h a t i t was developed dur i n g .several i n t r u s i v e periods r a t h e r than one." By l o o k i n g at 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 the B a t h o l i t h , i n i t s main p o r t i o n at l e a s t , was Intruded d u r i n g the Upper J u r a s s i c time. And t h i s i s the 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 worked on the eastern contact o f the B a t h o l i t h . However, there are i n d i c a t  i ons 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 intruded # before and a f t e r t h i s n a i n p e r i o d o f i n t r u s i o n . So F. A. Kerr says: "The composite nature 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 that i t s development took plaoe over a long period o f time. G r a n i t i c masses cut P a l a e o z o i c sediments 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 penetrate even tipper cretaceous sediments, fhe b a s a l member o f the J u r a  s s i c a e r i e s contains an abundance o f g r a n i t i c boulders, c l e a r l y i n d i c a t i n g that part of the B a t h o l i t h had been developed and unroofed before that p e r i o d , although tnere nay have been i n t r u s i o n s o f even P a l a e o z o i c age i n t h i s s e c t i o n , i t i s b e l  ieved that development o f the Coast Range B a t h o l i t h proper began e a r l y i n the T r i a s s i c and continued throughout the g r e a t e r part o f the Kesozoic e r a . P o s s i b l y dying-phases-of t h i s igneous a c t i v i t y may have c o n t r i b u t e d i n some small way at even l a t e r # F. A. K e r r , Geol. Surv. Canadian Sum. Rept. 1928, p. 28 33. periods:* l a the map area i t has been p o s s i b l e to separate the B a t h o l i t h i n t o s e c t i o n s that are c l e a r l y of markedly d i f f e r e n t ages, bat there does not appear t o be any systematic arrange ment of these sections.* 1 I t may be pointed out, however, t h a t the oceorrence o f g r a n i t i c boulders and pebbles i n the Lower J u r a s s i c i s not con c l u s i v e evidence i n regard to the time o f the i n t r u s i o n o f the B a t h o l i t h , as the boulders may have e a s i l y come from the o l d mountains o f Cascadia. I t may be w e l l t o remember here that D. D. Cairnes, placed on the same evidence the Laberge s e r i e s , as post i n t r u s  i v e , which 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 to be pre i n v a s i v e , and occupying Lower J u r a a s i c . Much b e t t e r evidence i s a v a i l a b l e , t h a t some p o r t i o n s o f the B a t h o l i t h were intruded i n post J u r a s s i c times. # V. Dolmage s t a t e s : "The age of Goast Range B a t h o l i t h i s not d e f i n i t e l y known. The B a t h o l i t h has been found i n s e v e r a l l o c a l i t i e s to eut the K a z e l t o n f o r m a t i o n which contains Middle 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 i n d i c a t i n g the age o f the B a t h o l i t h to be not e a r l i e r than Upper J u r a s s i c . In the v i c i n i t y of Tatlayoko Lake and In Bridge R i v e r map a r e a , s m a l l B a t h o l i t h s , s i m i l a r i n composition to the Coast Range B a t h o l i t h and s i t u a t e d only a few miles from i t , cut rocks con t a i n i n g Lower Cretaceous f o s s i l s . In Taseko Lake d i s t r i c t what appears to be the main Coast Range B a t h o l i t h cuts 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 coarse, •• fragciental volaanlc rocks i n which the w r i t e r fount. p l a n t remains, determined by .Prof* Edward i l . Berry,, of Johns Hopkins U n i v e r s i t y , to be of Cretaceous age. l a the B e l l a o p o l a — f a t l a area the main B a t h o l i t h iatrudes, a t many places, roeks containing f o s s i l s o f Lower Cretaceous age* This evidence 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 lowest Cretaceous, and the evidence found i n Tatlayoko Lake, Taseko Lake and Bridge l i v e r d i s t r i c t s strongly suggests t h a t much o f the 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 general 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 that as we go north, the Batholith cuts progres s i v e l y 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 seen t h a t i n the south, w i t h the single exception o f Coguihalla and Bridge R i v e r areas, the B a t h o l i t h c a t s Me so zoic r o c k s , from P o r t l a n d Canal norths- wards .Palaeozoics 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 the Yukon, the B a t h o l i t h cuts • Pre-Cambrian r o c k s . • This l a important both-from .physiographic and s t r u c  t u r a l v i e w p o i n t s . As has been mentioned before, the Coast Range Batholith was greatly responsible for formation of ore deposits along i t s contacts, and also for metamorphism of the rocks with which i t came i n contact. In regard to both these points i t i s best to # quote Dr. S. J . Sehofield. # S. J . Sehofield. Ore Deposits of B r i t i s h Columbia, ! Qeol. Surv. Canada, Mem* 132* p. 63. 35. "There are two main mineral belts In B r i t i s h Colombia separated from each other by an elongated and curved area o f granite 3 a t h o l i t h s , belonging mainly to the early part of Me30zoic era. This mass includes the Coast Range Batholith and the majority of the Batholiths occurring i n the southern part of B r i t i s h Colombia. The belt which follows along the P a o i f i c Coast, including the is l a n d fringe on the western aide of 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 side 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 bel t s d i f f e r i n the mineraiogioal composition of 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 for 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 gold, s i l v e r and lead content......" "The reason for the separate occurrence o f copper on the one border and o f gold, s i l v e r , and lead on the other bor der of the great complex of igneous intrusions i s not at once apparent. A fact that may throw some l i g h t on the subject, i s that copper ore deposits are not confined to true f i s s u r e veins, but resemble impregnations of 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 , ohaleoprzrite, which indicate conditions of high temperature and pressure, even bordering on those of contact deposits, whereas the g o l d - s i l v e r and s i l v e r - l e a d depo s i t s are usually, though not always, associated with fissure veins f i l l e d under conditions o f a moderate temperature and pressure, the g o l d - s i l v e r being characterized by the presence of such minerals as gold, s i l v e r , argentite, pyrargyrite, etc., i n a quartz gangue and the s i l Y e r - l e a d by galena, zinc blende, 36. t e t r a h e d r l t a i n a gangus of a a l c i t e , s i d e r i t e and sometimes q u a r t z . . . . . . . " "Hot only i s there a c o n t r a s t between the ore depos i t s on the two aides o f these 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 explanation f o r the f a c t s c i t e d above: " I t i s w e l l known that 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 the aa««snding hot s o l u t i o n s from the u n d e r l y i n g molten magna* On the other hand the deeper and more v e r t i c a l contacts do not show contact matauorphiso to the same degree not only as regards i n t e n s i t y but a l s o as regards u r e a l a x t e n t . I f the B a t h o l i t h and the intruded rocks are exposed i n a plane normal to the v e r t i c a l plane o f the B a t h o l i t h , the plane would c o n s i s t o f a core o f g r a n i t e sur rounded by a contact zone o f approximately the same width. On the other hand, i f the B a t h o l i t h and the i n t r u d e d rocks are cut o b l i q u e l y , the r o o f roeka w i l l be preserved higher up on the low s i d e , whereas on the high s i d e the h i g h l y metamorphosed r o o f rocks w i l l be e n t i r e l y removed and the con 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 contact metamor- phi o zone w i l l be very narrow on the high side and very wide and I r r e g u l a r on the low s i d e . In 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 h i g h s i d e w i l l be almost f r e e from them. Examination shows that the two s i d e s o f the Coast Range B a t h o l i t h correspond 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 : 3 7 . Baatern Flank. 1. Smooth f l o w i n g c o n t a c t . 2. Few r o o f pendants. 3 * ¥©ry•narrow metamorphlo sone. 4. S l a t e s , sandstones & t u f f s e h a x a c t e r i s t i c . 5. Moderate temp, c o n d i t i o n s . 6. G o l d - s i l v e r and s i l v e r - l e a d d e p o s i t s o f medium tempera ture and pressure. 7. Intruded rooks o f r o o f type, gneisses and s c h i s t s reach the saiae e l e v a t i o n as the u n a l t e r e d r o c k s along the s t e e p l y p i t c h i n g contact» "These f a c t s show that e r o s i o n on the western 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 that the contact between the B a t h o l i t h and these 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 the presence o f a l a r g e number o f r o o f pendants and the very i r r i g - u l a r contact between the 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, erosion 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 being e n t i r e l y removed, so t h a t the margin of the B a t h o l i t h plunges very s t e e p l y beneath the Intruded rooks. A l s o , the contact i s smoothly u n d u l a t i n g and the r o o f pendants are absent. This 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 eastern Western Flank. 1. ¥ery I r r e g u l a r contact 2 . Many r o o f pendants. 3 . Wide metamorphic zone. 4. S c h i s t s and gneisses c h a r a c t e r i s t i c . 5. High temp, c o n d i t i o n s . 6 . Copper d e p o s i t s of high temperature and pressure. Description of Formations. Pre-G'anbrlan. The oldest rocks along the eastern contact of the Coast Range Bathollfcft are found In the . i l a h i h i k Lake, the Tnitehorse d i s t r i c t and the A t l i n d i s t r i c t . 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 Cairnea as probably Pre* Cumbrian i n age. The Yukon group of 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 both sedimentary and igneous types, and represent probably d i f f e r e n t ages within the Pre-Cambrian, but they have been so h i g h l y metamorphosed t h a t In many cases 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 consequently, to determine t h e i r h i s t o r y . The group i s represented by mica s c h i s t , quartz- mica s c h i s t , c h l o r i t e s c h i s t , granite gneiss, and c r y s t a l l i n e l imestone. This group forms, Tor the greater part o f the area, the rocks into which the Coast Range S a t n o l i t h was i n t r u d e d , and, therefore, the degree o f netaaorphlsm i s high. The lioant Stevens group Includes a number of aeubers widely d i f f e r e n t In appearance, composition, and possibly i n age. They are, however, a l l old and ao extremely altered that t h e i r mode of o r i g i n and succession are obscured. They c o n s i s t of 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 rtzites, gneissoid 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. # Cairnes D. D. G. S. C. Mem. 67, p. 40 - 44 40. Ho f o s s i l s have been col l e c t e d froea any of the members of the Mount Stevens group and there i s consequently no dir e c t evidence as to 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 probability the oldest rooks i n the d i s t r i c t . Cairnea^ i n hi a l a t e r work along the i n t e r n a t i o n a l boundary, north of Yukon r i v e r , ;/as able t o demonstrate that the schistose rocks of that 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 of rocks, occurring i n the S'hitehorse and A t l l a d i s t r i c t , the gold series and the Taku group have been pr o v i s i o n a l l y assigned to the Devonian. The Gold series occurs i n two r e l a t i v e l y small 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 ridge ju s t north of 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 of 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 of the Batholith i n t n i s d i s t r i c t and i s characterised by reddish-brown weathering of i t s rooks whioh make i t most conspicuous. The rocks of t h i s series also occur i n the A t l i n d i s t r i c t , and a description of them Is given i n Part I I I , on A t l i n d i s t r i c t . ( # e Gairnes propoaed the name Taku for a series of charts, slates and cherty q u a r t z i t e s , which have been referred to the # Gairnes, D. D. G. S. C. Mem. 37, p. 52 - 55. Gwillim, J . G. G. 3. 0. An. Rept. Vol. H I * 4 1 . Cache Creek group of the 30 at ham 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 these rooks occur p r i n c i p a  l l y In the v i c i n i t y of Tagish l a k e . The nembers o f the s e r i e s grade into o.no another, and, In places, are such f o l d e d and d i s t u r b e d * file3e rocks underlie limestones which are probably Carboniferous i n age, and, therefore, have been considered as Devonian In age. • Another group of rocks, which n i g h t be grouped as Devonian, outcrop i n the Stikine River area. This group i s c o n s i d e r a b l y folded and aetataorphosed and consists of a great thickness of s l a t e s , s c h i s t s , quartettes, and limestones. Kerr i n h i s description does not d e f i n i t e l y put i n the Devonian but merely places i t as older than Persian. Carbonlferoua. The Carboniferous rooks occur i n the northern section 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 In the a t l i n D i s t r i c t . In the south they occur In the Bridge River area and the Co 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 Rivers 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 possibly be classed as Carboniferous i n age. An Important member of the Carboniferous rocks has been ca l l e d the Braeburn Limestones. This name was f i r s t applied i n the Braeburn-iCynocks area by D. D.Cairnes , i n mem.5 of the O.3.C. 4 2 . These Hetest'onea occupy a large area i n the v i c i n i t y of Tsfcu Am, iTInfly- HI ?©r, and Tagish Bake of the A t l i n and Whitehoroe d i s t r i c t s . S'heee limestones are generally f i n e l y textured and range In colour from /greyish blue to almost white. l!r» .Dawson coll e c t e d F u s i l i n a e from the limestones which extend 'along the east side of Windy Are, showing these belts at le a s t to be Carboniferous, so the whole series ts. thought probably to belong to t h i s age, although no other fos s i l remains of a d e f i n i t e character have been discovered. The Carboniferous ©embers which occur i n the southern section of the area under consideration appear i n the Bridge Elver and Coguihalla areas. The Bridge River series comprises nearly seventy-five percent of the rocks o f the map area. This series estimated to be about 9*500 feet t h i c k , i s composed mainly of contorted, thin-bedded cherty quartzites separated by thin films of a r g i l - l i t e s c h i s t , dark, coloured altered a g r l l l i t e s , c r y s t a l l i n e lineotone lenses, and arenaceous s c h i s t s ; flows of black and green metabasalt. In the v i c i n i t y of the in 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 , talcose, s e r i c i t i c and c h l o r i t e s c h i s t s . The Coguihalla 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 greatly i n thei r mode of o r i g i n . These types are volcanic greenstones, cherts, and fine grained, argillaceous and calcareous sediments. The greenstones are 43. composed,for the most part, of andesitio lava flows which con t 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 sediments are generally so intimately Interbedded that a d e f i n i t e d i v i s i o n i s not feasable. The thickness of these rocks by G. E. C a i r n e s , i s about 16,000 feet, 11,000 of which i s composed of green stones, and the remainder of cherts and other sedimentary rocks. A considerable portion of the area occupied by these rocks has been partly concealed by younger rocks. # C a i r n e s , C. E. Mem. 139. Permian. Kerr, i n summary r e p o r t s f o r 1928 and 19H9, describes limestones In the S t i k i n e and Iskut R i v e r s areas, which he places i n the Permian. These are the only Permian rocks occur r i n g a l o n g the eastern contact of the Coast Range.Batholith. ? r l a s s i e . The T r l a s s l o l a represented i n the S t i k i n e and Iskut R i v e r s a r e a , i n the Chilko Lake and the Bridge R i v e r d i s t r i c t s by the Oadwallader s e r i e s and i n the C o q u i h a l l a area by the Tulaaieen group. The rocks i n the S t i k i n e and Iskut R i v e r s area, accord i n g to K e r r , are a r g t l l i t e a , s l a t e s , limestones, coarse b r e c c i a s and conglomerates, and volcauiea. This a c r i e j i3 cat by the Coast Range B a t h o l i t h . The Oadwallader a e r i e s occurs as a narrow b e l t along the western part o f the Bridge R i v e r nap area. 44. I t has a t o t a l thickness of 2,100 feet, and i s com prised of great thickness of b a s a l t i c and andesitic greenstone, conglomerate, sandstone and shales with subordinate thin-bedded limestones and dolomite. A series of rocks occur i n the C h l l - ko Lake d i s t r i c t are'very s i m i l a r to the Cadwallader series and can be correlated to them. The Tulameen group of the Coquihalla area comprise a large part of the nap area In the southeastern section and also a small o o r t i o n i n the extreme northern end. Primarily they are composed o f sediments and v o l c a n i c r o c k s . The former are p r i n c i p a l l y gray or black s l a t e s , which inc l u d e a few t h i n limy beds, fhe v o l c a n i c rocks form the bulk of the group and are commonly dark green, and i n c l u d e a c h i s t o s e , as w e l l as massive v a r i e t i e s . .Alteration has progressed f a r i n a l l the a c n i s t o s e Volcanic r o c k s , and, to a l e s s e x t e n t , i n the more massive types. The 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 of t n i s series i s a crushed granite porphyry occurring as b e l t s o f s i l l s up to & several yards i n width. # ¥. BoImage, C h l l k o Lake and V i c i n i t y . Sum. Rept. 1924. I J u r a s s i c . ' Jurassic was a very Important period i n B r i t i s h Colum b i a . Great thicknesses of sedimentary rocks v,-ere deposited i n a l a r g e b a s i n of sedimentation, that once occupied the whole of B r i t i s h Columbia and Alberta aud extended at l e a s t as far east as t-oosejaw. 45. f o l c a n i s m was a l s o a c t i v e ; bat the most important event from the viewpoint o f economic geology was the i n t r u s i o n of the great Coast Range B a t h o l i t h . As t h i s event was o f paramount Importance to formation 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 escribed under a separate heading. 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 probably represented by a group o f rocks known as the o l d e r v o l c a n i c s which c o n s i s t o f green to red a a d e s i t i c rocks 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 are found to be younger than the Yukon group o f v/hltehorse d i s t r i c t and, as they are ©at by the g r a n i t i c i n t r u s i v e s wher ever the two come i n contact they are probably 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 n t r u s  i v e i n t o the Laberge beds, and nay therefore be considered younger. C o c k f i e i d c o n s i d e r s them to be Lower or Middle Juras s i c . The ;7hlte horse and A t l i n d i s t r i c t s are represented here by the Laberge s e r i e s , the Tantalus conglomerates, and the o l d e r v o l c a n i c s . The Laberge s c r i e s I s the nost extensive g e o l o g i c a l terrane i n Taku Area b e l t , and i t s nemberc outcrop i n a general way throughout the c e n t r a l , southwestern and northwestern por t i o n s o f the d i s t r i c t . The group of h i l l s east of Taku area and south of Graham I n l e t ; the g r e a t e r part of the area north o f P a n t a i l Lake and south o f Tutshl Lake, on the west side of Taku area; and Sunday Mountain and the western 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 rocks. 46. The Tantalus conglomerates are probably best i n c l u d e d w i t h the Laberge s e r i e s , because tney o v e r l i e the Laberge rocks conformably. I n $aeaton d i s t r i c t , where the most d e t a i l e d work done i n the d i s t r i c t was undertaken, and where the best exposures of # t y p i c a l l y marine sediments occur, Calrnes recognized a three f o l d d i v i s i o n o f the Laberge beds, as f o l l o w s , or i f , as i n the -present case, the Tantalus conglomerate be i n c l u d e d , a f o u r f o l d d i v i s i o n : — Tantalus Conglomerate:— Thickness 1,800 f t . Conglomerate, s h a l e , sandstone, and c o a l . Laberge S e r i e s : - - IJpper b e d s — — t h i c k n e s s 1,500 f t . sandstone 1,'lddle b e d s — n 1,700 f t . shales,s.s. ,arkose. Lower b e d s - — 1,800 f t . arkoee and t u f f s . t o t a l 6,000 f t . F o l l o w i n g c o c k f i e l d j — " F o s s i l s have been collected from the Laberge beds i n 3'neatoii, 4 t l i n , './hltehorae and Tantalus areas. In the c o l l e c  tions- from Tantalus area, three 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, Iferinea aaudeneais, and Hhfnchon- e l l a o r f c h i d i o i d e s . r?he specimens were regarded by tfhiteaves as J u r a s s i c or Cretaceous but two i f not a l l three of these species arc now regarded as Jurassic forma. Cairnes D. D., Wheat on D l s t r . O.S.O. Mem. 31, 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 reported on by Stanton as follows: "these may p o s s i b l y be T r i a s s i e , bat I think i t more probable that they are e a r l y J u r a s s i c * They are c e r t a i n l y not as l a t e as the Cretaceous."# "Thus i t appears to be very w e l l established that the Laberge beds range i n age from Middle Lower J u r a s s i c t o Lower Middle J u r a s s i c . " The older volcanics 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 in t r u s i v e a and are s i m i l a r i n character to, those found In the Alahlhik 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 River formation, a volcanic member which Is over £,000 feet i n tnickness and c o n s i s t s for the most part o f agglomerates 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 , consists mainly o f f i n e conglomerate bearing pebbles o f the underlying volcanic neraoer and l i e s conformably between the Bear River formation and the Haas formation. The itass fo mat Ion consists mainly of 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 elearage esp e c i a l l y as the contact of the Coast Range Batholith Is approached. The t h i c k  ness of t h i s formation i s thought to be s l i g h t l y wore than 1,000 feet. Intruded along the bedding plane o f the t u f f s o f the Bear River formation are s i l l s of grano-diorite porphyry, # Swillim, T. C G. S. C. Ann. Rept. . I l l , p t . 3, p. 23 - 27. ## 1. E. Cockfieid & A . R. B e l l , G.S.C. J'em. 150, p.H£. 48. v a r y i n g In t h i c k n e s s , bat i n no case sore than 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 on the d i s t r i c t say "The name Premier s i l l s i s g i v e n to a s e r i e s o f t a b u l a r igneous bodies t h a t were in t r u d e d along the bedding planes o f the t u f f s o f the Sear R i v e r f o r m a t i o n , when these t u f f s were i n h o r i z o n  t a l p o s i t i o n . L a t e r 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 present p o s i t i o n and were subsequently exposed by e r r o s i o n . " The area between Skeena and Stewart and a l s o the JSutsak Lake d i s t r i c t are represented In the J u r a s s i c by the Kazelton group. The rocks: here are 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 , and have been d i v i d e d Into four formations: The lower v o l c a n i c d i v i s i o n c o n s i s t s of f i n e g r a i n e d , i v e l l - s t r a t i f i e d , red t u f f s 500 feet t h i c k l y i n g conformably below marine sediments. Below these red t u f f s there i s about 4,000 f e e t o f a n d e s i t i c t u f f s , b r e c c i a s and l a v a flows. The_ K i d d l e sedimentary 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 fee t t h i c k . This 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 evidence gathered from i t places 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 flows and t h i c k massive beds o f coarse b r e c c i a , a l l o f an a n d e s i t i c nature, and v a r i e s in- thickness from 2,000 - 3,000 f e e t . The Upper sedimentary beds, which are about 1 ,000 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 conglomerate. S c h o f i e l l 3. J . and Hanson, 0. Mem. 1'6'd, p* 21. 49. Setae of the middle strate hold several coal seams. :Pre-batholitic rocks of Jurassic age are absent from the Chllco Lake d i s t r i c t but occur again In the Bridge River area and In the Coguihalla d i s t r i c t . fh© occurrence in. the Bridge River area i s In 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 Cadwallader series and forms the c h i e f country rock of the gold-quartz veins i n the region. fhe Ladner group of rocks are the dominant rooks of the J u r a s s i c . I n the Oojuihalla area and they may be divided i n t o two groups. The lower group which occupies over ninety percent of the area covered by the aeries, i s composed c h i e f l y of s l a t y rocks, and Is known i n that d i s t r i c t a "slate b e l t . " The upper group Is conformable with the rocks of the slate belt and i s composed of conglomerates, tuffaeeous greywaekes, and an equal proportion of more s l a t y rocks. The rocks which have been under discussion 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 Porphyrite group of Dawson, and as they contain the r i c h gold aad s i l v e r deposits of the eastern contact b e l t , a great deal of work has boon dene on co r r e l a t i n g them to Dawson's f Porphyrite group which he defined In 1875 as follows: "Thin name nay be pr o v i s i o n a l l y employed to designate a series of rocks, c h i e f l y feldspathic and often p o r p h y r l t i c , though also including d i o r i t e s of varied texture, the reference of which to any of the groups formerly defined, seems uncertain. Dawso.i, Q, M. G.3.C. Dept. of Progress 1875-76, p. £50. 50* They are heat seen about Tatlayoco Lake, where they o v e r l i e unoomforaably the Cascade C r y s t a l l i n e rooks, and appear to u n d e r l i e the beds o f the Jackass Mountain s e r i e s . The whole o f the r o c k s o f t h i s group seems to be made up o f igneous o r i g i n , though some o f them may owe the .arrangement of 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 of a number of f a c t s con c 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 f a c t s . {1} "The areas where the f o s s i l evidence concerning the age o f the P o r p h y r i t e group i s most complete are those described by Dawson In the v i c i n i t y o f Tatlayoko Lake and by Malloch i n the groundhog c o a l f i e l d , and i n both cases a J u r a s s i c age i s i n d i c a t e d . ' (2) l o evidence lav submitted by any o f the workers o f a s t r u c  t u r a l unconformity between the P o r p h y r i t e group and the over l y i n g Skeena s e r i e s , which i s Koofcenay i n age, although i n many places a heavy conglomerate c o n t a i n i n g pebbles o f tne under l y i n g P o r p h y r i t e -group marks the, base of the Skeena s e r i e s . (3) The r o r p h y r i t e group i n the v i c i n i t y of tne Coast Hang© B a t h o l i t h contains a great t h i c k n e s s of a n d e s i t l c and aadeait© ft b r a c c i a which i n the oast gives -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 shales 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 pointe to a l i n e a r source o f supply f o r the P o r p h y r i t e group i n the area now occupied 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. 132, 0.3.C. J?. 20. 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 Jurassic and the Cretaceous i s substantiated to some extent. (5) The grano-dlorite of the Coast Range proper cuts the Por phyrite group, and pebbles of 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 series o f northern B r i t i s h Columbia and the Yukon . fhe presence of 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 of 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 of o the Coast Eange Bat h o l i t h as p a s t - P o r p h y r i t e group and pre- Lower Cretaceous; t h e r e f o r e . In very l a t e Upper Jurassic time. Hence the Porphyrite group must be older than the Lower Creta ceous 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 of these sedimentary and volcanic beds with the Porphyrite group and also t h e i r r e l a t i o n to the Coast Range Bat h o l i t h . fhe Post B a t h o l i t h ! c rooks are of comparatively l i t t l e importance to econctaic geologist, since tne great majority o f ore deposits are connected with the i n t r u s i o n o f Coast Range Batholith and i t s s a t e l l i t e s . However, for the sake o f com pleteness, I t was deemed advisable to neat ion the i-oat-Batholi- taic--Cretaceous and T e r t i a r y deposits. i • 'Dawson,' S. M., 0.3.0- Sua. Hept. Vol. H I 1896, p . 147 - 156. Gairnaa, D. B ., 0. i . 0» .Meat. 31, 191L. 5<2» Cretaceous. Upper Cretaceous rocks ooour i n the S t i k i n e and Iskut Rivers, a r e a , these rooks are mostly conglomerate and sandstone w i t h a t h i n l a y e r of v o l c a n i c s on top. In the Salmon r i v e r area, Laiiprophyro dykes are considered to be lower Cretaceous i n age. An area of p o s t - b a t h o l i t h i c Cretaceous rocks l a found near Skeeaa R i v e r , and i s known as the Skeena formation. This formation c o n s i s t s o f a r g i l l i t e s , sandstones, shales and con glomerate w i t h pebbles o f ^ r a n c - d l o r i t e . In the T a t l a B e l l a Coola and C h i l c o Lake areas, the Lower Cretaceous sedlaents are considered by Dolmage to be P r e - b a t h o l i t h i e and eons l o t of sandstones, conglomerates, arg i l l i t e s and b r e c c i a . F a r t h e r south the Cretaceous rocks are represented by v o l c a n i c s , mostly p y r o c l a s t i e s and some andesite tf and b a s a l t . These v o l c a n i c s are cat by Coast Range I n t r u s i v e s , c o n s i s t i n g of g r a n i t e , q u a r t z momsonite, d i o r i t e , quartz- d i o r i t o , e t c . The i n t r u s i v e s are placed as Upper Cretaceous.^ $ lien. 130. G. 3. C and Sum. Rept. for 1928.. T e r t i a r y . The T e r t i a r y i n B r i t i s h Columbia was a period o f great v o l c a n i c 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 are extensive flows of 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 are both of the A c i d and Basic type; according to $he present know ledge of the area the a c i d v o l c a n i c s are more important i n the north; i n the south beginning w i t h Sutsuk Lake and f u r t h e r to the south the flows aro 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 observed on the included t a b l e o f formations. Quaternary. The Quaternary w i t h the exception 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 represented by g l a c i a l and f l u v i a l d e p o s i t s o f muds, t i l l s , and g r a v e l s . The deposits are s c a t t e r e d a l l over B r i t i s h Columbia, p a r t i c u l a r l y In r i v e r v a l l e y s and Lake f l a t s . LL Soonomie geology*. In describing the economic geology of the eastern con tact o f the Coast Range Batholith i t was considered best to s t a r t frora the north, 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 des cribed i n greater 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 properties, but rather compile the geology, .and thus present a more g e n e r a l i z e d description of the eastern contact. Unfortunately, i n the available l i t e r a t u r e , the geology Is treated only l o c a l l y , very often In r e l a t i o n to a single group of c l a i m s , and so considerable amount of work, was necessary to separate the geologically Interesting and important facts from such i r r e l e v a n t facts as number of claims, c a p i t a l i z a t i o n , etc. I t was also decided to pay-more attention to the producing, or producing i n the past, oroperties,' and pass over the s i a a l l prospect c l a i m s , so as not to overload t h i s essay with apparent and not '.veil established facts- One of tne moat i n t e r e s t i n g ore deposits i n the north 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 plateau. The h i l l s are p r e v a i l i n g l y f l a t topped and separated by broad deep • a l l e y s . <Ceno H i l l l a a t y p i c a l wedge-shaped ridgo, l y i n g between Lightning, 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, of 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%/ * are 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 of granite porphyry and quartz porphyry. 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 intruding t h i s schist series are them selves l a r g e l y sheared and a l t e r e d . The quartz and granite porphyries are massive and fresh i n appearance and are believed to be offshoots from a granite mass which outcrops some mil e s to the east, and which probably extends under a cons i d e r a b l e part of Mayo d i s t r i c t . The qua r t z i t e , quartz-mica 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 to the Ifacina s e r i e s , described by HeConnell i n his report on Klondike d i s t r i c t . This series has been referred by Cairnes to the Pre-Cambrian. The ore deposits 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 deposited i n f a u l t f i s s u r e s . The fa u l t s which gave r i s e to these veins are a l l o f normal type, and t h i s - applies also to p o a t - o i a e r a l f a u l t s . fhe 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 verse, depending on whether they follow the'trend of 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 consists of quartz, arseno- pyrlte and p y r i t e . After being f i l l e d , the l o n g i t u d i n a l f i s s  ures -remained planes of weakness affected by subsequent move ments* When the transverse .fissures 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 for the ore bearing solutions and considerable amounts of the ore minerals were deposited i n them. The c h i e f minerals of the second stage are s l d o r i t e , f r e i b s r g i t e , galena and sphalerite. The f o l l o w i n g minerals rfere i d e n t i f i e d froca the Keno H i l l deposits. Eatlve elements- -Silver. Sulohldes 3 u l p h o - s a l t s Oxides Carbonates Sulphates -ryrargyrite» f r e i b s r g i t e , —Argent!to, galena, s p h a l e r i t e , c o v e l l i t e , c h a l o o p y r i t e , p y r i t e , a r s e n o p y r i t e . polybaai t e , ^amesonite. — - i u a r t z , l i m o n i t e , manganite. — S I d e r i t e , c o a l c i t e , c e r u s s i t e , raaiaofclte, a z u r i to — B a r i t e . Genesla. By f a r the gr e a t e r muuber o f veins on Keno H i l l r e p r e  sent a simple f i l l i n g of fa u l t f i s s u r e s . Replacement of wall rock operated only to a a l i g h t extent, except In tne Sadie- ,freadwell v e i n . The ore minerals i n most cases are fa s t e n e d to the p o l i s h e d walls of the f a u l t f i s s u r e s , but do not project 5 7 . I n t o theta. I t i s not believed, however, t h a t at the time o f m i n e r a l i z a t i o n the f a u l t s existed as open fissures 4 to 6, or more, feet wide, but rather that the small openings formed by the f a u l t s grew'in width as the ore~ minerals were deposited. I t has been demonstrated that the 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, active, o r whether the force exerted by 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 to open the f i s s u r e s , i s unknown. In certain cases there i s evidence of solution of w a l l - rock. This i s shown in Ho. 9 vein of Keno H i l l , Limited, where large, drusy c a v i t i e s l i n e d w i t h crystals of s i d e r i t e and g a l  ena occur i n the Toot w a l l . Replacement of wall-rock In the Ssdie-Treadwell vein, presents many characters not exhibited In the other veins o f the area. This v e i n , or 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 re-unites, with c r o s s - f a u l t s between the eaain f r a c t u r e s . The country rook ir. the v i c i n i t y was badly shattered and the ,loInt Jn£ emphasized, a ad the ore-hearing s c i at ions pene trated each rainate creek, widening I t , and, In p l a c e s , r e p l a c i n g the country rock. In places the mineral zone if. a network o f tiny v e i n l e t s o f a t d e r l t e enclosing fragments of country rock. Ae a r a l e these fragments l i e In t h e i r o r i g i n a l positions, but in certain instances the p a r t i c l e s o f rock -were rotated. These v e i n l e t s represent on a s n a i l scale what has taken place on a large scale. Telns of o r e project out Into the country rock, 58. i n maay eases at right angles t o the main trend o f the ore zone. Examination o f t h i n s e c t i o n s has shown t h a t t h e s e v e i n s grew by replacement o f the c o u n t r y r o c k . Fragments o f quart- 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 f e l d s p a r are included i n s i d e r i t e . I n some cases, 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 s i d e r i t e p r o j e c t i n g i n t o them. I t l a consequently b e l i e v e d t h a t the Sadie-Treadwell ore gone r e p r e s e n t s a 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 Minerals were i e p o a i t e d , and by r e p l a c e m e n t . 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 i n Keno H i l l a r e a t r a v e r s e q u a r t z i t e s c h i s t s and g r e e n s t o n e a l i k e . The greenstones tauiit, t n e r e f o r e , have been c o n s o l i d a t e d s u f f i c i e n t l y to p e r m i t o f f r a c t u r i n g a t or before the time o f m i n e r a l i z a t i o n . Moreover, the greenstone bodies by r e a s o n o f t h e i r s m a l l s i z e would be u n l i k e l y to h o l d s o l u t i o n s f o r long p e r i o d s , p a r t i c u l a r l y a f t e r the development o f the f a u l t s . She aeid dykes c a r r y s m a l l amounts of galena, p y r i t e , and t e t r a h e d r i t e . As t h e s e v/ere not i n j e c t e d u n t i l l o n g a f t e r th© g r e e n s t o n e s -./ere c o n s o l i d a t e d , and even s h e a r e d , I t i s d o u b t f u l i f the g r e e n s t o n e s had any e f f e c t on t h e i r min e r a l i z a t i o n . Th© presence o f c e r t a i n o f t h e ore M i n e r a l s i n the quartz and 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 may have been the source of the ore d e p o s i t s . I t i s not t h o u g h t , however, t h a t t h e s e 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 the 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 and 5 9 . the m i n e r a l i z i n g e o l a t i o n s had t h e i r o r i g i n i n a l a r g e r body o f magfaa* A l a r g e mass o f g r a n i t e ooeurs to. tne e a s t o f Keno H i l l , and o t h e r nasaes occur 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 and southeast* I t i s probable that t h e s e r e p r e s e n t the peaks of a B a t h o l i t h w h i c h extends under, much o f Mayo a r e a , f h e age o f t h e s e g r a n i t e s has n o t been c l o s e l y determined, owing to t h e l a c k o f 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 w i t h the Coast Range i n t r u s i v e a which i n Yukon range from J u r a s s i c to Upper C r e t a c e o u s . The ore d e p o s i t s are y o u n g e r , but cannot 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 to age. • fh. 1 tehorse D i s t r i c t . A l l known ore d e p o s i t s o f -tffcitehorae d i s t r i c t have p r o b a b l y foraed l a t e r t h a n the I n t r u s i o n of the Coast .iange B a t h o l i t h . T h i s I n t r u s i o n p r o b a b l y t o o k p l a c e i n l a t e J u r a s s i c t l a e and p o s s i b l y c o n t i n u e d t h r o u g h a p a r t o f L e e r C r e t a c e o u s t i m e . Two c o n t r a c t i n g types o f 'deposits o c c u r , — contact jaetamorphic and hydro t h e r m a l • McCoimell, li* G. "Whitehorae Copper 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. 51, 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. Trans, v o l • ..iVIII, i?« b3, 1915.) tf. S. C o c k f i e i d and A. H. B e l l . Geol. ourv. Canada, Kern. 150) } "W'hi tehorae D i s t r i c t , Yukon." ) CO. . C l a s s i f i c a t i o n of Deposits. Deposit. Occurrence Mineral a s s o c i a t i o n . Antiraony I n Coast Mange Intrusive Gangue c h i e f l y S i l v e r rocks and i n Chieftain 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 breccias. O t i b n i t e , s phalerite. Jameson!te, arseno- pyri te, tetrahedrlte. Chiefly i n Coast Range wiar t z, c a l c i t e , I n t r u s i v e 3 , also i n galena, p y r i t e , Gold-Silver schists of Kount Stevens chaleopyrite, gold $N>up. Occur as f i s s u r e s y l v a i i i t e . f i l l i n g s . In Laberge rocks, as Quartz, c a l c i t e , S i l v e r - raetasoaatic replace galena, a r s e n o p y r i t e , Lead ments, geodea and sphal e r i t e , p y r i t e , vu^s common. chaleopyrite. At contact o f Coast Magnetite, specular!te Contact- Range Intrusivea with chaleopyrite, quartz, Met amorphic. country rock, 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, w o l l a s t o n i t e , llmonlte, a z u r i t e , malachite occur i n oxidized zone. 6 1 . .fho -contact aetamorphio d e p o s i t s . are c h i e f l y confined to a narrow be l t about 15 mile a long, p a r a l l e l to Lewes r i v e r i n the v i c i n i t y of "Jhitehorse. The larger aggregates of m e t a l l i c minerals occur i n limestone or along the contact of limestone and g r a n i t i c rocks., but numerous small bodies and s c a t t e r e d g r a i n s are found wholly enclosed i n granite and many are at a considerable distance from th© limestone. The development o f n o n - m e t a l l i c minerals i f probably g r e a t e r i n tne g r a n i t e than in. the li m e s t o n e , and the areas a f f e c t e d are wider and more ex tensive. . In -places the o r i g i n a l contact i a completely obscured owing to the replacement o f both rocks by s i m i l a r minerals.-The .extensive and simultaneous m i n e r a l i s a t i o n of both the intruding and intruded rock say be explained by assuming that i t was effected 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 to 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 with the main granite area i s a l s o s i g n i f i c a n t i n t h i s connection. 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 limestone were noted by .Dr. w. K. Cockfield at various p o i n t s i n the eastern 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 of m e t a l l i c minerals i n evidence, fhe only other ore deposit of t h i s type known i n the area Is that situated cn the Fleming claim in frieaton d i s t r i c t , fhe ore materials occur i n hornblende gneisses of tne L'ount Stevena group {possibly of 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 that there has been a period o f mineralization i n vJMtefcorsc d i s t r i c t c losely f o l -6 8 . lowing the i n t r u s i o n of the Coast Range g r a n o - d i o r i t e n . Ores of 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 conditions of high teciperature and high pressure and i n t h i s respect contract strongly w i t h other types of ore deposits i n the region. The available evidence points to a l a t e Juras s i c or early Cretaceous age for the i n t r u s i o n of the grauo-dio- r i t o , and hence i t nay be concluded that t h i s f i r s t caetallc- • genio epoch also belongs i n the Upper Jurassic. The ore deposits o f V/hl tenor se d i s t r i c t , other than the contact rsetaaorphic d e p o s i t s , have teen c l a s s i f i e d by cairnes into three d i v i s i o n s , g e l d - s i l v e r , anttsiony-silver, and s i l v e r - lead v e i n s . Of these, the- f i r s t clase i s "of 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 portion o f the ore d e p o s i t s , not only of ;/heatoja d i s t r i c t but a l s o c f .Vlady area d i s t r i c t tc the southeast." The genesis o f these t h r e e types c f vein deposits has 'been discussed by Cairnes i n his memoir on the #<heaton d i s t r i c t . The conclusions reached are.; (1) That they have a l l been deposited .by ascending hydrothermal .solutions 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 deposited under c o n d i t i o n s of r e l a t i v e l y lov# tempera ture and pressure. These concilia!ona are bused on: (1) n i n e r a l a s s o c i a t  i o n s ; and {2) the fact that the w a l l - r o c k Is altered only s l i g h t l y . From the evidence so far accumulated tae exact geolo g i c a l age of the format ion of tho throe types of vein deposits cannot be d e f i n i t e l y determined* That they are o f co n s i d e r a b l y l a t e r age than the contact joetaraorpiiic d e p o s i t s seems to be i n l i t t l e doubt. They are younger than the period o f s o l i d i f i c a  t i o n of at least a pr.rt of the g r a n i t i c magma, and they ante date the e r u p t i o n s grouped under the head of Hewer v o l o a n i c s . This evidence tends to she?; a la t e J u r a s s i c to e a r l y t e r t i a r y age for these deposits, and depends upon tne length of time r e  quired for the cooling and s o l i d i f i c a t i o n of the Ba t h o l i t h . That the i n t e r i o r of the B a t h o l i t h remained i n a heated and f e r  t i l e condition for a co n s i d e r a b l e period of time there can be l i t t l e doubt. The three d i f f e r e n t types nay or nay not be con temporaneous; a simultaneous o r i g i n can v*ell be presumed by as 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 par ent magma, a case o f magmatic Hegregacion. The d i s t r i b u t i o n o f ore deposits 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 that they are a l l close to the bor ders o f areas of g r a n i t i c rocks. This f a c t should be borne i n mind i n f u t u r e prospocting ©ork i n .fnitehorse d i s t r i c t . F arther south on the other aide of tne p r o v i n c i a l boun dary, 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 arc treated i n considerable d e t a i l i n Pa r t I I I o f t h i s paper, we w i l l pass over i t at present. I t may be well to say at 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 of A t l i n and t/hitenorse d i s t r i c t s . Taia i s no doubt due to the great s i m i l a r i t y of the general geology of the two d i s t r i c t s . 64. Taku It 1 ver iAre a. 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 o f reconaissanee work.. 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 gran o - d i o r i t e b a t h o l i t i e rocks c o n s t i  t u t e the bulk of the loader urea of Taku Ri ver, fro a i t s south to v.-ithin b wiles 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 northerly d i r e c t i o n , and apparently follows t h i s course about 6 a i i e s west of the Tulaeguah River. The roeka eaat of the contact c o n s i s t mainly of tiv* older Igneous groups, probably T r i a a a i c or J u r a s s i c , with some lltae stone and altered sed 1 me a tar i ca. This oerlaa ia iatruled- by youager r h y o l l t e , dacite, and f e l - a i t c dykes aad s i l l s which In turn arc intruded by basic rocks of lamprophyro typo. Folding and evidence of acute stress i s observed near the c o n t a c t west o f the International boundary. Easterly t h i s condition i s gradually s'dniaized, una the structure, A e l l def ined i n certain l o c a l i t i e s , assumes the more stable and d e f i n i t e character that would bo conducive to the confined c i r c u l a t i o n of mineralizing solutions and the deposition of sustained ore- bodies. Taku HI ver D i s t r i c t , 3. 0. ?• A. Kerr, b'uai. kept. 12 £2. Taku R i v e r ..rea, J . T. Tfandy, M l n l s t . o f i'.lues, Rept. 1929, P. C. 133. 65. F a j o r f r a c t u r i n g , aooomnatiled i n places by w e l l - d e f i n e d shearing, has occurred along both a n o r t h - e a s t e r l y and a north westerly d i r e c t i o n . 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 to 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 sulphides c a r r y i n g a p p r e c i a b l e gold and s i l v e r values 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 copper, lead and z i n c , but c a r r y i n g decided g o l d values, and p r a c t i c a l l y n e g l i g i b l e s i l v e r contents i n a quartz ganga*. Ore-Bodlea o f Type 1. The Tulseguah and K a n v i l l e ore bodies belong to t h i s type. These occurrences are c h a r a c t e r i s t i c replacement ore- bodies In shear-zones. In 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 p o r t i o n s o f the zones, the sul p h i d e s have t o t a l l y replaced tne sheared 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 occur, one s t r i k i n g n o r t h - e a s t e r l y and the other n o r t h - w e s t e r l y . The shear-zones occur i n what appears to be an i n t e r - f orraational sheet of 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 country-rock of dense t e x t u r e . The formation has been subjected to comparatively g e n t l e f o l d i n g along north-south s t r i k i n g axes. The ore bodies of t h i s type are probably medium to low temperature d e p o s i t s , formed at an appreciable depth below the o l d surface 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 of 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 to the concluding period o f the B a t h o l i t h i n t r u s i o n . Orerijodies of Type £. (Sfeibnite ngoid.) The ore-bodies of t h i s type are 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 of a t l b n i f c e , with accompanying py r 1te and very minor quantities o f galena, l a a f l a e - g r a i n e u quartzose gangue. This afcihaise occura 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 structure i n the v e i n matter, and «lso as a fine dissemination of minute needle c r y s t a l s i n the gangue-matter. The pyrite 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 ore-bodies of t h i s type appear to be confined 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 to favour the eraa aomeehat eloaor be the 'Bathoiitjj contact than the ores of type I . The depesite occur i n »ell-defined replacement sheer-acnes alcaig the course of f e l - s i t e dykes. These dykes have prob..;bly formed l i n e s of weakness i n the surrounding country-rock -.long which thy f r a c t u r i n g and shearing has been r e a d i l y c a r r i e d and sustained. The t y p i c a l d e p o s i t s are c h a r a c t e r i s e d by a high gold content and abnormally low s i l v e r values, 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 ore-bodies are probably of low temperature o r i g i n , formed comparatively near the 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 overing 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 genesis o f these depoaibs could not be established i n tne f i e l d , they are probably r e l a t e d to the f i n a l thermal a c t i v i t i e s of the b a t h o l l t h l e i n t r u s i o n ana l a t e r i n 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 type, Sit I k ine m a nfl^ Iekut R i v e r Area. T h i s l a r g e and l i t t l e s t u d i e d area extends from Taku to about TInuk I-Uver, a d istenoe of some 150 - 200 m i l e s . On the west i t i s bordered by the Coast Range B a t h o l i t h , to the east i t is u n d e r l a i n by unclose i f led P a l a e o z o i c and, probably some Fesozoic r o c k s . I t seems th a t e l l along the c o n t a c t , end f a r  t h e r from i t , forming- a b e l t about £5 r i l e s wide, m e t a l l i c min e r a l s have been f ounff. T h i s i s to be expected. However, because of the r e l a t i v e i n a c c e s s i b i l i t y of the r e g i o n , compara t i v e l y l i t t l e p r o s p e c t i n g and development was done. The work t h a t has been clone shows that the d i s t r i c t is .mineralised, and that 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 says; ! ,There are f o u r d i f f e r e n t kinds o f d e p o s i t s found i n the area: (1) magnet!te-pyrrhodits (Z) zinc (3) l e a d ( 4 ) copper. In some places the v a r i o u s kinds are completely i s o l a  t e d , whereas- i n others two o r more kinds may be present I n t e r  m ingling or grading i n t o one another." P. A. K e r r . Sum. Rept. 1926. p. 14 0. S. C. " " * « 1929, p. 11 G. S. C. '* " « 1929, p. 30 G. 0. C. 68. d e p o s i t s of the m a g n e t i t c - p y r r h o t i t e type appear to l i e d i r e c t l y on the igneous rock or In i t , rather than i n the sediments. A l t e r e d sediments are generally found associated w i t h there, though in some places the min e r a l i s e d messes seem to occur as lenses in the granite i t s e l f . " This i s then a contact netsmorphic type of deposit. '•'Galena and sphalerite usually occur intermingled or closely associated ». The mineralisation i s generally i n the sediments t t or near the contact....... Some deposits are cl c e r l y replacements of the sedi&ents by £ a ague and sulphides. iT A l l these deposits are very small, and probably have no co«MPereiel importance. The copper type of deposit, represents a l e n s - l i k e body of chaleopyrite i n bedded limestone. It i s also small and does not exceed a fev* feet in any d i r e c t i o n . Prom what has /been said i t seems, that a l l these depo s i t s are too f r a i l . , b.ixl too patchy to be of any grest i n t e r e s t . however -choir posit ion along the en stern contact of the Ba t h o l i t h , indicates, that t h i s portion of the contact i s min era l i s e d , end thr-1 therefore there* i s no re©son why larger de posits r-hould not cn:j.3t. I t OCO:J:3 cioar though, thnt the presence of minsralis- 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 large ore deposits. I t i a necessary i n conjunction with i t to have s t r u c t u r a l conditions which would tend to concentrate the available ; • literals at a point. Salr<on__ P iyjtj? h^rSH* The Sainton R i v e r Area w i t h the neighboring "Sear R i v e r and Stewart 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' of a t t e n t i o n . Thin 'n p r o h * c l y due to the f e e t that the 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 promising 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 as Premier, 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 of the C o o l . Curv. o f Canada thus summarises the economic geology of the a r e a ; "In the mines of Salmon R i v e r a r e a , the value s up to the present have been mainly i n s i l v e r a ad g o l d , although many of the de p o s i t s c e n t 9 i n econo&ie q u a n t i t i e s of galeae, sine b l e n d s , c h s l c o p y r i t e , and - y r l t e i n a *u&rtfc gangae, v;hich con s t i t u t e what Is known as a complex s i l i c e o u s ore. The m i n e r a l i s a t i o n of the d i s t r i c t i s a s s o c i a t e d w i t h the 0 l o s i n g stages of the Coast Range igneous a c t i v i t y — t h a t period •which has been so important i n commercial ore .deposition i n idr i t i s h C olumbia •,? The ore d e p o s i t s are connected w i t h the ''Premier s i l l s . " These are ta b u l a r masses o f sitiartz porphyry intruded between the bedding planes of the t u f f 3 of the Bear R i v e r formation. Their, maximum thickness Is i n the neighborhood of 1,300 f e e t . The rock i s grey massive, and i n hand specimens shows i n some oases phenoerystt) of ort h o c l a s e and s m a l l , i r r e g u l a r masses of quartz 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 intruded p r i o r to the mountain-building, 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 . Since the time of i n t r u s i o n , they have been subjected to f o l d i n g along w i t h the 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 deviate from the h o r i z o n t a l . "The ore deposits are of three main, types: (1) Base metal type (£) S i l v e r - g o l d type (3) Gold type. Base 'metai Type. The u s u a l moue of occurrence of t h i s type i s that of replacement and uisaemination i n c e r t a i n beds of t u f f s and t u f - faceous conglomerates, although veins occur c o n t a i n i n g the base metals. The ueposita are roughly t a b u l a r , s i n c e they correspond i n s t r i k e and dip w i t h the beus w i t h which they are a s s o c i a t e d . In B i g M i s s o u r i r i d g e , there beds s t r i k e along the ridge and d i p a l a low angle to 'the west and s i n c e the slope of the h i l l s i d e down to the Salmon rtiver g l a c i e r i s steeper than the di p o f tne tuffaceous beds, the m i n e r a l i z e d zones form l o n g , l i n e a r outcrops on b i g M i s s o u r i r i d g e . These weathered out crops, coloured brown by the presence of i i . o n i t e , are a marked fe a t u r e o i the r i d g e . The minerals present i n obese bancs are p y r i t e , chaleo p y r i t e , s p h a l e r i t e , and galena i n a gangue of q u a r t z . P e a r l y a l l the examnles of t h i s type occur on B i g M i s s o u r i r i d g e . The groups of claims from south to north are as f o l l o w s : i n a i a n . B i g M i s s o u r i , Hercules, and Kor t y - n i e , a l l of which contain mineral 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 given above. 71. The a l t e r a t i o n or meiamorphlsm of the rooks 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 not impossible i n many eases, so th a t the contact between the quartz porphyry ana the tuffs was not d e f i n i t e l y recognizee, and i t i s certain that over the gr e a t e r part of Big Missouri ridge t h i s contact i s buried underneath the t u f f s and the tuffaceous congloracrates. S i l v e r Gold Type. The ores of t h i s type.occur in veins and v e i n - l i k e replacements i n quartz-pornhyry ana at the contact of the por phyry ana the 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 are p y r i t e , c h a l c o p y r i t e , sphalerite, 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- nides and aulpho-areenides, native s i l v e r , and gold. The gan- gue i s rat h e r abundant and i s almost e n t i r e l y quartz. The ore- bodies of the Premier mine belong to this type. rfhe native s i l v e r is 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 not seen i n the unfractured v e i n material. In a d d i t i o n the fractures show a strong down ward movement of water and contain considerable amounts of limonite. The s i l v e r occurs as thi n leaves or plates f i l l i n g s m a l l cracks i n the ore. Some occurs in hair l i k e forma (wire s i l v e r ) and nuggets in small quartz urnsses. The l o c a l i z a t i o n of the s i l v e r to the imraeuiate v i c i n i t y of the fractures points to a secondary o r i g i n for the native s i l v e r , or, i n other words, the n a t i v e s l i v e r is due to secondary enrichment. 72. Gold Type. A single ore-tody In 1;o. 2 tunnel of the Premier Pine I s o f t h i s type. It i s a s i l i c e o u s , heavy sulphide deposit. Quarts and ->jrite arc the predominating minerals,. Sai a l l quan t i t i e s of chaleooyrite, sphalerite, and galena are present. Assays ©how high values in gold, 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 ore bearing solutions emanating from the g r a n i t e during tne f i n a l stages o f cooling entered the f i s s u r e s and shear zones and at favourable l o c a l i  t i e s formed ore-bodies of coiu&ercial s i z e . The ore-bearing s o l u t i o n s which foraou the ore bodies 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 spread l a t e r a l l y along favour able horizons in tne t u f f s and t u f f conglomerates. In other cases, as at the Prettier Mine, the ore-bearing solutions found the sheareu contact between the quartz porphyry s i l l s and the t u f f s a favourable place f o r ore d e p o s i t i o n . The eviaenee available points out, that t h i s occurred probably in Upper Jurassic tioie. 73. A l i c e A r m D i s t r i c t . The area i s on the eastern border of the Coast Range B a t h o l i t h and the mineral d e p o s i t s are part of the great miner a l i z e d b e l t which extends w i t h few i n t e r r u p t i o n s along tno eastern c o n t a c t . An h i a t u s occurs i n the b e l t at Bass R i v e r where no mineral d e p o s i t s are known. A l i c e Arm i s at the southern ena of that part of the b e l t that extends northward and that includes the m i n s r a l de p o s i t s o f Portland Canal, 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 of 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 or f i v o h e aulags: (1) Molybdenite d e p o s i t s . (2) High grade a l i v e r - b e a r i n g veins i n a r g i l l i t e . (3) S i l v e r load 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) Ohaleopyrita d e p o s i t s . •£he high 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 are quartz'veins 6 f e e t or less i n width, which are mi n e r a l i z e d w i th p r i nary e i l v e r mi n e ra 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 rocks are v e i n l i k e , u s u a l l y much wider than b f e e t , con s i s t of qua r t z , b a r i t e , ana country rock, and are m i n e r a l i z e d with s i l v e r - b e a r i n g galena and t e t r a h e u r i t e . Owing to secon dary enrichment some of the deposits of t h i s type contain r i c h s i l v e r o re. (George Hanson. " M i n e r a l Deposits of ^ l i c e Arm D i s t r i c t . " Oeoi. Sur. Canada, Sum. Kept. 19£8, p. Zl.) 74. She s p h a l e r i t e deposits are v e i n - l i k e and c o n s i s t of quartz, caleite,-country rock, and r e s i n colourea s p h a l e r i t e , uepos i t s vary considerably In size and are u s u a l l y i n 8eyrisentaiy rocks. The chalcopyrite deposits are v e i n - l i k e and consist of quarta, country rock, and chalcopyrite. The d e p o s i t s are mostly i n volcanic rocks. In raany respects they c l o s e l y resemble the sphalerite deposits and say be c l o s e l y r e l a t e s to them i n o r i g i n . • ' Hanson concludes, that the deposits have not been studied s u f f i c i e n t l y yet, to be able to formulate any s a t i s  factory theory to account f o r the various d i s t i n c t types of mineral deposits. The deposits are very numerous, and considerable work has been spent on development, but so f a r the Dolly 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 of metal (1,300,000 oz. of s i l v e r ) . , But soae as Hanson says, have outstanding . p o t e n t i a l i  t i e s . 75. The Skeena and neighboring D i s t r i c t s * A l a r g e body of n j r l te w i t h associated chaleopyrite, occurs some distance u p 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 of the main body of the Coast Range Ba t h o l i t h , mineral bearing veins are numerous. TTo large ore bodies are known, but the veins though narrow are commonly very r i c h . They are euartz- sulphide veins containing free gold, and the value i n aost instances is almost en 11 re l y in gold. A short distance east of 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 com plex nature. East-and west of Skeena- E i v e r , in the neighbour hood of Fiddler and Lome Creeks, gold quartz veins are again the r u l e . In the v i c i n i t y o f Haze'lton are numerous small to modernte-sizea veins containing a great variety of a i n e r a l s , among which may be mentioned gold, jamesonite, waiframi t e , s c h e e l i te, molybdenite, s a f f l o r i t e and the common .minerals of copper, lead, zinc, s i l v e r , i r o n , and arsenic. On Hudson Bay mountain the veins are mostly small, and are mainly of the s i l v e r - l e a d type. Veins containing arsenic and gold are also present. Hanson also mentions a vein near Francois Lake which contains bitumen and phosphate minerals, but as l i t t l e i s (0. Hanson. "Prince Rupert to Bums Lake, ?.. C." 0. S. C. Sunra. R e p t l 19-24, p. 38.)' 76. known about i t , nothing more has to be a a i d . Fear Fasnelton occurs an int e r e s t i n g deposit of Tungsten, described by E. Ku r s t , In 0. 3. C. Suam. Rent, f o r 1924. This deposit, together w i t h these of arsenic, copper-, lead, e t c . , occur in Rooher Detoule mountains, southeast of E a z e l t o n , The deposit occurs along a shear zone, in the grano- d i o r l t e . Presence of such minerals as wolframite and s c h e e l i t e indicates high temperature and pressure conditions. The interest of t h i s deposit l i e s mostly in the f a c t , that d e p o s i t s of other than conventional type may be expected, f a r t h e r from the main Coast Range Ba 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 attention than has been heretofore given them. •i Another mineral deposit, described by Lang i s also connecter with a small 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 constituting the Owen Lake mine, are ve i n s f i l l i n g shear zones and f r a c t u r e s in the m i c r o - d i o r i t e and i n included blocks of anderite. A single vein, 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 r fauina, t h i s mineralization i s believed to be associated with the g r a n i t i c i n t r u s i o n . The veins are roughly p a r a l l e l , f i l l i n g shear-zones and fissu r e s i n m i c r o - d i o r i t i . They vary from mere stringers to A. H. Lang. "Uwen lake Mining Camp." C!. S. C. Suam. Rent. 1929. p. A. n. 62. 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 of 5 to 6 f e e t wide. 2here are two g e n e r a l types of ffilitei'alization: e h a l c o p y r i t e - s p h a i e r i t e and 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 between the two types occur, and as yet 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 s i l v e r content, and a moderate gold content. The gangue minerals a r e : rhodoohrosite, quartz, chalcedony, and b a r i t e . •:. -The sphalerite-galena type c o n t a i n moderate s i l v e r values ana a low gold content. b'he veins are of the epithermal 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 accom pany i n g enIthermal deposits. (2) Chalcedony Is a c h a r a c t e r i s t i c gangue mineral 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 minerals are of epithermal type. The age of the c \ i c r o - d i o r i t o stock, with which the deposits are associate-, is considered by T&jtir to be post- Lowe r Jn r a s s I e. 78. quoting M a r s h a l l : — "As yet very l i t t l e p rospecting has l e a n done i n t h i s r e g i o n , and only along p a r t s o f the trunk streams. The d i s  c o v eries so f a r sa&e prove t h a t mineral deposits occur and that there e x i s t s at 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 zone of considerable extent. Cold, s i l v e r , l e a d , z i n c , and copper have been found i n veins on Chikamin r i d g e , south of i'Jhitesall Lake, and on Sweeney mountain north 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 Chikamin ana Sweeney mountains are the important 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 deposits on Chikamin ri 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 outcrop near a number, of sm a l l i n t r u s i v e masses. i'hoae of Sweeney mountain occur both i n uiae sedimentary and v o l c a n i c members. Ine most i n t e r e s t i n g showing, that In the Emerald group of claims deserves more P e t a l l e u d e s c r i p t i o n . Sweeney mountain i s formed of rocks of the HazeIton group, 11 t h o l o g i c a l l y s i m i l a r to rocks of the same group on Chikamin Ridge• West of the westernmost peak of the mountain, the Coast Range i n t r u s i v e s invade the members ••>£ tne Hazel ton group. The mineral deposit occurs 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 . Quartz f i l l s f r a c t u r e s i n the t u l f a , f o r n i n g veins up to 18 inches wide, -he quartz i s f r a c t u r e d i n a l l d i r e c t i o n s , . J. R. i & r s h a l l , 7/hi te s a i l-?ahts& Lakes Area, G. 3. C. Sumn. Rept. 1924, p. £2 A. 79. and these f r a c t u r e s are f i l l e d with c u b i c a l and ste e l galena, and- subordinate amounts of p y r i t e , chaleopyrite and s p h a l e r i t e . She t o t a l length of the deposit from adit p o r t a l to the orest of the ridge i s at least 2,000 f e e t , and the d i f f e r  ence i n elevation about 900 f e e t . From. But suk lake to Chi loo lake. The extensive, several hur.dred miles long, tract of land from Eutsuk Lake to Chllco Lake has been very poorly prospected, and no great discoveries have been made. There are only three properties that deserve some atte n t i o n . These are: {1} A deposit of auriferous arsenopyrite, situated about 2 miles north of Perkins Peak. (2) A deposit of Hematite 1 mile south of Perkins Peak, and {3) The Morris mine or the Tatlayoko Lake Gold Pines Ltd. The gold-arsenic deposit i s situated a t an elevation of 7,800 feet near the brow of the steers, northward-facing side of 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. Tatla-Bella Coola Area, B. C. 0. S. C. Suam. Rept. 1925, p. 155 A.} (V.DoImage. Chllco 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 Eye Lake to P e r k i n s Peak. The ore bearing v e i n s occur i n a s e r i e s of sedimentary rocks composed of blaek a r g i l l i t e s , dark brown a r g i l l a c e o u s sandstones, and f i n e , cherty conglomerates over l a i n conformably by t h i c k beds of coarse v o l c a n i c breeeia which form the summit of P e r k i n s Peak. The s t r a t a s t r i k e north 60 to 70 degrees east and d i p southeast 40 to 45 degrees. F o s s i l s found i n the near v i c i n i t y of the veins, are reported to be of Lower Cretaceous age. The rocks are cut by the Coast Range B a t h o l i t h , the contact of which makes a U shaped bend around the southwest aide of Perkins Peak and i s £ miles southeast, 4§> mi l e a southwest, and l-.V miles northwest of the deposits. A small d i o r i t e stock, less than o n e - f i f t h of a mile i n diame t e r , 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 deposit. The mineral is in large quartz veins or s i l i c i f i e d zones which s t r i k e north ana are nearly v e r t i c a l and, therefore, extend up the steep valley w a l l . Arsenopyrite Is disseminated i n quartz. The showings are quite large, but the amount of containeu gold unfortunately i s small. A deposit of exceptionally pure Hematite occurs in a large cirque on the soutneast side of Perkins mountain. I t i s s i t u a t e a near tne bottom of the cirque on the north side at an elevation of 7,500 fe e t . It i s reached by a good t r a i l from One TTye Lake or E l i n a Lkin f i a t s , both on B e l l a Gooia t r a i l . 61* The Hematite occurs i n a bed of t u f f , which, with other types of volcanic rock, i s interbedded with Lower Cretaceous sedi ments, fhe t u f f bed i s 10 to 20 feet thick and i s , i n places, completely replaced by Hematite. Small veins of quartz and spsoalarite out i t and adjoining beds. The beds s t r i k e south 70 degrees east and dip 20 degrees south. The sedimentary and volcanic beds l y i n g between the Hematite deposit and the con ta c t of the B a t h o l i t h , which is about 1 mile to the south, are thoroughly impregnated with p y r i t e , and along certain well developed shear-zone3 near the iron-bearing t u f f the rocks are completely altered to tale and s e r i e i t e schist containing a large 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 Lake Gold i ' i n e , b e t t e r bnowa ae th?- V o r r i s a i n e . 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 thenst o f the south end of 1'atlayoko L a k e . Zt is a t an elevabi.cn of 15,900 f e e t , Just above t i m b e r l i n e , and 3,200 feet above the 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 the s i d e s o f a steep r o c k y g u l c h . The v e i n a cut Trlassie sediments, c h i e f l y a r g i l l i i e s ant f i n e Baj.idatof.cn, but with one thin "bed of l i n e c h e r fey a on y l c r e r a t e . a snort distance northeast of 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 probably r e l a t e d to the boast 'van-re dal.->.oli t h , the edge of which is s i t u a t e d a fet? miles to the sou t h • I'any dykes o u i the sedi ments and range i n composition from d i o r i t e to b a s a l t , the m a j o r i t y being b a s a l t i c , biaay, i f not a l l , o r e younger than 8 2 . the veins. The veins consist of quartz, through which i s disseminated f a i r l y evenly arsenopyrite, 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 are closely associated with the s t i b n i t e which tends to occur i n the central parts o f the - veins, whereas the gold, arsenopyrite and pyrite are more p l e n t i f u l along the margins. The rock adjoining; the veins has been altered to a very dense greyish green material resembling chert. 83. Taaeko V a l l e y . Limonlte i s found, i n th© Taseko V a l l e y . The dep o s i t s are s i t u a t e d i n the upper p o r t i o n of the v a l l e y and i n the 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 , the t o t a l area i n which the beds of l i m o n l t e a r e found being about 50 square m i l e s . The rocks 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 are an assemblage of b a s a l t i c flows and p y r o c l a s t i c s with some quartz 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 the "'Taseko formation. ' This v o l c a n i c formation of Tertiary age, overlies unconformably the 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 bog-iron ore, are s i t u a t e d i n seven d i f f e r e n t l o c a l i t i e s . They c o n s i s t of sheets of brown limonlte of 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 of t h i n l a y e r s of brown, c e l l u l a r , and generally loose-textured l i m o n l t e l y i n g p a r a l l e l to the surface of the ground on which they r e s t . The Hco 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 half an inch, and each of i t breaking to the fineness of sand. The i r o n i s derived £ro/r f i n e l y divided pgrito 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 of the Taseko format ion.' The iron sulphate solutions formed by the oxidation and leaching of t h i s p y r i t e t r i c k l e down the mountsin slopes and depos i t a t the f i r s t favourable iocaU.jn, b a i l d i n g uo s u e d o £ llmonite. J . D. IfacEenzie.' "The limonite deposits i n Taseko V a l l e y . n G. 3 V C. Su m. Rept. 1920, p. 42 A. 84. Gun -Crsek Area. There ?re no producing (fines i n the Sun Creek area at present, hut severs 1 Lit eresting copper and gold deposits occur The r.ost irrt orient drpoeS t& of C~vn Creek erea, ere four low- grade coprer-golo dogosits, situated in the Coast Range Pstho- l i t h along Its contact- with the Cretaceous voleanios. The mineralized part of the Batholith i s a normal grano d i o r i t e composed of fresh andesine, hornblende, b i o t i t e , orthoclase, and magnetite. The segregation of the ore minerals in t h i s p e r t i c u l a r part of the Batholith seems to be dependent on the development of peculiar orbicular structure. The groncaiorite 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 surfaces, 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 toxture. The i n t e r i o r s of the nodules consist of normal massive g-rano&Iorite s i m i l a r to the adjoining non- orbioular parts of the B a t h o l i t h . The i n l ©modular portions are made up of m i a r o l i t i c gracodiorite together with- quarts and chaleopyrite. The m i a r o l i t i c c a v i t i e s are lined with w e l l - formed c r y s t a l s of quartz, orthoclese, lsamontite, and chaleo p y r i t e . In places there i s considerable chaleopyrite dissem inated i n the quartz, and oecassionally blebs ol" t h i s copper mineral up to 3 inches i n diameter. Chaleopyrite i s also sparsely disseminated i n the marginal portions of the nodules. Small amounts of p y r i t e are associated with the chaleopyrite. (V. Bolcage. 'Gun Creek Area, B. C." C. S. C. Summ. Kept. 1928. p. 78 A.) 85. l o g o l d o r s i l v e r m i nerals have been observed i n the s u l p h i d e s , though assays show these metals to be present i n small amounts. T h e deposit i s exceedingly low grade averaging l/> i n copper. - The Bridga R i v e r Area. "The most Important ore d e p o s i t s of the Bridge R i v e r are®, and i n f a c t the e n t i r e L i l l o o e t mining d i v i s i o n of B r i t  i s h Columbia, are the g o l d - q u a r t s d e p o s i t s . f t But t h i s i s .not the only type of d e p o s i t s and the d e p o s i t s may be c l a s s i f i e d as f o l l o w s : — (1) Gold quartz d e p o s i t s , id) P l a c e r gold d e p o s i t s . , ( 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 . In t h i s paper we are only concerned w i t h the. m e t a l l i  ferous d e p o s i t s of the lode type, end so w i l l d i s r e g a r d the p l a c e r d e p o s i t s ana the non-metaHies. The g-old-qurrtz deposit? o f the Caflwailnder Creok b e l t , occur 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 Borne, Coronation n.nd Pioneer mines ore located on t h i s body. (P. S. PeCann,' ; ,Geology end ?'ineral Deposits of the Bridge R i v e r Map-area, B . -C." G. S # C. iiemoir 130, 1922.) 86. Many of th© important f i s s u r e s of the d i s t r i c t show sheeted structure i n Vuu'u thw waiii* o i the veins contain p a r a l  l e l j o i n t i n g planes which are themselves p a r a l l e l to the. main x'is&ures. The compressive f o r c e s acting i'roia the west, which were responsible f o r the f o l d i n g and crumpling of the Cadwailader s e r i e s on the western limb of 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 that noted i n the a u g i t e - d i o r i t e . 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;/ are c h a r a c t e r i s e d by frequent pinches and swells along t h e i r e n t i r e length. Those of great est economic importance dis p l a y a banding or ribbon s t r u c t u r e due t o subsequent :.\o\ ament along the plane of the veins, and the sheeting of the quartz veins along what may have been li n e s of origin© 1 sulphide deposition. The hydrothermal solutions have had a profound effect upon the v/sll-rock close to the f i s  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 rock c o n t a i n i n g pyrite and ai«enopyrite i n . c r y s t a l s . The gacgae minerals are: .quarts, c a l c i t e , s e r i c i t e , s i d e r i t e and dolomite. The metallic minerals ere: £Old, which occurs as p a r t i c l e s scattered through the quartz of the veins, anrt so/retimes i n r i c h l y concentrated ore shoots or pockets, where I t i s easily seen vrith naked eye. Sometimes i t occurs as th i n plates or coating an aiikenalded p a r t i n g s i i i sheeted or ribboned v e i n s . I t alfco occurs f i n e l y d i s t r i b u t e d throughout the sulphides i n minute f i l m s and p a r t i c l e s . Free m i l l i n g gold 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 , c h a l o o p y r i t e , 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 mi n e r a l s are found to he usually I n d i c a t i v e of the presence of high values of gold i n the veins. The presence of t e l l u r i u m i n d i c a t e s t h a t the deposits may he classed &s goId-tellurium type of deposits, and i t would be i n t e r e s t i n g to compare them with the s i m i l a r deposits' farther n o r t h , l i t r e , f o r instance, the Engineer F i n e , i n A t l i n d i s t r i c t . The veins are o x i d i z e d to a depth o f about 100 f e e t . There haa been movemont along the planes of the veins since thoy 'were formed, bub the dimensions o f t h i s movement v;ere small. Til e solutions from 'which the vein mater in Is were p r e c i  pitated a re believed to be g e n e t i c a l l y related 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 constituting 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 thin 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 of t i.^ .s avvat. hnve intervened betw een the Intracioa of the a u - I t e - d i o r i r e and the Tarnation of the veins, to have permitted of the s o l i d i f i c a t i o n of the i n  trusive ta such an extent tha t i t mould y i e l d to deforcing atrei iBea by Irac taring. The augice-dlorite has been intruded by l i g h t - c o l o u r e d a l b i t i t e porphyry dykes which are considered to- be a l a t e r d i f f e r e n t i a t e of the augit e - d i o r i t e magma, and the veins them s e l v e s , \3hich eut across these d y k e s , are believed 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. and, t h e r e f o r e , of the saj-t- general age as the 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 only 2g- mi l e s away, and the qunrtsi-diori•:';<•: doon not co n t a i n g o i d - q u s r l z v e i i m . The a u g i t e - u i o r i Ls not known to .have i n t r u d e d f o r m a t i o n s younger than the Ga&wa U n d e r s e r i e s , which l a Upper T r i a s s i c age, whereas the S e n i o r g u n r t z - d i o r l t o I n t r u d e s sediments of known lower Cretaceous ago• The o.ug:l.te-«:liorite, t h e r e f o r e , on account of i t s l i t h o l o g i c a l c h a r a c t e r s , i t s g r e a t e r motomorghism, MB& i t s r e l a t i o n up i n t r u d e d f o r a a t i o n o , i s c o n s i d e r e d t o be o l d e r than 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 placed as l a t e J u r a s s i c . S l l y e r - C o p p e r P e ^ s i t In view of d i f f i c u l t i e s of t r a i l apor t a t i o n , c l i m a t i c condlt ionn, and the low tenor o f the ore i n e i g h t , the copper- s i l v e r d e p o s i t s have not been a c t i v e l y developed. "he most p e r s i s t e n t v e i n of t h i s tgoe i s found on t h e side o f : " e O i i l i v r a y mountain, whence i t way be traced f o r over a m i l e northwestward. I t d i s p l a y s - banded s t r u c t u r e due to f i l l i n g of the f i s s u r e by c r u s t i f les t i o n . The m e t a l l i c minerals have been deposited i n t h i n , bonded *ggre.-*3ton p e r s l l e l to the 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 the v e i n permeable to surface r a t e r s , w h i c h h.-ve p e n e t r a t e d i t , t h e r e b y causing 89. the oxidation of the tetrahearl te. The r e s u l t i n g carbonates of copper, azuri 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 t e t r a h e d r i t e f azuri Le, malachite and galena in asiall amounts. i.*iJoc the miner a l l a y t ion of the vein and i ts f i e l d re l a t i o n s , i t i s probable that i t via a formed at intermediate depths and iz genetically related 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 vein materials 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 small ©mount. Antimony Ttepoa:!ts. - The antimony deposits are closely related to the i n t r u  sion of diorite-porphyry 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 fo r the nost part In i r r e g u l a r .1 ens-sheped masses through the quartz. They appear to be confined to a narrow belt on the western limb of the Pridge River a n t i c l i n e , and have been found only within the Fridge Rir- er s e r i e s . 90. Chromite JDeposits. A s s n l l deposit of ohromi<m ope occurs on the northern slope of T a y l o r b a s i n i n the northwestern corner of the raap- a r e a . I t Is associated with a s m a l l outcrop of serpentine 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 whits, compact hydrated s i l i c a t e of fiagneoias. Moroseopic diamonds were found In the c h r o a i t e . The close association of the chroMte with the serpen tine rocks points to a genetic r e l a t i o n s h i p . I t undoubtedly represents a be s i c c once-it, rat ion by ^agnatic d i f f e r e n t i a t i o n within an o r i g i n a l l y oli'Td ne-hold i n - mrna , the oiiroir.ite probably b oj.ng the f i r s t metc< 13J e nino r a l to erystelliKe,, 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 dissolved carbon in the molten &e>;mn» 91. Coqjuihalia Area, B. G. S t r i c t l y speaking, the C o q u i h a l l a area should not be in 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 la y s outside the Coast Range and belongs t o the Cascade Range. But as i t shows the same properties as the other ueposits of B r i t i s h Columbia, i t was decided to give a brief description of the economic geology o f t h i s area, x ?ol Lowing 0. Hi. C a i r n e s ; — "The economic minerals axm metals i n their present decreaoing order of imports „neo inclade; gold, s i l v e r , copper, molybdenite, arsenic, platinum, l e a d , manganese, and ir o n . They occur i n both d e t r l t n l and lode deposits, i n the former g o l d nnl platinum nr.3 tho only M i n e r a l s of importance. "die lode deposits of c c K m e r c i r l value Include; g o l d , s i l v e r , copper nud r olybdennm. f-oIci ores HP<? the r-ost. im..« orient 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 sections of the crea j-nd. in quite different geological e s e o c i e t i o n s . T h e i r mo:vt important &evel< g^ent i s confined to gold-quartz veins i n the ;,ner si?,to belt end the underlying andesite greenstone member nf the Crone Creek se 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 attributed to & large d i o r i t e intrusive which closely f o l l o w s t h i s contact. Other gold quart *a veins seem, ho .•••ever, to bo genetically r e l a t e d to s n n l l e r and nore acid p o r r n y r i t i c dykes and g i l l s , i n t r u d i n g (G. K. Cairnes. " C o q u i h a l l a .Area, B r i t i o h Columbia." G. S. C. Memoir 139. 1924.) 98. the slates. The quartz TTCH- ,; occur as combinations f i l l e d and replacement vein.type. Thoy are eo^only bedded with the s l a t e s or occupy i r r e g u l a r fi.is,;rs ; . i i n either slates or greenstones, fhap a l s o occur i n shatter '/-ones i n e i t h e r o f • the se roohs and appear as a network of linked v e i n l e t s forming a zone many yards wide and p e r s i s t e n t over many hundred and ...•ossioly thou sand f e e t , i n a l l these types, g a l a values are very 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 to a less extent p y r i t e or c h a l e o p y r i t e ^ Rp© most abundant. 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 smaller proportion of a i b i t e . Sulphide ninorols nre dir?so::.insted c i t h e r i n S e g r e  gates of fine grains ox- pn Irrger i r d i v i d u o l c r y s t a l s , but never in s o l i d wssea. They f no luce.- pyrrr.otite, ...yriio, arsen- opgrite, /.:rd cbrleopyr.lfs, nr-.r.ed. i ' i order of elr-nndaiu-e, and deposition. Pyrrhotito- i s , hov;ever, not txz eo&>;,orj i n the quarts ve 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 galena, blendo, aiid s t i b n i t e are encountered. Gold i s c h i e f l y associated with the ars e n o p y r i te and occurs e i t h e r i n the f r e e state or so f i n e l y wixed or intergrown w i t h t h i s or other sulphides as to be even micros c o p i c a l l y i n v i s i b l e . Gold ores also occur a t the /sufeas mine where the ore minerals are massive a u r i f e r o u s a r s e n o p y r i t e . Chaleopyrite and pyrite are associated in varying amounts i n a quartz gangue. The m i n e r a l s occur i n well-defined veins occupying shear zones i n a moderately coarse-grained, b a s i c p l u t o n i e rook t h a t v a r i e s 93. from 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 regarded as of Upper J u r a s s i c ago. i h c v e l a a a r e ad i n t e r m e d i a t e character as ragards d a t a temperature and depth o f formation. Arsenopyrite i s a u i ' f i o i e n t i y auunuaak ana massive i n ch a r a c t e r to j u s t i f y i t s separate treatment f o r araenic. She o r i g i n ox these ore de p o s i t s i s r e f e r r e u 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 the older p l u t o n i o r o c k s . X S i l v e r o r e s are o f p r e s e n t comme re i a l importance only a t the Eur e k a V i o t o v i f c .mines on b i i l v s r peak, bney occur 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 te and low te 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 i.n n :--t-«.s«ive C r e t a c e o u s c o n g l o  m erate. ?he gnn-ne i a c l u d e a .? i d a r i t e , Itmo/site, and qv.arts i n t h i n order- of dec r o w n i n g a l u n d r n c e . The p r i n c i p a l ore minr-rnX "J:- an R: g g o n i f f . r o u a tctnah'.;drl -a- c-;.rrging i . v a r y i n g p r o p o r t i o n of l e a d . Secondary c o n c e n t r a t i o n of.the vein material hy surface w a t e r s 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 o f the s i l  v e r and 3end nt t'-e esrpenee of the o t h e r metallic and gangae m i n e r a l s . V a l u e s up to gVOO n tac have been obtained from theso e n r i c h e d s h o o t s or ore pockets. Average v a l u e s i n the primary v e i n deposits v e r y up t o ebout ,GO, but a r c ne a rule * C a i r n e s , C. n. i'.sm, 139. 1924. 94. The only copper ores o f economic value occur a t the Independence mine, liiey form veins 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 large granite porphyry dyke cut ting the Eagle g r a n o d i o r i t e and rocks of the Tulameen group. This property was examined by Camsell who regarded the ore deposits as strongly resembling the Butte type. The gangue includes altered granite porphyry and secondary quartz, 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 chaleopyrite, but p y r r h o t i t e and p y r i t e are abundant and some chalcocite, c u p r i t e , blende, and molybdenite were observed. Tetrohedrite i s also reported t o oocur here. One important molybdenite deposit has been discovered on the Dominion t ' i r e r a l Group i n the Cretaeeous granite on the summit west o f l e g o . The sn.lphiOe occurs i n a high temperature quarts ler-s of i>e--vatitle o r i c i n and i s also iiaoi'e.gnated through the adjoin in-: grorJLto. The .aiolgbdonite o c c u r s in l a r g e flakes and lumps i n the ,i;arU a/id i n d j sse&int'ted t r a i l e r flakes i n the c o u n t r y rook, homo i ocoadi' rp oo-.idati >n to ye H o w i.,olybdite has occurred, f o other ore mine r a l s v;ere oh nerved»*' 95 i r t i i i i Dis c r i c t . 96. Atlin . D i s t r i c t . . Physiography. x'ha A v l i u dt«3vri.ot *rs* ..jv>ii tvo uis»!>inctAy u l i f e r e n t piaysJ.ograpb.ic p r o v i n c e s . Une i a that of the Coast xtange, and tne o t h e r the xitkoji p l a t e a u , i h e Coast ^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 i a a i n l y - Ox k n i f e l i k e r i d g e s , needle submits, and a b r u p t l y i n c i s e d v a l l e y s , and everywhere considerable i c e and snow are to be seen throughout t h e e n t i r e y e a r . The Yukon 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 the p l a t e a u s u r f a c e . f r o , j such a p o i n t the o b s e r v e r i s struck 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 u p l a n d siveeping avay i n a l l d i r e c t i o n s t o the horiz o n and b r o k e n only here and t h e r e by i s o l a t e d r e s i d u a l masses thv.l r i s e abov« the 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 & surface of c o n s t r u e t.1 on, but i t i s r e a d i l y seen t h a t i t truncates a l i k e r o c k s of v.-idely v a r y i n g degrees of r e s i s t a n c e . The up» l a n d s t a n d s a t an average e l e v a t i o n , o f £,000 f e e t . 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 the Coast fenge ii o u n t a i n system i s v e r y grac.ua 1, BO crucb i o ^ t h a t i t i s , i n p l a c e s , d i f f i c u l t t o determine where one ends and the other b e g i n s . The wide d i f f e r e n c e between t h e topography of the Coa s t Range and th a t of the Yukon p l a t e a u seems t o be due mainly to t h r e e c a u s e s . I n t h e f i r s t p l a c e , the Coast 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 , nor a l t e r n a t i n g hard and s o f t l a y e r s to be emphasized by e r o s i o n , so. that &u'fc-&wial agonoies have had no r e g u l a r c o n t r o l and have thus produced very e r r a t i c forms. The i r r e g u  l a r j o i n t i n g planes i n these r o c k s have a l s o i n places a s s i s t e d i n the production of bold I r r e g u l a r topographic forms. Secon d l y the g r a n i t i c rocks are harder and erode less r a p i d l y than the rocks of the p l a t e a u and, t h e r e f o r e , have caused the Coast Range i n t h i s d i s t r i c t to r e t a i n a g r e a t e r general e l e v a t i o n than the r e g i o n to 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 coast Range i s no** higher than the rlntenu region, 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 long ago vanished from the plateau region. Thus once a l i n e of dnmarcnnl ^a was established between the Be tv/o t e r r a n e s , t h e i r feature:! have stesd i l y become more and more contrasted. It in believed that the region has auffered several c y c l e s of u p l i f t nnd e r o s i o n . During Jurassic, the Coast Range B a t h o l i t h wr.s intruded and t;.o (oast Range atooa high. Cretac eous s ? r a period of e r o s i o n . -„uoilag "chofield;^ '"T hroaghout tnc Gratacoou;;, thoae four gree t mountain chains, Vancouver Inland, <" ueen Charlotte I aland Range, the Coast Range of B r i t i s h Columbia, the diorra Revada Range, the Columbia-Selkirk Range and the i * l a s k i d e s , as w e l l as Caeoadia, were areas ox e r o s i o n , supplying sediments on both flanks of # • S . J . S c h o f i e l d . The g e o l o g i c a l record of the C o r d i l l e r a i n Canada. Transactions of the -Royal Soc. of Can. V o l . XVII , 1923, Sec. IV. 98. these highland masses......* The g r a n i t e pebbles which occur i n Cretaceous i'oriaation 01 n* prove t h a t the g r a n i t i c sores o.i* t n e g r e a t J u r a s s i c mountain chains 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 con tinued, e l i i o s t without i nt e r r up t l on u n t i l the Lara/aide r e v o l u  t i o n i n e a r l y T e r t i a r y t u n e , . , . , " ' f i i e p r e s e n c e of Cretaceous r o c k s i n the v a l l e y s i n the C o a s t iiango, s uch a..- those o f ' f c r r i a u n Lake ana k i t s c x & a l l u f f i h i v e r , shows t h a t the c o a s t r.ange cay have been i n p a r t sub merged by the c l o s e of the C r e t a c e o u s , from t h i s i t &ay be con cluded t h a t the f o u i - g r e a t J u r a s s i c mountain chains were r e  duced to a c o n d i t i o n approximating peneplanation by the c l o s e of t h e C r e t a c e o u s p e r i o d . ' 1 "In e a r l y T e r t a i r y time, o s o g e n i c movements of p r i m a r y importance "the laramide r e v o l u t i o n * a f f e c t e d the # 1 0le r e g i o n of the C o r d i l l e r a and the f"rent P l a i n s . The peneplaned s u r f a c e of the g r e a t J u r a s s i c n o u n t a i n c was u p l i f t e d , t h u s s t a r t i n g a ne?; c y c l e o f e r o s i o n w h i l e the bj-.eins o f s e d i m e n t s t i o n were f o l d e d snd formed nev m o u n t a i n c h a i n s , than p r o d u c i n g f o u n t a i n s f o r the f i r ? r t t i u e i n i h o c c c e r t e of t r e I n t e r i o r P l a t e a u and the hookp M o u n t a i n rev i o n w h i c h o oca peu the f o l d i n g of the J u r a S B i d e r e v o l u t i o n . " ' Over c o n s i d e r s Ole p o r t i o n s of the d i s t r i c t , the p l a t e a u S u r f a c e has been a l m o s t i f not v o l t e d e s t r o y e d by l a t e r e r o s i o n , ana i n such p l a c e s the t o c o g r a p h y c o n s i s t s of i r r e g u l a r l y d i s  t r i b u t e d , rounded h i l l s , ma-y o f them g e n t l y contoured and w i t h summits t h a t a r e i n many cases r e m a r k a b l y uniform 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 occupied by Taku Arm of I'a^ish Lake, ana nflj.a Lu/.e. duiat-. rdHsu oroas v a l l e y s join, the main valleya. Very often the so eroaa v a l l e y s are also submerged, or have small e uparate lakes, or rnmnanta o l lakos, streams ana marshes. l'neae v a l l e y s «ere apparently old stream channels, which wore l a t e r accentuated 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 slopes, and widened and lowered, t h e i r f l o o r s , The v a l l e y s thus produced were wide, deep ana steep sided. The ice also, i n places f i l l e d the f l o o r of the v a l l e y s with g l a c i a l s i l t s , sands and g r a v e l s , boulder s l a y s , etc. f , T>, Cairnes considers that the formation of such lakes as Taku bra and. Tutohl Lake, v/hich, non occupy the por tions 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 ice retreated 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 debris, causing reversed slopes and e f f e c t u a l l y impounding the water above. ?oHawing 3. J . Cairnes,; 'The ' i f shaped, steep-walled character o f . a l l the main v a l l e y s , and the reversed slopes of many, causing l a k e s to form i n them, are due, mainly at l e a s t , to g l a c i a l a ction. 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 vigorously s i n k i n g " D. D» Cairnes, Ifem.' 37, G. S, C. 100. their channels i n the u p l i f t e l s u r f a c e . Throughout the area Seep V aksn neft * ncf onr 1*x»rp 1 £31 _ RIP.d e, sret t^ere 5n T'loi v i t D c c n c t i n e , \:tvc invnc c-S by g l o c i e r s fi'On the noun tains to the t-ovith, nouthunnt ana v;est, v.-hieh have profoundly e f f e c  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 topographic features and neuueos the r e l i e f , by eroding material fron thn higher olsvutionn and depositing It i n the depressions, hut where tko inn occupies o.nl.y the vs. 3 l e y s , as was the cane o\er the greater part of A t l i n d i s t r i c t much grea 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 deepened, th** naxiaiun e l i e c t being produced 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., faku arm b e l t i s believed to have been so prepared, snd i n i t V-shaped v a l l e y s have been transformed i n t o wide, deep "TP1 shaped d e p r e s s i o n s , and hanging v a l l e y s , c i r  ques, roches montormees, snd ether well-known n l a e i s l forms hove been produced," Hanging v a l l e y s fore a very conspicuous feature of the e n t i r e d i s t r i c t . B e a u t i f u l ennnyien arc found on A t l i n moun t a i n , and ir. a l l vntleys. So.xe of those hang lay valleys are at least 2,000 feet above the Lotion, of the :.,ain v c l l e y s . Cirques are a l s o yaite frequent; even i n the lower and 101. s o f t e r contoured i l a t e a u region numerous cirques o f various s i z e are found on almost a l l mountains s t a r t i n g w i t h 5,000 f e e t e l e v a t i o n . In some of them the snow does not i.-.elt the whole sum- mer t v/hile some become sources of s t a l l streams and i n a few cases 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 at the end of the summer. O f p a r t i c u l a r i n t e r e s t are t e r r a c e s which are 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 . Various reasons were advanced f o r t h e i r occurrence. Cairnea 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 denies t h i s because the t e r r a c e s do not seem to have corresponding 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 of the country, and t r i e s to e x p l a i n the formation of t e r r a c e s by the a c t i o n of the i c e i t s e l f . A t l i n D i s t r i c t . General Geology. A grant v a r i e t y of rocks, both sedimentary and igneous and ranging i n are from Pre-Cambrian to Recent, outcrop 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 north of i t i n the Yukon. As the same rocks outcrop both i n the Yukon and the A t l i n d i s t r i c t i t was considered best to adopt the c l a s s i f i c a  t i o n proposed by C o c k f i e l d , as being based on more recent snd d e t a i l e d work. (W. S. C o c k f i e l d and A . II. Bell—h'hltehorae D i s t r i c t , Yukon. G e o l o g i c a l Survey of Canada, Uem. 150.} E r a . Quaternary 103. f a b l e o f Formations. P e r i o d . gonnation. L l t h o l o g l c a l Characters. S u p e r f i c i a l G r a v e l , sand, boulder d e p o s i t s , c l a y , s i l t . , much moraine! m a t e r i a l s , v o l c a n i c ash, s o i l . A c i d .Vol- oanlcs R h y o l i t e , g r a n i t e por phyry, r e l a t e d v o l o a n i c s , w i t h a s s o c i a t e d t u f f s & b r e c c i a s T e r t i a r y lie war v o l  o a n i c s . Andesite, b a s a l t , & r e  l a t e d dyke r o c k s , Chafa- prophyre ?} w i t h assoc i a t e d t u f f 3 & b r e c c i a s . L a * Upper Jur a s s i c or L a t e r . Coast Hange G r a n i t i c rocks ranging I n t r u s i v e s . i n composition from g r a  n i t e to d i o r l t e , wl th a s s o c i a t e d p o r p h y r i t i o phases.  Older v o l - eanles 1'esozoic Lower and l l i d d l e J u r a s s i c Andesite, diabase, b a s a l t , & r e l a t e d v o l e a n i o s with a s s o c i a t e d t u f f s and b r e c c i a s . Tantalus Conglomerate, wi t h sand- conglomer- stone, shale & seams of ate c o a l . Laberge s e r i e s . . . A r g i l l i t e , s h a l e , sandstone, arkose, grey- waoke. t u f f , conglomerate. 103. Table of Formations, (contd. ) I r a . P e r i o d . Formation. L l t h o l o g l e a l Characters. T r i a s s i e Limestone Limestone more or l e a s Cor, and) d o l o a i t i e C a r b o n i f e r - ous(?) _ P a l a e o z o i c Taku group S l a t e s , eherty q u a r t z i t e , Devonian(?) e t c Gold s e r i e s Pyroxenite, p e r i d o t i t e (.IL. Pre- CafflhrianC?) Mount Stevans S e r i c i t e and c h l o r i t e group s c h i s t , mashed basic to semi b a s i c v o l c a n i c s , g n e i s s o i d 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 Stevens Group, fhe Mount Stevens group includes a number of members wide l y d i f f e r e n t i n appearance, composition, and p o s s i b l y i n age. They a r e , however, a l l old and so extremely a l t e r e d that t h e i r mode o f o r i g i n and 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 , 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 o u a r t z i t e s , hornblende g n e i s s e s , and c r y  s t a l l i n e l i m estones. lio f o s s i l s have been c o l l e c t e d from any of the members of the ilount Stevens group and there i s consequently no d i r e c t evidence as to t h e i r age, but from the evidence a f f o r d e d by l a t e r igneous rocks which cut 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 rocks 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 able to demonstrate that the s c h i s t o s e rocks of that r e  g i o n were pre-middle ( ambrian and i n a l l p r o b a b i l i t y i r e - Cambrian In age. The rocks of the group occur i n the westermost part of the d i s t r i c t , close to the contact of the main Coast Range B a t h o l i t h . They outcrop around F a n t a i l Lake, then cross Taku arm below Golden Gate and extend i n a narrow b e l t along Edgar and Tie Is on Lakes to the end of Torres channel, nnd beyond where they f i n a l l y disappear 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 Alaska I n t e r n a t i o n a l Boundary. r l Geol. Surv. Canada, Bern. 67, p. 40-44. 105. Gold Series. 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 general 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 of Pine Creek and then northward, t i l l i t meets the old limestones at head waters of Fourth of July and Consolation Creeks. On one side the formation i s cut by granite of the Leonerd mountain B a t h o l i t h . Smaller masses of these rocks are scattered over the d i s t r i c t . The more important are found on A t l i n fountain 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 features were noted except Jointing and f a u l t i n g , neither of which l a very prominent. Fresh surfaces i n some cases appear granular, and i n others no granular texture i s v i s i b l e . The rock i s dark green to black i n colour. The weathered surface i s coarsely pitted and has a bright-reddish 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 of c h e 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 Cache Creek group of the southern I n t e r i o r of B r i t i s h Columbia. These rocks occupy a l a r g e p o r t i o n of the d i s t r i c t . They are bounded by the £. C. Yukon boundary i n the n o r t h , A t l i n Lake i n the west, l a k i n a R i v e r i n the south and T e s l i n Lake i n the e a s t . In the c e n t r a l p a r t the s e r i e s i s cut 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 areas o f limestones, v o l c a n i c s , and the Gold s e r i e s . Harrow b e l t s occur on the west side o f A t l i n Lake. The members of the Taku group are mainly c h e r t s , and s l a t e s . 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 places they are reddish on weathered s u r f a c e s , due to o x i d a t i o n of small amounts of contained i r o n ore. The rocks are massive, hard, nnd b r i t t l e and break i n t o sharp edged, i r r e g u l a r l y shaped fragments. The rooks of the Taku group u n d e r l i e the Carboniferous (?) Braiburn limestones and appear to correspond w i t h the members of Lower Cache s e r i e s , of more southerly p o r t i o n s of B r i t i s h Columbia; they have t h e r e f o r e been considered to be probably o f Devonian age. {Cairnes, D. D., Geol. Surv. of Canada, I em. 37, p. 53-53) ( G w i l l i m , J . C. "Report on A t l i n Mining D i s t r i c t , ! f G.5.C. Ann. Rept. V o l . I l l , p t . B, p. 17) 107, Braeburn Limestones, "Braeburn limestones occupy the entire northeastern corner of Taku Arm b e l t and are extensively 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 southeasterly 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 generally f i n e l y textured and range i n colour from greyish blue to a 1, oat white. The name *Breeburn limestones'' was f i r s t applied i n the Braeburn- i Kynocks area, '" from where these rocks have been traced contin uously to Taku Arm b e l t . These limestones are also the same as those included under the Upper Cache Creek series of Conrad mining d i v i s i o n . Dr. Dawson collected F u a i l i n a e from the limeatones which extend along the east s i t e of 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 are, 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. Cairaes, 1'em. 37. G. S. C. P.53. % Cairnes, D. D. "Preliminary memoir on the Lawes end Bor- d e n s k i o l d Rivers coal d i s t r i c t , Yukon T e r r i t o r y . " Geol. Surv. , Dept. of tlines, Can. Mem. ho.5, 1910, p, 28-30. 108. Laberge S e r i e s . The Laberge a e r i e s i s the most extensive g e o l o g i c a l terrane i n Taku Arm b e l t , ana i t s members outcrop i n a general way throughout the c e n t r a l , southwestern am 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 east o f Taku arm and south of Graham I n l e t ; the g r e a t e r p a r t of the area north of F a n t a i l Lake and south of T u t s h i Lake, on the west side o f Taku arm; and Sunday mountain ana the western p o r t i o n of Taku mountains, are a l l l a r g e l y composed of these r o c k s . The Tantalus conglomerates nre probably best included w i t h the Laberge s e r i e s , because they o v e r l i e the Laberge rocks conformably. I n Wheaton d i s t r i c t , where the most d e t a i l e d work done i n the d i s t r i c t was undertaken, and where the best expos- i ures of t y p i c a l l y marine sediments 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 , or i f , as i n the present case, the Tantalus conglomerate \*> i n c l u d e d , a f o u r f o l d d i v i s i o n : Tantalus conglomerate; thickness 1,800 f e e t . - Conglomerate, s h a l e , sandstone, and c o a l , Laberge S e r i e s ; TJpper beds; thickness 1,500 f t . sandstone Middle ; * 1,700 f t . s h a l e s , s.s., arkose. Lower "» ; 1 1,800 f t . arkoses & t u f f s w i t h „ shales 3 conglomerates. t o t a l 6,800 f t . * C a i r n e s , D. D. '^heaton D i s t r i c t ' 1 G.3.C. Mem. 31, p. 54-56. 109. F o l l o w i n g C o c k f i e i d : — ''Fossils 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 Tantalus areas. In 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 , three forms aere 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 , Ilerinea mandensis, and Rhynchonella O r t h i d i o i d e s . The specimens were regarded by . v/hit eaves as J u r a s s i s o r Cretaceous but two I f not a l l three of these s p e c i e s are now regarded as J u r a s s i c forms. F o s s i l s c o l l e c t e d by G w i l l i m In A t l i n d i s t r i c t were reported 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 c , but 1 th i n k i t more probably that they are e a r l y J u r a s s i c . They are 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 very 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 to lower f i d d l e J u r a s s i c . r G w i l l i m , J . C ; G. S. C. Ann. Rept. V o l . I l l , p t . 3, p. 23-27 (1899). ^ w» E« C o c k f i e i d and A* H. B e l l . "Whitehorse D i s t r i c t , Yukon. t T G. S. C. Kern. 150, p. 2 2 . 110. Older Volcanics. These rocks are t y p i c a l l y compact, f i n e l y textured, and dark green, hut red, brown and blue types also occur. They are p r e v a i l i n g l y porphyrl t i c , with feldspur c r y s t a l s 1/8 inch or more i n length, in an aphenitic ground eass. The older volcanics extend as a belt 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 into the Perkins 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 subdivision was dropped, and the rooks were correlated with the older volcanics o f White River d i s t r i c t . Portions of the older volcanics are d e f i n i t e l y i n  trusive into the Laberge beds, and may therefore be considered younger. Cockfieid considers them to be Lower or I'iddle Jurassic. Cairnes,, D. D. ^Upper White River D i s t r i c t , G. S.. £. Kern. 50, p. 87-93. Cairnes, D. D. G.S.c. Sum. Rept. 1915. 111. Coast Range I n t r u s i v e s . The western p o r t i o n o f the d i s t r i c t i s occupied by the Coast Range i n t r u s i v e s . Besides the l a r g e r areas a number of sm a l l e r exposures occur i n v a r i o u s l o c a l i t i e s through the d i s  t r i c t . Apparently a l l these g r a n i t i c masses are a part of 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 are f o r the most part f r e s h and u n a l t e r e d i n appearance, a r e predominantly g r e y i s h i n c o l  our, and have the gen e r a l appearance of t y p i c a l , medium to co a r s e l y t e x t u r e d g r a n i t e s * 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 to give these rocks 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 . I n places these 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 co n t a i n numerous l a r g e f e l s p a r phenoerysts as much as l£ to 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 contains no quartz, approaching true d i o r i t e i n composition. Hornblende, b i o t i t e and auglte are g e n e r a l l y present and ore i n most cases r e a d i l y v i s i b l e to the unaided eye. As found by l a t t e r work of D. D. Cairnes and 1 . d. C o c k f i e i d the i n t r u s i v e s cut Laberge s e r i e s and even Tantalus conglomerate. Cairnes at f i r s t ma mislead by the f a c t t h a t the Laberge beds c o n t a i n d i o r i t i c pebbles 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 si n c e rocks o f lower Palaeozoic age c o n t a i n i n g d i o r i t i c pebbles have been found on the Alaskan 112. c o a s t , t h i s i s no longer an argument to suppose that the B a t h o l i t h was intruded i n pre Laoerge time. I t i s much s a f e r , concludes C o c k f i e l d , to consider the Coast 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© rocks which they c u t . From t h i s i t seems that the i n t r u s i v e s are not e a r l i e r than the lower part o f the middle J u r a s s i c . The B a t h o l i t h may be regarded as Upper J u r a s s i c or l a t e r . Hewer V o l c a n i c a. Small areas near the town o f A t l i n , i n the v a l l e y s of Ruby Creek and other creeks d r a i n i n g i n t o S u r p r i s e Lake, and f a r t h e r north i n the v a l l e y o f S i l v e r Creek are covered with very recent l a v a s . Some of these o v e r l i e g o l d bearing; g r a v e l s . The l a v a s are T e r t i a r y and quaternary i n age. In ge n e r a l 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 springs and mi n e r a l s p r i n g s are found i n s e v e r a l places 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 a f t e r v o l c a n i c a c t i o n . Recent Sediments. Those are mostly found i n the v a l l e y s , and are made of coarse sands of g r a n i t i c o r i g i n , and g r a v e l s of g l a c i a l end post g l a c i a l o r i g i n . In the v a l l e y s of some of the creeks the g r a v e l s are u n d e r l a i n by "hard pan" made of 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 . In plaees 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 gold b e a r i n g . The g r a v e l s i n Pine Creek V a l l e y cover the p e r i d o t i t e s and pyroxenites of the gold s e r i e s . 113 Keqnomlc Geology* A t l i n D i s t r i c t . For q u i t e a w h i l e a f t e r i t s establishment i n 1896 as a g o l d producing camp, A t l i n d i d not pay much a t t e n t i o n to any t h i n g but p l a c e r g o l d d e p o s i t s , but i t i s easy to change from plac e r g o l d prospecting 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 the metal, and so t u r n to quartz prospecting. P r o s p e c t i n g and g e o l o g i c a l work done i n the d i s t r i c t by P r o f . G w i l l l r a i n 1901, have shown that the d i s t r i c t i s unusually favourably l o c a t e d , f o r occurrences o f ore d e p o s i t s . Several t^pea o f deposits are found, and are c l a s s i f i e d by D. D. Cairnes 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 quartz 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 g o l d veins (d) s i l v e r lead veins (e) copper veins ( f} antimony veins. (g) contact metamorphic d e p o s i t s . I t 13 c l e a r l y seen from the l i s t , that to produce such a d i f f e r e n c e i n types of ore d e p o s i t s , eonsideraole 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 indeed, i n examples of various 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. 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 , and the varying i n f l u e n c e s of sedimentarles and v o l c a n i c s . I t i a t h e r e f o r e c l e a r that a v a r i e t y of chemical and p h y s i c a l c o n d i t i o n s was a v a i l a b l e f o r the formation of these d i f f e r e n t types o f d e p o s i t s . I t seems almost impossible to g e n e r a l i z e f o r tne d i s  t r i c t as a whole, except may be, that m a j o r i t y of d e p o s i t s seem to be connected .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 , and 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 . The s m a l l e r B a t h o l i t h s may or may 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 the Batho l i t h s are s i m i l a r , and that t h e r e f o r e i t i s probable that they are o f the same age. In d e s c r i b i n g the d e p o s i t s o f the D i s t r i c t I intend to f o l l o w i n general way Cairne's p l a n , I.e., describe them by types, but adding new i n f o r m a t i o n , added since Cairnes has 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 . These changes w i l l apply p a r t i c u l a r l y to the Engineer Gold B i n e s , and the t t l i n Huffner Mine, s i n c e these p r o p e r t i e s r e c e i v e d considerable amount of a t t e n t i o n during the l a s t y e a r s , while very l i t t l e work was done on the r e s t . One notable exception among the mineral deposits of A t l i n D i s t r i c t i s the a t l i n Huffner Mine. This deposit i s d e f i n i t e l y post J u r a s s i c , and 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 property w i l l be found f a r t h e r down, but i t might be . i/ell to state the g e n e r a l reasons f o r p l a c i n g the formation of tne deposit as Post J u r a s s i c . XX 5 • fhe country rock, I s the t y p i c a l quartz d i o r i t e or g r a n o d l o r i t e o f J u r a s s i c age. This g r a n o d i o r i t e was f i s s u r e d by eorapressional s t r e s s e s , apparently a c t i n g during the Laramide R e v o l u t i o n . The f i s s u r e s ;ere then T i l l e d >;Ith Lamprophyre and quartz porphyry, ^ 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 again, 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 period could h<.ve occurred only 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. A t l i n D i s t r i c t . _o. Geology. General. fype of Deposit* Occurrence. Age? l i n e r a l a s s o c i a t i o n . Gold T e l l u r i u m Engineer Mine. Juras8io Laberge s e r i e s , a r g i l l i t e s , grey- waeke^s J u r a s s i c batholith Q u a r t z , c a l c i t e , m a r l p o s i t e gol d Gold S i l v e r Vein i n hornblende Happy S u l l i v a n d i o r l t e Q u a r t z , c a l c 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 C u p r i f e r o u s i n Andesite o f S i l v e r Gold Veins J u r a s s i c ->ge. The P e t t y Group J u r a s s i c .^uartz, c a l c i t e , galena, chaleo p y r i t e . p y r i t e , m a lachite. S i l v e r Lead Dykes i n quartz Veins. D i o r i t e and A t l i n Euffner Mine D i o r i t e Post J u r  a s s i c , pos s i b l y Ter t i a r y Copper Veins O l i v i n e b a s a l t s J u r a s s i c q p t z , c a l c i t e , galena,a phaler- i t e , p y r i t e , p y r r h o t i t e , a r  senopyri te , ruby s i l v e r c a l c i t e , n a t i v e copper ,iaalachi t e , c u p r i t e . Antimony Veins Shales o f La- berge s e r i e s . Probably J u r a s s i c q u a r t z , s t i b n i t e , galena. Contact Meta- morphic Depo s i t s . I.;t. Stevens Pre Cambrian J u r a s s i c magnetite,hema t i t e . c haleopyrite t e t r a h e d r i t e , e r y t h r i t e . y e l l o w g a r n e t , f a i o t i t e . 117. GoId-Tellurium V elna. General. G o l d - t e l l u r i u m quartz veins have been discovered i n A t l i n d i s t r i c t i n only one l o c a l i t y which i s s i t u a t e d on the east s i d e o f Taku arm. above Golden Gate. The g r e a t e r number o f the veins occur a t the Engineer mines where the bulk o f the r i c h ore i n t h i s type 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 also been d i s  covered on the a d j o i n i n g c l a i m s . The Engineer Mines. # taken from. c o n f i d e n t i a l report to the Mine Manager by Dr. ./. E. C o c k f i e i d . The author v i s i t e d the mine and recheoked a l l the observations a year l a t e r . 118. fhe Engineer Mine. by tf. S. C o c k f i e i d . fhe Engineer Mine i s s i t u a t e d on f a g i s h L<«;e, ap p r o x i  mately 12 miles south o f Golden Gate, where the route to A t l i n turns to the e a s t . This property has been known f o r a long time and has f r e q u e n t l y aroused i n t e r e s t on account o f i t s s p e c t a c u l a r g o l d showings. fhere has, however, been comparatively l i t t l e w r i t t e n w i t h regard to the geology o f the property i n recent y e a r s . The e a r l i e r developments are described by Cairnes and des c r i p t i o n s o f the property have a l s o been given i n the annual r e p o r t s of the 3. 0. M i n i s t e r of Mines, a few years ago the f i r s t attempt was made to mine t h i s property on a l a r g e s c a l e and a great deal o f money aas spent on the development o f the mine and In Improvements to tne'eamp, but the veins c o n t a i n i n g the high trade ore d i d not f u r n i s h s u f f i c i e n t tonnage to Jus t i f y operations on the s c a l e on which they were attempted and the venture ended i n f a i l u r e . Since that time a s m a l l crew has been working 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 ore which nas been i n d i c a t e d by some of the development c a r r i e d out on the high grade v e i n s , l a t e l y the property has been c l o s e d down due to 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 that i t w i l l be re-opened at an e a r l y date The country rock i n the v i c i n i t y of the Engineer L i n e c o n s i s t s o f J u r a s s i c a r g l l l i t e s , greywaekes, e t c . , belonging to Ca i r n e s , D. D. Geol. Surv. Canada, kern. 37, p. 73 - 89. 119. the Laberge s e r i e s . These are p i e r c e d some distance back o f the property by a stock o f g r a n o d i o r i t e which forms Engineer Mt. On the property i t s e l f and towards I t s southern end are two s m a l l outcrops o f g r a n o d i o r i t e , apparently part o f tne same stock which has been barely deroofed. The v e i n system i a i n t r i c a t e and i t Is l a r g e l y because o f the amount o f development work which has been done by Engi neer Mines L t d . that the r e l a t i o n s show as c l e a r l y as they do. In th® c e n t r a l part o f the property are two Hubs o f q u a r t z ; one o f these being s i t u a t e d 200 f t . east from the shore.of the l a k e , and the other about 1,400 f t . east of the f i r s t . These are known as Hubs "A" and "B" r e s p e c t i v e l y . Hub "A" i s the l a r g e r o f the two and Is approximately £40 f t . long by 160 f t . wide, and i s composed o f a number o f veins o f quartz o f country rock and i n c l u d e d country rock; the whole forming a stockwork. Hub "B" i s approximately 120 x 80 f t . , and i s s i m i l a r i n c h a r a c t e r to Hub ",«.". There zones h.ve been e x t e n s i v e l y t e s t e d , but so f a r have not been proved to c a r r y commercial value s . There are a l s o a number of veins which were o r i g i n a l l y thought to r a d i a t e out from tnese nubs but more recent work tends to throw some doubt on t h i s theory. The p r i n c i p a l veins are tne Double Decker, Engineer, Jersey L i l y , Boulder, uidy, and Blue v e i n s . I n a d d i t i o n there are a uur.iber of others whloh have been more or l e s s neglected i n the recent developments. Running from tne g r a n o d i o r i t e outcrops near tne south end o f the property towards Hub "a", tnere i s a shear zone waioh i s marked on the surface by a pronounced topogr^puic depression 120. and which l a w e l l shown i n the underground workings. Instead o f the w i n s r a d i a t i n g out from the Hubs of quartz p r e v i o u s l y mentioned. I t would appear t h a t they are connected w i t h t h i s zone o f s h e a r i n g from which they appear to be given o f f at d i f  f e r e n t a n g l e s . This shear zone d i v i d e s the veins i n t o two groups—-the Double Decker, Engineer and Jersey L i l y v eins l y i n g to the west, and the boulder, Andy and Blue veins l y i n g to tne east o f t h i s zone. I t s r e l a t i o n to the veins i s not q u i t e apparent; none of the veins have been traced i n t o the shear or across I t . They a l l apparently s t a r t a s h o r t d i s t a n c e from t h i s zone. There are two s e t s o f dykes on the property. One o f these i s roughly p a r a l l e l to the d i r e c t i o n o f the shear zone and the other roughly p a r a l l e l to the Engineer and Double Decker v e i n s . These dykes are 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 contempor aneous. On account of the l a c k o f outcrops 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 ould not be d e f i n i t e l y determined but n e i t h e r s e t o f dykes apparently o f f s e t s the o t h e r . Both s e t z o f dykes are o l d e r than the v e i n system. This i s e a s i l y seen from the underground workings where the dykes are cut and o f f s e t by the v e i n s . In places the dykes are h e a v i l y impregnated w i t h p y r i t e . The veins 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 to two f e e t or more i n t h i c k n e s s . The b e t t e r ©ineralized parts o f the veins are i n many cases only 6" to 8" t h i c k . Most of the veins are f i l l e d w ith quartz. 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 workings 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 workings at the present time c o n s i s t o f the f i f t h , s i x t h , seventh 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 entry to the mine. This l e v e l has been d r i v e n from a p o i n t somewhat over 100 f e e t above the l a k e l e v e l , and was at the time of the w r i t e r f s v i s i t 1450 f e e t l o n g . This a d i t encounters the Double Decker vein,at 625 f t . , and the Engineer Vein a t 1185 f t . and was being con tinued to i n t e r s e c t the shear zone. From the point where the a d i t encounters the Double Decker v e i n , a d r i f t has been run on t h i s v e i n 640 f t . i n southwesterly d i r e c t i o n and 360 feet i n a n o r t h e a s t e r l y d i r e c t i o n , and i s continued i n t h i s d i r e c t i o n to c r o s s c u t the shear zone. Throughout t h i s d i s t a n c e the v e i n 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 f r e e g o l d . Occasional s p e c t a c u l a r values are encountered-. The g o l d apparently f o l l o w s cracks and e r e v i c e s i n the q u a r t z . The Engineer Vein has been d r i f t e d on 1100 f e e t south west fro® the a d i t and E£0 f e e t northeast. This l a t t e r d r i f t Is continued as a c r o s s c u t through the Jersey L i l y v e i n , the shear zone, and to the iindy, Boulder and Blue veins 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 three v e i n s . From the southwest d r i f t a s h a f t has been sunk to the 800 foot l e v e l w i t h intermediate l e v e l s at 600 and 700 f e e t . The Engineer Vein ranges i n width from a seam to n e a r l y two f e e t . I t d i f f e r s from the other veins o f tne property i n being m i n e r a l i z e d w i t h c a l c i t e , m a r iposite (chrome micaft a l l e m o n t i t e (a compound of n a t i v e a r s e n i c and n a t i v e antimony) and f r e e g o l d . The gold Is 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 Boulder v e i n where cut by the 500 foot l e v e l i s 4 f e e t wide and has been d r i f t e d on f o r 600 f t . I t maintains t h i s width over a c o n s i d e r a b l e p a r t of t h i s d i s t a n c e . I t con 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 country rock and c a r r i e s In spots high values i n g o l d . I t l i e s on eastern side o f the f a u l t zone and tronds away from i t at an angle o f 30 degrees. The Andy and Blue v e i n s are somewhat s i m i l a r to Double Decker v e i n . 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 surface o f 400 f t . , but was not v i s i t e d i n the underground .workings owing to v e n t i l a t i o n d i f f i c u l t i e s . These veins do not, so f a r as i s known, c o n t a i n the s p e c t a c u l a r values found i n some of th© other v e i n s . The Jersey L i l y v e i n from surface and underground workings has an I n d i c a t e d l e n g t h of 1400 f t . but i t has not been traced continuously over t n i s d i s t a n c e . I t i s i n c l i n e d to the o f a u l t zone at 30 towards the southwest. I t a l s o does not, so f a r as known, c o n t a i n spectacular values i n g o l d . The workings below the 500 l e v e l are f u l l o f water and consequently could not be examined. The f o l l o w i n g i n f o r m a t i o n , 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 Engineer v e i n has been d r i f t e d on f o r 160 f t . S.i/. from the s h a f t and f o r 80 f t . Ji.E. from the s h a f t . On the 700 foot l e v e l the Engineer Vein has been d r i f t e d on f o r 260 f t . S.tf. from the s h a f t and 320 f t . II.fi. On the 800 foot l e v e l the Engineer Vein has been d r i f t e d on 320 f e e t S. W. from the s h a f t and f o r 280 f t . northeast from the s h a f t . 123. I n these workings t h i s v e i n shows e s s e n t i a l l y tne same charac t e r i s t i c s as to width and m i n e r a l i z a t i o n as i n the upper l e v e l s . On the 800 foot l e v e l there i s a cro s s c u t 380 f t . long to the 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 to the northeast o f 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 widening on. the 800 l e v e l where i t has an average width o f Z f e e t and a maximum o f about f o u r f e e t . This d r i f t continues u n t i l i t cuts the shear zone and from i t the shear zone has been d r i f t e d on for 330 f t . to the northwest and f o r 500 f t . to the southeast, the d r i f t being only p a r t l y i n the shear zone and l a r g e l y i n the dyke which accompanies i t * The shear zone Is one o f the most important features o f the p r o p e r t y , AS i n d i c a t e d by the topography i t i s q u i t e per s i s t e n t and underground i t has been opened at s e v e r a l p o i n t s . On the 500 foo t l e v e l i t i s crossed by the Double Decker and Engineer d r i f t s and on the 800 l e v e l by the Doable Decker d r i f t . At each p o i n t where cut by the underground workings i t i s w e l l m i n e r a l i z e d w i t h quartz 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 width o f t h i s zone v a r i e s ; but I n c l u d i n g the dyke, which i n many oases accompanies I t , Is as much as 65 f e e t wide. Of t h i s 20 to 28 f e e t i s w e l l m ineral i z e d with quartz and p y r i t e . Good values have been i n d i c a t e d over widths o f 6 to 14 fee t w i t h lower values over the whole zone. 124* fhe property has 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 may he d e f i n i t e l y stated 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 to maintain a l a r g e o p e r a t i o n , yet there i s s u f f i c  i e n t to permit the property to be worked In a s m a l l way. The d e f i n i t e widening o f the Double Decker v e i n on the 800 l e v e l and the widening o f the Boulder v e i n on the 500 l e v e l i n d i c a t e t h a t there may be a p o s s i b i l i t y of the veins I n c r e a s i n g In width w i t h depth. The increase i n width so noted have not been accompanied by a d e f i n i t e trend toward lower values. Further the Doable Decker and Engineer veins are I n c l i n e d so that i f ' t h i s a l t i t u d e be continued 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 tha 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 width o f ore w i l l be encountered, A l a r g e part of t h i s shear zone ha3 not been explored. I t has an i n d i c a t e d l e n g t h o f about 4000 feet and may be much longer and as t h i s shear zone was l i k e l y the main c i r c u l a t i n g channel 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 there i s a p o s s i b i l i t y of concentrations o f ore along I t which might supply the necessary tonnage to make the property a success. The values i n d i c a t e d i n places are encour aging and 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 r e s u l t s a l r eady obtained. Any f u r t h e r work which Is done on t h i s property w i l l 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 that such shear zones would occur s i n g l y . As there 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 of high grade gold ores, there i s a p o s s i b i l i t y t h a t these occur i n connection w i t h s i m i l a r zones of s h e a r i n g . I f the zone on the Engineer can be proved to curry ore bodies of 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 than has been the case i n the past. 126. G o l d - S i l v e r T y p e . S e v e r a l ore deposits i a the d i s t r i c t belong to t h i s type, and have been found at a number of p o i n t s , the most im port a n t of whieh a r e ; White Moose, Rupert and Happy S u l l i v a n groups on the Taku arm* the Lawson group on Bighorn Creek; a t the Beavls Mire near the Town of A t l i n ; - the Imperial l i n e on Munrae Mountain east of A t l i n ; and on the Brothon and A l v l n e c l a i m s on Haboe Creek near the Lead o f Torres Channel, an arm of A t l i n Lake. G e n e r a l l y these v e i n s cons i t mainly of qu a r t z , but some a l s o c o n t a i n c a l c i t e as an associated gangue m i n e r a l . Galena and p y r i t e are the most common m e t a l l i c minerals but 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 occur, and nat i v e gold 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 are g e n e r a l l y o f va 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 or l e s s s i l v e r which i n places even exceeds gold 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 are l o c a t e d on the Munro Mountain, some 5 m i l e s from the town of A t l i n . A good automobile road i s fol l o w e d f o r 4 m i l e s to Half-way Rouse on Pine Creek, and from there a t r a i l to the foot o f Munro Mountain. The author v i s i t  ed the mine i n 1931, but as the workings were h a l f caved i n no # Robertson,W.F., Report o f the M i n i s t e r o f I'ines, B.C. 1900-04. G w i l l i f f i , J . C . "Report on the A t l i n Mining D i s t r i c t , E . G . * G.S.C, C a i r n e s , D. D. G.S.C. Mem, Ho. 37. 127. attempt was made te 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 follows: *-—The entrance to the lower tunnel i s 1030 feet i n elevation above A t l i n whsrf — " " A l l work at these mines has been expended i n develop ing a single quartz lode which occurs i n a finely-textured rock that ranges from hornblende-diorlte to a hornblende-diorite porphyrite. The lode s t r i k e s H. 70° E* and dips et angles of •n O 50 to 60 to the southeast. This deposit includes two or three close, p a r a l l e l , mineralized f i s s u r e s which contain an aggregate thickness of £ to 3 feet of vein material consisting mainly of quartz, sparsely d i s t r i b u t e d through which are p a r t i c l e s of galena*, chaleopyrite, p y r i t e , malachite, and occasionally, native gold. A considerable portion of the quartz i s thought to contain from £10 to $30 per ton in gold and s i l v e r , the s i l v e r being re l a t i v e l y small i n amount. Two cross-cut tunneIs have been driven, which tapped the vein at 25 and 112 feet respectively, and from these over 400 feet of u r i f i s have been driven. 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 tex tured, rock that i s either megascopically e n t i r e l y aphanitic or contains v i s i b l e hornblende phenocrysts i n an aphanitic ground- mass, and ranges from a hornblende d i o r i t e to a hornblende- d i o r i t e porphyrite. Under the microscope a t y p i c a l sample v 128. proved to be composed l a r g e l y o f p l a g l o c l a a e and pale brownish hornblende, w i t h some accessory i r o n o r e , the hornblende occur r i n g i n shreds and I r r e g u l a r p r i s m a t i c forms Imperfectly t e r  minated and c o n s t i t u t i n g nearly h a l f of the rock mass. Be s c r i p t i o n of V e i n s . — A l l the work on these claims has been expended i n developing one main v e i n or lode which s t r i k e s o o o approximately 1. 70 11., d i p s from 50 to 60 to the S.S., co n t a i n s where i t has been exposed, from 1 to 7 f e e t o f v e i n - m a t e r i a l , and has been traced f o r a distance o f over 500 f e e t . The v e i n i s not simple i n form but i n c l u d e s , i n moat p l a c e s , the quartz and a s s o c i a t e d minerals which have been deposited 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 also replaced more or l e s s o f the o r i g i n a l i n t e r v e n i n g w a l l rock. The v e i n i s thus a compound v e i n , or si n c e replacement has been e f f e c t i v e to a cons i d e r a b l e degree i n a l t e r i n g the intervening; and I n t e r c a l  ated rock p o r t i o n s , the term lode i s probably most a p p r o p r i a t e . On account o'f i t s compound nature t h i s v e i n n a t u r a l l y v a r i e s 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  tutes t h i s lode i s f a i r l y p e r s i s t e n t ; but the various small included members are q u i t e e r r a t i c and i n most pl a c e s the lode i s d i v i s i b l e i n t o two or 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 to have an average thickness of from 2 to 3 f e e t and c o n s i s t s mainly of quartz which i s of t e n i r o n s t a i n e d o r rose co 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 129. t r u s t i f i c a t i o n and comb structures, but i s a l s o in places quite massive in 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, chalcopyrite, p y r i t e , malachite and f r e e g o l d . Pockets or shoots oc c u r , however, in 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 silver property i s the Happy Sullivan Mine. Minister of Mines Report, 1930. k 130. M i n i s t e r o f Mines Report, 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 Clarence 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 about 3 m i l e s n o r t h of the Engineer and about 2 m i l e s from the south end of Taku Arm, Tagish Lake. The claims are at a l t i tude 3700 f e e t on the north side of Sheep Creek and about 2 m i l e s from the shore o f the l a k e . The ore occurrence 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 gold v a l u e s i n quartz s t r i n g e r s , o c c u r r i n g i n bed ded sandstone o f the Laberge s e r i e s of Lower or K i d d l e J u r a s s i c age. Surface trenching ana a l i m i t e d amount of t u n n e l l i n g c a r r i e d out under former optio n ere not conclusive regarding the p o t e n t i a l i t i e s o f the property. 131. A t l i n D i s t r i c t . Economic Geology. Ca p r i f e r o u s S i l v e r Gold Veins. Ge General. The veins considered under t h i s heading have been found i n A t l i n D i s t r i c t on Table mountain which i s s i t u a t e d on the north shore o f Graham I n l e t opposite Taku Landing. The only two d e p o s i t s on t h i s mountain that have been at a l l developed occur on the P e t t y and Dundee groups r e s p e c t i v e l y , and occur i n granite-porphyry which 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 ande- s i t e s and a n d e s l t i c t u f f s . The vei n s c o n s i s t mainly of quartz, o a l e i t e , galena, c h a l e o p y r i t e , p y r i t e , m alachite, and a z u r i t e , which minerals occur a l s o to some extent disseminated through the w a l l r o c k s . The P e t t y v e i n where exposed i s from 6 inches to 2 f e e t i n thickness and has been traced f o r over 100 f e e t ; the Dundee v e i n has a maximum known th i c k n e s s o f 2.5 f e e t , but has not been followed more than 50 f e e t . The P e t t y Group. The Petty group c o n s i s t s o f two claims which are s i t  uated on the southeastern corner 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 are about 3_r mi l e s i n north-westerly d i r e c  t i o n from Taku Landing. The rock formation i n t h i s v i c i n i t y c o n s i s t s mainly of the C h i e f t a i n H i l l v o l c a n i c a which are here p r e v a i l i n g l y green i s h andesites and a n d e s i t i c t u f f s . These have been e x t e n s i v e l y invaded by dykes o f granite-porphyry, belonging to the KJuaha i n t r u s i v o s . (D. D. Cairnes, G.S.C, Mem. 37, p. 106). 132. Only one main v e i n has been so f a r e x p l o i t e d on the Petty group, and t h i s occurs i n the'granite-porphyry, s t r i k e s o o H. 30 S. and has on average d i p o f about 40 to the northwest. The v e i n c o n s i s t s mainly o f q u u r t z 7 e u l c i t e , galena, chaloopy 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 , and one small c a v i t y was found to 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 the ra r e mineral l i n a r i t e (a b a s i c sulphate o f l e a d and copper). The quartz i s g e n e r a l l y r u s t s t a i n e d and occurs assoc 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 places even exceeds quartz i n amount. Galena aud c h a l e o p y r i t e are tne most abundant ore minerals present, and occur in- approximately equal amounts and i n s u f f i c i e n t q u a n t i t y i n places to c o n s t i t u t e the g r e a t e r p o r t i o n of the v e i n - m a t e r i a l . This v e i n has a t h i c k  ness, at the widest point so f a r d i s c o v e r e d , o f about 2 f e e t , but r a p i d l y diminishes to 6 inches or l e s s w i t h i n a dis t a n c e o f 50 feet i n each d i r e c t i o n , and has not been followed f o r over 100 f e e t . I t i s p o s s i b l e , however, that f a r t h e r development may show the v e i n to extend a somewhat gr e a t e r d i s t a n c e . I n a d d i t  i o n , s e v e r a l other m i n e r a l i z e d f i s s u r e s occur i n places 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 the rock between these i s to some extent 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 that at the main s h a f t the ore might be considered to have a t o t a l t h i c k n e s s o f 3 f e e t at the s u r f a c e , but towards the bottom o f the s h a f t I t s thickness Is much l e s s . The ore i s claimed to c o n t a i n four or f i v e d o l l a r s per ton i n go l d , w i t h the main 133. Tallies i n s i l v e r and copper; bat so few t e s t s have been made, that I t i s u n c e r t a i n what average amounts of these metals the ore c a r r i e s . " Th& Dundee group c o n s i s t s o f 2 adjacent claims to the P e t t y group and I t s geology i s very s i m i l a r to the above. 134. A t l i n D i s t r i c t S i l v e r Lead Veins. As an example o f the s i l v e r l e a d type of deposit i n tne A t l i n D i s t r i c t , the A t l i n Ruffner 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 author spent two summers on the property, and i t was th e r e f o r e deemed best 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 the mine, as presented to the mine manager. Hut as the r e p o r t deals only w i t h tne geology of the mine proper, a few words have to be added i n regard to l o c a t  i o n , and ge n e r a l geology. The A t l i n Ruffner Mine i s l o c a t e d on Leonard Mountain, b e t t e r known l o c a l l y as the fanghan f o u n t a i n . Surface Geology. The Vaughan Mountain i s one of a s e r i e s of peaks, com p r i s i n g a range running i n a general II. or S« d i r e c t i o n . This range g r a d u a l l y lose3 height towards A t l i n Lake. The Range i s separated from other 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 to the East. The main p o r t i o n of the Vaughan or Leonard mountain l a made of coarse 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 of f i n e - g r a i n e d d i o r i t e . Both the q u a r t z - d i o r i t e and the D i o r i t e are out by a s e r i e s o f p a r a l l e l lamprophyre dykes and another 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 dip 135. 0 o from 65 - 70 S. West. fhe b a s i c dykes vary considerably i n s i z e , from a few inehes to about 40* i n w i d t h . As f a r as i s known they run con t i n u o u s l y f o r a d i s t a n c e o f s e v e r a l m i l e s . The dykes, espec i a l l y the l a r g e r ones, can e a s i l y be t r a c e d , because o f abundant f l o a t , frequent outcrops, and troughs 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 general has been c o n s i d  erable , and i t represents an o l d and p a r t l y eroded g l a c i a l c i r q u e . The mountain was step f a u l t e d at a comparatively recent date, .and i n some places very good f a u l t escarpments can be observed. This i s t r u e o f nearby country as w e l l , and i s probably best shown on the neighboring Steamboat t i n t , wnere the scarps are very w e l l preserved.T The surface o f the mountain i s covered w i t h a great q u a n t i t y o f loose boulders, which hide the rock underneath. This made i t impossible to determine a c c u r a t e l y the quartz- 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 only p o s s i b l e to draw an a r b i t r a r y l i n e , w i t h i n 100* of the true c o n t a c t . 136. The d i s t a n c e by automobile road 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 of the 4th 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 opposite banks. (V*. J . O k u l i t c h . "1931 Geology o f A t l i n Ruffner Mine." r e p o r t of the Mine G e o l o g i s t . ) 137, GEOLOGY. Gene ra 1 Ge o l ogy. The examination o f the mine, the |100 and 4300 workings, and the su r f a c e geology from 4100 I'.X.C. to beyond the C r a t e r Creek has shown t h a t ; 1) The country rock Is a coarse grained hornblende q u a r t z - d i o r i t e . T h i s rock i s the same i n 4100 M.I.C. i n the 4300 l e v e l , the 4500 l e v e l , and the s u r f s ce from the main c r o s s  cut to beyond C r a t e r Creek. The s i z e of g r a i n v a r i e s somewhat but i s e s s e n t i a l l y the same throughout. The rock seems to be composed o f p l a g i o - c l a s e , Hornblende, q u a r t z , and B i o t l t e i n subordinate q u a n t i  t i e s . Orthoclase i f p r e s e n t , can not be sepsreted from the other f e l s p a r by examination of hand specimens. Therefore i t i p o s s i b l e that the rock may be ( i n case o r t h o c l a s e i s present) 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 jby Dr. J . T, ¥andy, t h a t the rock i s a q u a r t z - d i o r i t e r i c h i n hornblende. This type of rock 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 country rock are patches of darker and f i n e r grained m a t e r i a l r e p r e s e n t i n g the more b a s i c phases. At about 6000 f e e t e l e v a t i o n the country rock changes from q u a r t z - d i o r i t e to true hornblende d i o r i t e . T h i s rock i s much f i n e r g r a i n e d . I t was impossible due to g r a v e l and boulder cover to determine the contact 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 the p o s s i b l e contact zone to about 100 f e e t each way. The centsct apparently passes j u s t 138. above EC Shaft ana runs southward, passes Just below 4 M tunnel snd continues s o u t h , c r o s s i n g the Fourth of J u l y V a l l e y somewhere .In the v i c i n i t y of the F i r s t Canyon o f the Creek. The other g r a n i t e rock, the true 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 of the Canadian G e o l o g i c a l Survey has not been found anywhere i n place and must have been brought to the Vaughan Mountain by i c e . I t should be n o t i c e d that a change i n country rock, from q u a r t z - d l o r l t e to d i o r i t e /nay or may not have an e f f e c t on ore d e p o s i t s . What i n f o r m a t i o n we have from the 411 tunnel seems to p o i n t that galena i s more massive, and there i s l e s s s p h a l e r i t e and a r s e n o p y r i t e . But t h i s point has not been prov en d e f i n i t e l y y e t . 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 basic dykes s t r i k i n g n o r t h e a s t . The dykes are hornbleMe-lamprophyre. They range i n width from a few inches to about 40 f e e t . Come of the dykes are m i n e r a l i s e d , 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 are e n t i r e l y barren. I t seems that there i s no d i f f e r e n c e i n the dykes themselves, and that the m i n e r a l i z a t i o n of the l a r g e r dykes i s due to l o n g i t u  d i n a l f a u l t i n g and f i s s u r e s , which developed, because the l a r  ger dykes were l e s s competent than the small ones. I t has been siiown by the 4100 l e v e l that at depth the lamprophyre dyke may nhange i n t o a quartz-porphyry. This change does not a f f e c t the e n t i r e dyke. In case of the #2 Dyke the quartz-porphyry i s on the hanging v a i l s i de of the 139. dyke, while the normal basic materiel i s on the foot-wall side. This 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 material, and does not seem to a f f e c t the mi n e r a l i z a t i o n . The smaller dykes at the same h o r i  zon do not show t h i s feature. More information about this 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 of quartz-porphyry dyke and lamprophyre dyke should be watched f o r very closely as i t i s l i k e l y that the change w i l l be gradual. The dykes have been faulted both l o n g i t u d i n a l l y and transversely. In addition 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 oxidized and decomposed the dyke to a great depth, r e s u l t i n g i n bands of gauge. The lo n g i t u d i n a l movements appar ently preceded the mi n e r a l i z a t i o n , while the transverse were post mi 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 for mineralizing solutions to come upward, and l a t e r pro vided channels for water to percolate down - and cause secondary enrichment near the surface. The dykes are not uniform i n width, but p i t c h and s w e l l . In some cases off-shoots are given out at low angles to the main dyke. Granite horses are frequently inclosed with 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, not over 2 feet i n width, and i n no case heve been observed to be miner-140. a l i z e d . They are c u t t i n g the b a s i c dykes at a f a i r l y high angle, and are l a t e r than the lamprophyre dykes. Probably these dykes represent the a c i d end phase of the q u a r t z - d i o r i t e . ORE DEPOSITS. The o r e , with e x c e p t i o , of the Granite Y e i n , occurs i n v e i n s w i t h i n the dykes. In g e n e r a l the v e i n s are w e l l d e f i n e d p though they are bordered by some replacement of the dyke rock and i n some p l a c e s , of the g r a n i t e I t s e l f , In width they vary from a few inches up t o f i v e feet and i n a few cases are even wider, Although sometimes occuring i n the i n t e r i o r of the dykes, they show a preference f o r the w a l l s and f o r the margins o f s l a b - l i k e i n c l u s i o n s or horses of g r a n i t e . The c h i e f sulphides are a r s e n o p y r i t e , s p h a l e r i t e , g a lena, 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 . T e t r a h e d r i t e occurs 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 probably some other s i l v e r s u l p h i d e s and arsenides are pro bably secondary. The predominant gangue m i n e r a l i s q u a r t z , glassy- i n appearance. The vei n s are u s u a l l y t i g h t , but o c c a s i o n a l l y q uartz l i n e s vugs or shows comb s t r u c t u r e . The mine a l i z e t ion varies' from f i l l i n g of pure quertz and coarse grained s u l p h i d e s to replace/?©nt of the dyke rock by quartz c a r r y i n g f i n e g rained 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 of other s u l p h i d e s . Contrary to the i m p l i c a t i o n of the term ''mineralised dykes" the ore i s confined l a r g e l y to true veins w i t h i n the dykes and the a i l i c i f i e d dyke rock grades i n t o e n t i r e l y un-141. mineralized dyke material. 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 either free i n the gangue, or assoc iated with arsenopyrite. 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 lead r a t i o commonly i s 1 oz. per 15 Pb. Examination of several polished sections under micro scope , and core l a t i n g the sequences of mineralization indicates several periods of mineral! '.:a ti o n i n the following manner; 1) C r y s t a l l i n e quartz 3) Galena 3) Sphalerite 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) Pyrargyrite 11) Quartz {chaloedonic f i l l i n g fractures) IE) C a l c i t e . This sequence indicates several generations of quartz and might mean that three mineralizing periods were experienced. But this should not be regarded as d e f i n i t e and further 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 that the high grade ore body i n 4 5 0 0 l e v e l i s changed to arsenopyrite and p y r r h o t i t e c a r r y i n g very low v a l u e s . P r a c t i c a l l y the same c o n d i t i o n e x i s t s i n 4 1 and 42 tu n n e l s . The high grade ore shoot of 4A changes to Arsenopyrite i n 4 E . I t i s the r e f o r e p o s s i b l e that t h i s may be an i n d i c a t i o n of a g e n e r a l c o n d i t i o n . That i s , that high grade ore shoots are terminated by h e a v i l y m i n e r a l i z e d shoots of 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 t h i s i s c o r r e c t i t would be a d v i s a b l e , while c o n t i n u i n g the d r i f t s i n 4100 l e v e l to 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 shoots 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 high grade galena- s p h a l e r i t e lenses above. The G r a n i t e V e i n . The Granite V e i n presents an e n t i r e l y d i f f e r  ent type o f v e i n from the v e i n s found i n dykes. So f a r only one v e i n of t h i s kind i s known on the property. The v e i n f i l l s a shear or 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 . The gangue i s q u a r t z . The sulphides are v e i l c r y s t a l l i z e d , and are low i n i r o n . I t s occurrence close to the main |2 v e i n , d i p , and s t r i k e and presence of l a r g e w e l l formed c r y s t a l s of p y r i t e and galena at 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 of the quartz seems to c o n t r a d i c t t h i s view. A more d e f i n i t e answer could be obtained by a m i c r o s c o p i c a l examin a t i o n . I t seems that i t i s a true quartz v e i n , c a r r y i n g galena, 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 give v a l u a b l e i n f o r m a t i o n as regards 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 the MEsozoio Era - In 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 int r u d e d Into e a r l i e r sediments throughout the whole d i s t a n c e from the Yukon southward i n t o United S t a t e s . The g r a n i t e o f Yaughan Mountain was probably part o f t h i s great 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 cover o f hundreds i f not thousands o f f e e t . A t l i n R u f fner 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 that v i s i t e d the mine, that c r u s t a l adjustments 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 of 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 ith more b a s i c m a t e r i a l coming up from depth and forming the lanprophyre dykes. This idea i m p l i e s that 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 i n t r u  s i o n and came from the same source. However, more d e t a i l e d study of the problem suggests a d i f f e r e n t course o f events. ... Llndgreen i n n i s "Mineral Deposits" on Page 166 s t a t e s : " I n the l i t e r a t u r e many authors a t t r i b u t e f i s s u r e veins i n e f f u s i v e rocks to c o n t r a c t i o n , but u s u a l l y without s u f f i c i e n t reason. The t e n s i l e s t r e s s e s cannot produce long 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. "...the rocks which have formerly been f a r below the surfac e o f the e a r t h , but which have been exposed by er o s i o n are u s u a l l y t r a v e r s e d by more or 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 Llndgreen, L e i t h and other prominent g e o l o g i s t s a t t r i b u t e to r e g i o n a l 144. coinpressional s t r e s s e s . I t i s t h e r e f o r e c l e a r that the f i s s u r e s which were l a t e r f i l l e d w i t h dyke m a t e r i a l o r i g i n a t e d long 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 d a r i n g the next mountain b u i l d i n g p e r i o d , i . e . Laramide r e v o l u t i o n or l a t e r . A f t e r the dykes s o l i d i f i e d they themselves underwent f r a c t u r i n g . L o c a l l i z i n g o f the f r a c t u r e s and the dykes was due i n part to the c o n t r a c t i o n o f the dyke rock on c o o l i n g and i n part to the continued a p p l i c a t i o n o f the same forces which o r i g i n a l l y opened t h e f i a s u r e a . In other words, the dyke f i s s u r e continued t o be a l i n e of weakness and was reopened a f t e r c o o l i n g of the dykes. Into the f i s s u r e s i n the dykes so opened the ore 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 that m i n e r a l i z a t i o n was post J u r a s s i c , probably post Laramide, and occurred sometimes during T e r t i a r y , very l i k e l y during the Oligocene, which i s considered by J c h o f i e l d to be the next m i n e r a l i z i n g p e r i o d 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 probably the same magma which fu r n i s h e d the,, dyke rock but the d i f f e r e n t i a t i o n which produced the ore- bearing s o l u t i o n s occurred i n depth and not w i t h i n the dykes themselves. These s o l u t i o n s c a r r i e d s i l i c a , s ulphur, a r s e n i c and the metal3 i r o n , z i n c , l e a d , copper, s i l v e r and g o l d , besides c e r t a i n l y some f l u o r i n e and probably other m i n e r a l i z e r s which have escaped from the s o l u t i o n i n gaseous form. This # r 3. J. S e h o f i e l d , Ore Deposits of 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 metallic minerals i n the fi s s u r e s themselves but i n the dyke rock and to some extent the granite, replacing the wail rock by quartz and other ore minerals. Apparently the mineralizing solutions came up not once but about three times depositing new minerals and replac ing the older ones. There was some d i f f e r e n t i a t i o n i n the vein, so Galena and sphalerite came higher than the i r o n sulphides. There was a deep cover of rock overlying even the highest part of the present surface at the time the veins were formed, and t h i s has been removed by erosion which followed the elevation of the Coast Range In early Mesozoic and the subse quent re-elevation of early Tertiary 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 of ore deposits formed at intermediate temperature and pressure (rae so thermal deposits) whose depths of formation Lindgren describes as from 8000 to 12,000 feet. 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 possible for deposits of th i s sort to form somewhat nearer the surface i n some places. I t i s possible 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 hotter end of intermediate temperature. The r e g u l a r i t y of the veins, absence of breociation and c r u s t i f i o a t i o n and presence of pyrrhotite exclude the p o s s i b i l i t y that the veins are of low temperature o r i g i n . On the other hand, the absence of such minerals as garnet, araphibole, pyroxene, etc., coupled with the presence of te.inantite and the appearance of the quartz exclude a high temperature (hypothermal) o r i g i n . The coarse texture of the 146. sulphides, general absence of vugs ana r a r i t y of comb structure and occurrence of pyrrhotite point toward the warmer end of intermediate temperature. Further i t i s possible to say that the high temperature end was towards west, which explains greater amounts of pyrr h o t i t e and arsenopyrite, and less massive galena carrying lower values in s i l v e r . I t i s therefore reasonable to expect better grade s i l v e r - l e a d ore farther east, which w i l l also extend to a greater depth. This has been w e l l demonstrated both by the 4100 tunnel and the surface workings higher up on the mountain. The sign i f i c a n c e of the fact that tne deposit i s of an intermediate temperature type, I s , that me3othermal deposits are In general more persistent than those of low temperature. Mi n e r a l i z a t i o n of the same general type i n veins of t h i s nature l a *:nown i n many parts of the world to persist throughout a v e r t i c a l range of 1000 feet and i n some eases even 2000 feet or more and h o r i z o n t a l l y f or distances of many thou sands of f e e t , though any single vein does not necessarily per s i s t throughout the en t i r e range. Experience has shown that i n such ore copper values often increase i n depth, which has been demonstrated by our 4100 l e v e l , though the difference i n eleva t i o n necessary to produce any noticeable change i s r e l a t i v e l y l a r g e — o n the order of 1000 feet or more. On the other hand, primary deposits of bonanza s i l v e r Ore are formed at lower temperature, and i f found In a deposit of t h i s type would occur nearer the o r i g i n a l surface or farther out from the center of mineralization, any extremely r i c h ores found here w i l l probably be of secondary o r i g i n . 147. Secondary Barlohment. fhe high s i l v e r values so f a r found are i n ore that l i e s near the surface and l a a l l cases shows more or l e s s o x i  dation* fhe specimens from 4500 l e v e l open cuts and a d i t wnieh gave assays o f 500 oz. and over c o n s i s t e i t h e r o f earthy black o x i d i z e d m a t e r i a l or o f galena c a r r y i n g v i s i b l e ruby s i l v e r , f h e l a t t e r m i n e r a l i s a s t r a n g e r to primary ore o f the higher temperature mesothermal type and may best be explained by en richment. The earthy ore carrying l i t t l e l e a d may have I t s values In f i n e l y disseminated native s i l v e r , c h l o r i d e s or s i l v e r sulphides. The occurrence o f the best secondary ore i n the lowest exposures so f a r opened up may at f i r s t seem anomalous but may be understood when the topography i s considered. In the f i r s t p l a c e , deep f r a c t u r i n g which 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 . Secondly, the g l a c i a l p l a n i n g of tne early period may have removed secondary ores from the higher parts of the h i l l . Thirdly, erosion on the higher part of the h i l l may have been so fast as to have overtaken enrichment. I f enrichment under modern climatic conditions may be considered i t must a l s o be remembered that high on the h i l l the ground i s perpetually frozen. Sven in late summer and at d i s t a n c e s of 100 feet or more below the surface the open fractures are a l l f i l l e d with * ice, and abandoned tunnels soon become lined up w i t h ice crys t a l s . Thus f r o s t i s retarding i f not altogether preventing ground-water circulation in the upper parts of the h i l l while 148. a t lower e l e v a t i o n vadose c i r c u l a t i o n continuea. S l i g h t c l i m a  t i c changes from century to century would s h i r t the l i n e o f f r o z e n ground water up or down. S t i l l another c o n s i d e r a t i o n t h a t must not be overlooked i s that a l l the open cuts and underground workings so f a r d r i v e n on the upper slopes o f the h i l l have been where surface showings were best, hence where the e r o s i o n has been l e a s t deep, and consequently the areas 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 avoided. S e c o n d a r i l y enriched ores have so f a r shown such high values t h a t they r i c h l y repay a c t i v e search, p a r t i c u l a r l y as the depth to which they extend i s not known and may be such as to o f f e r very co n s i d e r a b l e tonnages. The determining f a c t o r s f o r secondary ores seem to be: 1} Presence o f galena f u r n i s h i n g s i l v e r values i n the primary ore. 2) Fracture zones along which e n r i c h i n g s o l u t i o n s may pass downward. 3) Presence o f Galena, 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 p r e c i p i t a n t . 4} P r o t e c t i o n from g l a c i a l or r a p i d surface e r o s i o n which has removed enriched ore. In p r ospecting f o r enriched ore I t would be w e l l to r a i s e on any g a l e n a - r i c h shoots encountered i n deeper workings i n the hope o f f i n d i n g enrichments near the s u r f a c e . U n t i l c o n d i t i o n s are bet t e r understood, i t would a l s o be a wise experiment to r a i s e sph a l e r i t e shoots, even though they may not show good s i l v e r v a l  ues i n the primary ore, 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 minerals and may be enriched near the surf a c e . L 149 • P O S S I B I L I T I E S . Humber 2 dyke has been traced 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 . #4 dyke has not been d e f i n i t e l y traced 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 probable t h a t i t continues as f a r as #2. Taking #2 dyke from e l e v a t i o n 4100 to the surface and comparing i t s t o t a l area, w i t h that part o f i t which has been opened up, i t i s apparent, t h a t only 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 to approximately 6$. I n t h i s 6;i o f the area o f the dyke s e v e r a l ore bodies have been dis 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 blocked out. I t i s the r e f o r e probable that other ore oodles e x i s t i n the unexplored p o r t i o n o f the dyke. I n a d d i t i o n to the p o r t i o n o f the dyke above 4100 l e v e l , the type of d e p o s i t makes i t p o s s i b l e f o r ore to extend f a r t h e r down f o r a co n s i d e r a b l e d i s t a n c e . In s e v e r a l places along the s u r f a c e , namely 2A, 2B, & 20 shoots o f high grade ore have been found, -..one o f these ore shoots has been tested f o r I t s extent downward; but the 4100 l e v e l g i v e s us evidence t h a t galena and s p h a l e r i t e are extend i n g f o r a t l e a s t 1000 fe e t below the 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 v e i n . And there are i n d i c a t i o n s that galena i s more massive i n t h i s v e i n . Between #2 and #4 veins l i e s a l a r g e area, whose topo graphy seems to 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 . The low saucer l i k e depression In the c e n t r e , and a' trough connecting i t with the #2 v e i n system might I n d i c a t e an area where er o s i o n has been 150. more rapid because of possible series of fa u l t s or f i s s u r e s . As shown elsewhere on the property such depressions usually indicate presence of dykes. I t i s therefore possible, that one or several dykes of the basic type, or maybe "Granite" type may occur i n th i s region. I t mast be remembered that t h i s i s only a conjecture, and that there are no positive indications of dykes on the sur face. But as i t i s planned to drive 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 greatly to the value of the mine. The ore shoots are i n general short, and the high grade lenses narrow. There are indications that they might follow i n eschelon, but so f a r no information i n regard to c o n t r o l l i n g factors of ore body locations i s avail a b l e . The distance between ore bodies, as shown on the surface i s about 2000 feet. SUMJAHY. 1) Veins are usually associated with basic dykes, but may also be i n quartz-diori te. 2} Chief gangue minerals are quartz and c a l e i te, i n some eases sulphides are disseminated i n dyke i t s e l f . 3} Veins prefer margins of the structures, and usually are on the footwall side of the dyke. In case of 4100, the best mineralized part of the vein i s on the contact of quartz- porphyry and lamprophyre. 4J Ore bodies are terminated by arsenopyrite and pyrrhotite. 151* 5) High values may he found near the surface o v e r l y i n g s t r o n g l e a s e s o f galena and s p h a l e r i t e , advisable to r a i s e on such l e n s e s . 6} S i l v e r accompanies galena. Common r a t i o i s 1 0 2 . ag per Vfo j?b. Gold i s e i t h e r f r e e i n the gangue or accompanies a r s e n o p y r i t e . 7) Galena and S p h a l e r i t e are primary 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 f e e t . 8) The ore was formed under c o n d i t i o n s o f intermediate tempera ture and pressure. 9} B e t t e r grade ore i s more l i k e l y to occur f a r t h e r e a s t , and go deeper there than a t 4300 l e v e l , because the higher temperature seems to have been west o f present workings. 10) Ore shoots are comparatively s h o r t . Borders of commercial ore can be best determined by a s s a y i n g . 11) Ore shoots are. spaced about 2000 f e e t , h o r i z o n t a l l y from each other, as at present i n d i c a t e d by surface -workings. 152. A t l i n D i s t r i c t . Copper Veins. "Copper vei n s occur on the southwestern eox*ner o f Copper I s l a n d i n a t l i n Lake. The rock formation c o n s i s t s o f r e d d i s h 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 c o n s i s t almost e n t i r e l y o f b a s a l t i c fragments, but grade i n t o rocks c o n t a i n i n g a predominance of sedimentary m a t e r i a l s . The reddish b a s a l t s range i n c o l o u r from brownish red to g r e e n i s h red, 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 . The 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 phenocrysts of o l i v i n e and augite 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 copper, a l l o f which are r e a d i l y v i s i b l e to the unaided eye. In places the groundmass becomes r e l a t i v e l y s m a l l i n amount, causing the rocks to have a decidedly g r a n u l a r appearance. Th© greenish 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 - green In 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 , c h i e f l y i n c o n t a i n i n g much l e s s I r o n , to which l a due the red c o l o u r  a t i o n . The Veins. A number o f veins from a f r a c t i o n of an inch to 6 Inches i n thickness occur 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 places con t a i n p a r t i c l e s and masses of n a t i v e copper, tne l a r g e s t o f which known to have been found, i s reported to have weighed about 40 pounds. A c e r t a i n amount of malacnite as w e l l as rare {D. D. Calrnes. 0. 3. C. Mem. 37. p. 114 - 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 occur as o x i d a t i o n products o f the n a t i v e copper." D. D . Cairnes concludes from h i s examination of t h e d e p o s i t s t h a t the copper was deposited In a n a t i v e s t a t e . In regard t o the o r i g i n o f copper he says: "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 with the i r o n which i s decidedly primary to the b a s a l t s , i t might be supposed that t h e copper had the same o r i g i n . However, the copper both i n th© veins and w a l l s i s qu i t e the same, and tha t In the veins i n a c a l c i t e gangue I s unquestionably secondary to t h e b a s a l t s . Some have supposed that the ve i n copper has been leached from the a d j o i n  i n g w a l l s where t h i s mineral I s thought t o be a primary c o n s t i  t u e n t . I f t h i s were so there would be a decreasing amount o f copper i n the w a l l s as the veins are approached. Instead, q u i t e the opposite appears to be the case, and the copper i s much more p l e n t i f u l In the b a s a l t s a d j o i n i n g veins and other f i s s u r e s . I t , t h e r e f o r e , seems evident that a l l the copper both i n the w a l l s and veins was deposited at the same period 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 , probably d e r i v i n g t h e i r m i n e r a l content from the s t i l l heated lower 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 the great amount of i r o n ore i n the 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 the copper to deposit i n the na t i v e form." The l a s t statement, i n regard to copper coming from the same b a s a l t i c magma does not seem very c o n v i n c i n g . I t seems much e a s i e r to a t t r i b u t e the formation of t h i s deposit to the Coast Range .Batholith, which i s j u s t a few miles west o f the occurrence. 154. The b a s a l t s themselves are o l d e r than the g r a n i t i c i n t r u s i o n , and I b e l i e v e t h a t there are no known mineral d e p o s i t s a s s o c i a t e d w i t h rocks o f t h i s age i n the d i s t r i c t . Antimony Veins. A deposit o f t h i s type I s known t o e x i s t about 10 miles north o f Golden Gate. The ore occurs i n form o f bedded v e i n s , i n the dark, f i n e l y t e x t u r e d shales o f Laberge s e r i e s . The main v e i n I s made of quartz and a t i b d i t e w i t h some 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 nothing e l s e i s known about the d e p o s i t . 155. A t l i n D i s t r i c t . Econ. Geol. Contact Metamorphic Qeposita. Contact-inetamorphic 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 only i n one l o c a l i t y which i s s i t  uated on Haboe Greek near the upper end o f Torres Channel, an arm o f A t l i n Lake. The 7 a l l e y o f the creek Is u n d e r l a i n p a r t l y by s c h i s t s , 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 lower l i t . Stevens group, the ag© o f which, C o c k f i e i d places t e n t a t i v e l y to "Pre-Carabrian." A d j o i n i n g these rocks on the "west are the Coast Range g r a n i t i c I n t r u s i v e s . The contact metamorphic ore d e p o s i t s are Included i n the Mt. Stevens rocks near t h e i r contact w i t h the g r a n i t i c i n t r u s i v e s . Ore d e p o s i t . The ore deposit i s a t one p o i n t approximately 150 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 mainly o f magnetite, 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 , m a l a c h i t e , c o b a l t bloom, and various s i l i c a t e s i n c l u d i n g considerable y e l l o w garnet, apparently g r o s s a l a r i t e , and some b i o t i t e . The rock that has been a l t e r e d and r e p l a c e d i n the f o r  mation o f the o r e - m a t e r i a l s appears to have been mainly, i f not e n t i r e l y , the Milestone which occurs i n bands o f various t u i c k - (Robertson, >/. F. Report on the M i n i s t e r o f Mines, 1904) (D. D. Cairnes, C. S. C. Mem. 37. p. 117.) 156. . noaa i n the l i t . Stevens s e r i e s , bat I n places the limestone has s u f f e r e d merely 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 best showing i s on the French c l a i m , on which a c r o s s - c u t tunnel 188 fe e t long has been d r i v e n , o:' whieh more than 130 f e e t i s i n the ore-body; t h i s assays from 1.65;* to 6;£ copper, and i t l a thought t h a t a con 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 deposit extends up to 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 contact which l a about 50 i n e l e v a t i o n above the v a l l e y . Other showings do not show the same h i g h grade ore, but t h i s i s not c o n c l u s i v e since only a few short outcrops are known. The r e s t o f the contact i s covered w i t h d r i f t . Genesis and Age o f Deposits. " I n studying the genesis o f these 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 noted. In the f i r s t p l a c e , the minerals c o n s t i t u t i n g the ore body or ore bodies are c h i e f l y magnetite, 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 , yellow garnet, and other complex s i l i  c a t e s . This combination o f Hematite and magnetite w i t h s u l  phides i s very c h a r a c t e r i s t i c o f contact metamorphic deposits and 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 minerals occur with yellow garnet 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 which i s d i a g n o s t i c of contact- metumorphisra. 157. F a r t h e r , these ore-minerals occur only near the i n t r u s  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 limestones i n t e r c a l a t e d i n the Mt. Stevens s e r i e s . f h e r e thus appears to be l i t t l e or no doubt, but what these ores owe t h e i r o r i g i n to the neighbouring g r a n o d i o r i t e s and that the m a t e r i a l s composing them sere derived from the g r a n o d i o r i t e magma, as the limestone and a d j o i n i n g s c h i s t o s e rooks do not c o n t a i n the necessary i r o n , copper, and sulphur f o r t h e i r p r o d u c t i o n . The contact 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 vapours, r i c h i n I r o n , copper and sulphur, which were de r i v e d from the g r a n i t i c i n t r u s i v e body. I f t h i s i s true the deposits were formed during the c o o l i n g p e r i o d of the g r a n i t i c b a t h o l i t h , which as explained under "general geology," i s thought to have occurred i n J u r a s s i c and probably l a t e J u r a s s i c time. 158. PART IV. B i b l i o g r a p h y 159. PART IV. B i b l i o g r a p h y . 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 23, 1913. Bateraan, A. M. G e o l o g i c a l Survey o f Canada. Summ. Rept. 1912. Buddington, A. F. 1) "Coast Range I n t r u s i v e s o f Southeastern A l a s k a . " J o u r . Geol. Y o l . 35. So. 3, 1927. 2) U. S. G. S. B u l l e t i n 800. Bostock, H» S. G. S. C. Summ. Rept. 1929. "Geology and Ore Deposits o f K i c k e l P l a t e Mountain, Hedley, B. C." Brock, R. G. 3* C. Summ. Rept. 1920. "Eutsuk Lake D i s t r i c t , 3. C." "Reoonaissance o f Ootaa, tfhitesail and Eutsuk Lakes. Brooks, A. H. 1} U. 3. G. S. P r o f , paper Ho. 45 "Geography and Geology o f Alaska." 2) U. 3. G. S. Annual r e p o r t . P a r t 2. 1900. "A Reoonaissance from Pyramid Harbour to Eagle C i t y , Alaska." 160. 0. 5. Gairnea. 1) G. 3 . 0. Suaa. Rept. 1920. "C o q u i h a l l u Area, B. 0." 2) G. 3. 0. Soma. Rept. 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 Yale and Similkameen Mining D i v i s i o n s . " 3} G. 3. G. Memoir 139. "C o q u i h a l l u Area, B. C " 4 } G. S. C. Soma. Kept. 1929. "The Serpentine B e l t o f C o q a i h a l l a Region, Yale D i s t r i c t , 3. C " Cai 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 tne Lewes and Iforden- s k i o l d R i v e r a Coal D i s t r . , Yukon t e r r i t o r y . " 2) G. 3. 0. Memoir 31. "rfheaton D i s t r i c t . " 3} G. 3. 0. Memoir 37. " P o r t i o n s o f A t l i n D i s t r i c t , B. C." 4 ) G. S. C Memoir 67. "The Yukon-Alaska I n t e r n a t i o n a l Boundary between Poroupine and Yukon R i v e r s . " 1914. 5} G. S. C. Suora. Rept. 1910. " P o r t i o n s o f A t l i n D i s t r i c t . " 161. C a i r n e s , D. D. (contd.) 6} 0. S. C. 3arma. Rept. 1916. " P o r t i o n s of Conrad and ./hitehorae Mining D i s t r i c t s . n 7} G. S. C. Summ. Rept. 1915. "Mayo Area; and Coroggie, Barker, T h i s t l e , and Kirkman Creeks,; and Wheaton D i s t r i c t Yukon T e r r i t o r y . " 8) G. S. C. 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 ores." Jour. Canadian Mining 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. Trans. Vol.XVIII (1915) Camsell, C h a r l e s . 1) G. 3. C. Mem. 26. "Geology and M i n e r a l Deposits o f Tulameen D i s t . B. C." 2) G. 3. C Mem. 2. "Geology and Ore Deposits of Hedley Mining D i v i s i o n . " 3) "The o r i g i n and H i s t o r y o f the Great Canyon o f the Fraaer R i v e r . " Trans. Royal Soc. Canada. V o l . 14, see. 4, 1920. C o c k f i e i d , . >/. 3* 1) G« 3. C» Summ* Rept. 1920. • " S i l v e r Lead Deposits o f the Keno H i l l Area, Mayo, Yukon." Z) G. S» C Surara. Rept. 1922. " E x p l o r a t i o n s i n Southern Yukon." 3) 0. 3. G. Summ. Rept. 1923. " S i l v e r Lead Deposits of Beaver R i v e r Area, Yukon." "Geology and Ore Deposits o f Keno H i l l , Mayo D i s t r i c t . ? 1 4) G . S. C. Summ. Rept. 1925. " E x p l o r a t i o n s between A t l i n and Telegraph Creek, B. C." " S i l v e r Lead Deposits o f A t l i n D i s t r i c t , 3. C." 5) G. S. C. Summ. Rept. 1926. " A i s k l h i k Lake D i s t r i c t . " 6} G. 3. C. Summ. Rept. 1927. "Dezadeash Lake -\rea, Yukon." 7) G. 3. C. Summ. Rept. 1929. "The Mining Industry o f Yukon." C o c k f i e i d , E. and. B e l l , A. H. G. 3. C. Memoir 150, 1926. " i/hitehorse D i s t r i c t , Yukon." Daly, R. A. " T h e nomenclature of 'A. , i . C o r d i l l e r a between the 47th and 53rd p a r a l l e l s o f l a t i t u d e . G e o g . J o u r n a l . June, 1906, p. 588. 163. loImage, f . 1} G.3.C 3oram. Rept. 1924, "Chiko Lake & V i c i n i t y . " • 2} " " 1925, " T a t l a - 3 e l l a Goola .reu." 3} " " " 1928, "Gun Creek Map .frea, B.C." 4} " " " 1922. Dawson, 0. M. 1) G.S.C. Rept. o f Progress. 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 Columbia." 2) G. S. C. 1887. "Report on e x p l o r a t i o n of Yukon D i s t r i c t . " 3) G. S. C. Annual Report. V o l * 7, 1894. "Suram. Report of i n v e s t i g a t i o n s i n southern 3. C." 4) G. 3. C. V o l . X I I p. B. 1899. "Report on A t l i n f i n i n g D i s t r i c t . " 5) G. 3. C. Sumra. Rept., 1896. V o l . V I I . 6) " G e o l o g i c a l Record of Rocky Lmt. r e g i o n . " B u l l . Geol. lioc. o f America. 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 Region i n Canada." Trans. Royal S o c i e t y , fanuda. Vol. 8, Sec. 4, 1690. 8) G. S. Q, Annual Report. 1894. Vol.. V I I . P. 10B. Garwood, J5. J . "Features o f a l p i n e Scenery due to G l a c i a l p r o t e c t i o n . " Geog. J o u r n a l . Sept. 1910. p. 317. 164. G w i l l i m , J * C . 1} Rept. to the 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., - 751. "Report on A t l i n Mining D i s t r i c t . " 3) G.S.C. Annual Rept. V o l . A l l I 1900 p.52A - 62A. 4 } "Notes on A t l i n Gold F i e l d s . " J o ur. 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 " Jour. Can. Mln. I n s t . 1902. p. 21 - 33. Hanson, G. 1) G.S.C. Suram. Rept. 1922. P.A. "Reconnaissance 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 Stewart, 3. C . " 3) G.S.C. Summ. Rept. 1924. "Pr i n c e Rupert to Burns Lake." 4 ) G.S.C. Summ. Rept. 1925. "Recouaissanoe i n Zyraoetz R i v e r .jrea." 5} G.S.C. Suram. Rept. 1928. "Mineral Deposits o f A l i a e Arm D i s t r i c t . " Hanson, G. and Phemister, T. C . G.S.C. Summ. Rept. 1928. "Topley Map Area, B* C . 165. H u r s t , M. S. C. S. G. Summ. Rept. 1924. "Tungsten Deposits near Hazelton, B. C." Jones, R. H. B. G. S. C. Summ. Rept. 1925. "Geology and Ore Deposits o f Hudson Bay Mountain, 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 area, 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 . Area, 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 . area." 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 on Isk u t River Area." Lang, A . H. G. S. C. Sum. Rept. 1929. "Owen Lake Mining Camp." Leach, W. 1) G.S.C. Summ. Rept. 1909. "Skeena R i v . D i s t r . " 2) " " " 1910. 11 " " 166 • Li n d g r e n , W» "M i n e r a l Deposits." Mackenzie, J . D» 1) G. 3. C Surara. Rept. 1920. "The l i m o n l t e deposits o f Taseko V a l l e y " "A Reoonaissance between Taseko Lake and Fraser R i v e r . " " C h i l c o Lake." Mandy, J. D. 1) M i n i s t e r o f Mines Reports 1929, 1930. " A t l i n S e c t i o n . " . 2) Min. o f Mines Rept. 1929. p. 133 C. "Taku R i v e r Area." 3) K i n . o f l i i n e s Rept. B u l l . 1, 1930. "Taku R i v e r D i s t r i c t . " Marshall,. 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 Area, B. G." 2) G. 3. C. Summ. Rept. 1925. "Eutsuk Lake area, 3. C." 3) G. S. C. Summ. Rept. 1926. "Lakelse Lake Map Area, Coast D l s t r . 8. C. 167. McConnell, R. G. 1) G.S.C. arm. Rept. V o l . XI7 part B. "Report on Klondike Gold F i e l d s . " 2) G.S.C. nan. Rept. V o l . IV, 1888 - 1889. 3) " Summary Report 1904. 4} " "V/hitehorse Copper B e l t . " 1909. 5) " Summary Report 1912. "G e o l o g i c a l s e c t i o n along the Grand Trunk P a c i f i c R. R. from P r i n c e Rupert to Alderraere." 6} G. S. C Memoir 32, 1913. "P o r t i o n s o f P o r t l a n d Canal and Skeena Mining 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 Deposits o f the Bridge R i v e r Map Area, 3. C." 0 * H e i l l , J . J . G. S. C. Liemoir 110, 1917. " P r e l i m i n a r y Rept. on the Economic Geology o f the Hazelton D i s t r i c t . V. J . O k u l i t c h . "Geology o f the A t l i n Ruffner Mine" r e p o r t to the manager o f the f l i u e , 1931. 168. Reineeke Leopold. G. S. C. Memoir 118. "Mineral Deposits between L i l l o o e t and P r i n c e George, B. 0." Robertson, R. P. Annual Report. M i n i s t e r of Mines 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 Mining 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 Trans, o f the Royal Soc. Canada V o l . X V I I , l i i s e r . 1923, p. 79. 3} " F i s s u r e systems of B r i t i s h Columbia" Canad. I n s t . Min. & Met. J u l y , 1925. • 4) "The B r i t a n n i a Mines, B. C." Economic Geology, V o l . 21, ho. 3, 1926. 5) "Ore Deposits of B r i t i s h Columbia" Chap. IV. Memoir 132. G. 0. C. Schofield, S. J . and Hanson, G. G.S.C. Memoir 132. "Geology and Ore Deposits of Salmon River Area." 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." Spencer, A . G. " P a c i f i c Mountain System In B r i t i s h Ooiumb and a l a s k a . " B u l l . Geol. Soc. of ..aaerica, Y o l . 14. Vestgate Lewis, G. i j . a. (>. S. d u l l . 722 C. P. 117. "Ore deposits o f trie Salmon I i i ver D i s t r i c t Young, R o s a l i n d , ./. "Mining i n A t l i n , B. G." .Tourn. Can. l i i n . I n s t . 1909. 140° 139C 138c 137c 136c 135° 134' 133' 132' 131° 130c 129' 128c 127c 126° 125° 124° 123e 58 56 55 54 53 52 50 49 \Gate .yanov N MMWb^XMKm& D IP JLAB3TO H O N O U R A B L E T. D, P A T T U L L O , M I N I S T E R 1,1 Scale, 50 miles to 1 inch 100 160 7.IKI 48° L E G E N D L a n d D i s t r i c t s _ . R a i l w a y s M i n i n g R e c o r d e r O f f i c e s O ATLIN S u b - R e c o r d e r O f f i c e s © Moyio L ^r? P»po Soot ylJQ j»*A \ \ \ 122c [7 121' 120' 119' 116' 115' 114° US' 112c 111* r JS/elsoi i FORTI PNELSO E \ T iFt.Grahaine QtrtnanB 'Takla Landing Beatt,. E N T \ TH EC UNI VER 5 / T Y or BlR/T/SEf COLL/MB/A G£O LOG/C/) Z M/* P THE CO/4ST R//NGE BATHOL/TH. /93JI . 59 58° 57 56 Cttn im 4 f K \ a o i i a l tfobcrlv V -I M* s T ^ ^ T 0 0 tctMa't {Grande •"Prairie, Salmon V 4? * Foreman" *Dcwey * un i A A Ii B 53 -^ f Quetmet 5? SoJa Orcwi Alexin Crook/ jUexand Harpers! Wil^J Tete Jaune 11':,;, W11I0B0 d V l Clem'ma; * \ T\ 0 INVRT 'rBonouu H0 Campl-Spll Rival T K | A v Buttle; LcfKe 136° 135° 134° 133c 132e 131° 130° 129° Longitude 128° 0^  ,0 Taseho\ T . A l t o " Exeter C j v p o « OJ-eek Lake green ljafie 52 knye". I11500 _ I xDeer R., e L aylm'Vo \ V Srt^" " Powel Rivert ,v Alia , Jervi8\ Lake LPavirfS-li feiacfcPool mOti* ADAMS) 51 ttita Lai B RVDOUA T M I SguamiBliji/ ^» * N cou V E^^^^L^* XS^ L t h ^ Y. \A»P0U 0r07e 1 (LAKE tgeni* 50 X A 4 ^ /^  1 ARtty \hT\ 127° West 126° SlaJne jSope••50i'.(\pperelMt. ^ O I ^ Q OlWer <^T&mVWoa ObUlilw'H<J f f r ^ i k o R1A 125° from 124° •>i Mt.Baker «f ,ellM|ha4 10,827 A . / W6/ T 1M ^ " f l b ™ r t s 49 J W K J A ! T l d W o r e i U e •48 121° 119' 118' 117* 116c 115° MAP N ° |CX 

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