IMAGE EVALUATION 
 TEST TARGET (MT-3) 
 
 1.0 
 
 I.I 
 
 1.25 
 
 ^m iiM 
 
 >a m ||||Z2 
 12.0 
 
 U 111.6 
 
 Photographic 
 
 Sciences 
 Corporation 
 
 33 WEST MAIN STREET 
 
 WEBSTER, N.Y. 14580 
 
 (716) 872-4503 
 
 \ 
 
 iV 
 
 L1? 
 
 :\ 
 
 \ 
 
 % 
 
 .V 
 
 ^> 
 
 
 # 
 
 
 o^ 
 
 %' 
 
 ^ 
 
 W 
 
 m 
 
,*, 
 
 L<S> 
 
 
 ^ ^ 
 
 W 
 
 CIHM/ICMH 
 
 Microfiche 
 
 Series. 
 
 CIHM/ICMH 
 Collection de 
 microfiches. 
 
 Canadian Institute for Historical Microreproductions / Institut Canadian de microreproductions historiques 
 
Technical and Bibliographic Not8»/Notes techniques et bibliographiques 
 
 The Institute has attempted to obtain the best 
 original copy available for filming. Features of this 
 copy which may be bibiiographically unique, 
 which may alter any of the images in the 
 reproduction, or which may significantly change 
 the usual method of filming, are checked below. 
 
 L'Institut a microfilm^ le meilleur exemplaire 
 qu'ii lui a 6t6 possible de se procurer. Les details 
 de cet exemplaire qui sont peut-Atre uniques du 
 point de vue bibiiographique, qui peuvent modifier 
 une image reproduite, ou qui peuvent exiger une 
 modification dans la methods normaie de fiimage 
 sont indiquAs ci-dessous. 
 
 Coloured covers/ 
 Couverture de couieur 
 
 
 Coloured pages/ 
 Pages de couieur 
 
 Covers damaged/ 
 Couverture endommagte 
 
 
 Pages damaged/ 
 Pages endommag6es 
 
 Covers restored and/or laminated/ 
 — 1 Couverture restaurte et/ou peiliculAe 
 
 
 Pages restored and/or laminated/ 
 Pages restaur6es et/ou peiliculAes 
 
 Cover title missing/ 
 
 Le titre de couverture manque 
 
 7 
 
 Pages discoloured, stained or foxed/ 
 Pages dicolor^es. tacheties ou piqu6es 
 
 Coloured maps/ 
 — 1 Cartes g6ographiques en couieur 
 
 
 Pages detached/ 
 Pages d6tach6e8 
 
 Coloured ink (i.e. other than blue or black)/ 
 — 1 Encre de couieur (i.e. autre que bieue ou noire) 
 
 
 Showthrough/ 
 Transparence 
 
 Coloured plates nnd/or illustrations/ 
 — 1 Planches et/ou illustrations en couieur 
 
 
 Quality of print varies/ 
 Quality in6gale de I'impression 
 
 Bound with other material/ 
 — 1 Relii avec d'autres documents 
 
 
 includes supplementary material/ 
 Comprend du materiel suppl^mentaire 
 
 D 
 
 D 
 
 D 
 
 c 
 
 b 
 
 tl 
 
 s 
 
 
 
 fi 
 
 s 
 o 
 
 Tight binding may cause shadows or distortion 
 along interior margin/ 
 
 La reliure serrie peut causer de i'ombre ou de la 
 distortion le long de la marge intArieure 
 
 Blank leaves added during restoration may 
 appear within the text. Whenever possible, these 
 have been omitted from filming/ 
 II se peut que certaines pages blanches ajout6es 
 lors d'une restauration apparaissent dans le texte. 
 mais. lorsque cela ttait possible, ces pages n'ont 
 pas At A filmies. 
 
 Additional comments:/ 
 Commentaires supplAmentaires; 
 
 I I Only edition available/ 
 
 D 
 
 Seule 6dition disponibie 
 
 Pages wholly or partially obscured by errata 
 slips, tissues, etc., have been refilmed to 
 ensure the best possible image/ 
 Les pages totalemont ou partiellement 
 obscurcies par un feuiiiet d'srrata, une pelure, 
 etc.. ont 6t* filmAes h nouveau de fagon A 
 obtenir la meilleure image possible. 
 
 T 
 
 SI 
 
 T 
 
 IV 
 
 d 
 
 ei 
 b 
 ri 
 
 IT 
 
 This item is filmed at the reduction ratio checked below/ 
 
 Ce document est film* au taux de reduction indiqu* ci-dessous. 
 
 10X 14X 18X 22X 
 
 26X 
 
 30X 
 
 y 
 
 12X 
 
 16X 
 
 20X 
 
 MX 
 
 28X 
 
 32X 
 
The copy filmsd here hat been reproduced thanks 
 to the generosity of: 
 
 Library Division 
 
 Provincial Archives of British Colun.bia 
 
 The images appearing here are the best quality 
 possible considering the condition and legibility 
 of the original copy and in keeping with the 
 filming contract specifications. 
 
 Original copies in printed paper covers are filmed 
 beginning with the front cover and ending on 
 the last page with a printed or illustrated impres- 
 sion, or the back cover when appropriate. All 
 other original copies are filmed beginning on the 
 first page with a printed or illustrated impres- 
 sion, and ending on the last page with a printed 
 or illustrated impression. 
 
 The last recorded frame on each microfiche 
 shall contain the symbol — ^- (meaning "CON- 
 TINUED"), or the symbol V (meaning "END"), 
 whichever applies. 
 
 Maps, plates, charts, etc., may be filmed at 
 different reduction ratios. Those too large to be 
 entirely included in one exposure are filmed 
 beginning in the upper left hand corner, left to 
 right and top to bottom, as many frames as 
 required. The following diagrams illustrate the 
 method: 
 
 L'exemplaire film* fut reproduit grAce A la 
 gtnArositA de: 
 
 Library Division 
 
 Provincial Archives of British Columbia 
 
 Les images suivantes ont At6 reproduces avec le 
 plus grand soin. compte tenu de la condition et 
 de la nettetA de l'exemplaire film*, et en 
 conformity avec les conditions du contrat de 
 filmage. 
 
 Les exemplaires originaux dont la couverture en 
 papier est imprimAe sont filmAs en commenpant 
 par le premier plat et en terminant soit par la 
 derniire page qui comporte une empreinte 
 d'impression ou d'illustration, soit par le second 
 plat, salon le cas. Tous los autres exemplaires 
 originaux sont filmAs en commen^ant par la 
 premiere page qui comporte une empreinte 
 d'impression ou d'illustration et en terminant par 
 la derniAre page qui comporte une telle 
 empreinte. 
 
 Un des symboles suivants apparaitra sur la 
 dernidre image de cheque microfiche, selon le 
 cas: le symbole -^> signifie "A SUIVRE", le 
 symbole V signifie "FIN". 
 
 Les cartes, planches, tableaux, etc., peuvent dtre 
 film^s A des taux de rMuction diff^rents. 
 Lorsque le document est trop grand pour Atre 
 reproduit en un seul clichi. il est film* A partir 
 de Tangle supArieur gauche, de gauche d droite, 
 et de haut en bas, en prenant le nombre 
 d'imagos n6cessaire. Les diagrammes suivants 
 illustrent la m^thode. 
 
 1 
 
 6 
 
■.t^- 
 
 /^-' 
 
 c'^7 
 
 BULLETIN OF THE QEOLOQICAL SOCIETY OF AMERICA 
 
 Vol. 2, pp. 165-176 
 
 NOTE ON THE GEOLOGICAL STRUCTURE OF THE 
 SELKIRK RANGE 
 
 BY 
 
 GEOIUJE M. DAWSON 
 
 ASSISTANT DIKKCTOK OF TIIK QKOI.OOICAL 8URVBV OF CANADA 
 
 KOCH ESTER 
 
 I'UIJLISHED BY THE SOCIETY 
 
 Fbbkuary, 1891 
 
 /^S^ 
 
 »f ».v 
 
 ^u^. 
 
 -mimm^^*^- 
 
^WfS^pRfS 
 
 y I tJ"-(76,,'t3^,».<»<-«*'- 
 
 ^m§^wmmsm' 
 
 ft ■:i*im:'>m^^P' * 
 
 *\ 
 
 r- 
 
 
 -/ 
 
 I 
 
 
vam^m- 
 
 WiLPI!!ii«n'iP 
 
 BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 
 Vol. 2, pp. 165-176 February 12, i89i 
 
 J' 
 
 I 
 
 NOTE ON THE GEOLOGICAL STRUCTURE OF THE 
 SELKIRK RANGE. 
 
 EY GEOKOE M. DAW.SON, ArtSlJSTANT DIltlXTOK OF THK GEOf.OGIC.Vr, 
 .St;UVLY OF CAXADA. 
 
 {/{rail he/ore the Sui-icti/ December 29, ISOO.) 
 
 CONTENTS. 
 
 Page. 
 
 Introduftion 10.5 
 
 Genonil Feutiiros of the Cordiliorii ]()5 
 
 Surveys in the Interior PlaU'iui IJeijioii 106 
 
 Gooloijiciil Features of the Interior Pliiteau 107 
 
 Stratigraphy lo7 
 
 The General Section . 107 
 
 The Shiiswap .Series 170 
 
 The Nisconlith Series 170 
 
 The Selkirk Series 171 
 
 General lielutinns of the Cambrian. .. . 172 
 
 Newer liocks ... 174 
 
 Structure .... 174 
 
 Thickness ... 175 
 
 Discussion 170 
 
 
 Introductiox. 
 
 General Features of the Cordillera. — Tiie Cordillera, or Rocky Mountain 
 region of the Pacific coast, for a length measured by seven degrees of lati- 
 tude in the southern part of tlie province of British Columbia, is narrower 
 than elsewhere, having in this part of its course a widtli not much exceeding 
 400 miles. T!ie principal geographical features of this southern portion of 
 the Cordillera in British Columbia are now pretty well known, and the 
 general geological outlines have also been drawn in, so far as this can be 
 done from reconnoissance work. The districts which have been more closely 
 studied are few and limited in size. 
 
 Enough is known to show that this part of the Cordillera offers a geolog- 
 ical problem of great complexity, such as to require for its solution, even 
 
 XXV— Hui-L. Gbou. Soc. Am., Vol.. 2, 1890. . (165) 
 

 icr. 
 
 <;. M. D.wvsdN-— sTurcTrui; or tiik sKr.KinK iianok. 
 
 uiKlor the most fiivorable firciinistiuiccs), loiij,' iind careful msenrcli. In luldi- 
 tioii to till' (litticiiltiivs (if stniclun' to l)e oxpt'ctcil in any <rrcat mountain 
 system, spci'ial diHicultioM are found in tli« dej,'ree to wliioli rcj^ional mctiimor- 
 pliism has hecn caniod, in the uccninencc of great volumes of contemiiora- 
 neous volcanic material at various stashes, and (partly no douht as a conse- 
 •lucncc of the last) in the extreme paucity of fossil renuiins. Still further, 
 the circumstance that the region as a whole must he descril)ed as more or 
 less densely wooded, contrasts it very unfavoral)ly, from a geologist's point of 
 view, with the southern ami open parts of tlie t'ordiilera, where he who runs 
 may reatl numy of the main structural facts. 
 
 Up to the present time the horizons which have in British (Johunhia heen 
 actually fixed hy paleontological evidence may be summarized as follows: 
 
 1. Tertiary i;^prol)abiy Miocene). 
 
 2. Cretac<jous (various stages, probably extending from the Laramie as 
 far down as the Neocomian). 
 
 !!. Alpine Trias. 
 
 4. Carboniferous. 
 
 o. Silurian {Huh/sllex beds). 
 
 0. Cambro-Silurian (Trenton-Utica and perhaps somewhat lower). 
 
 7. Middle Cambrian. 
 
 8. Lower Cambrian {Okiiellns beds). 
 
 Of these horizons, all i)ut the Miocene have been recognized in the Rocky 
 Mountains [iroixT, or eastern range of the Cordillera. On the coast n(. fos- 
 sils definitely older than the Carboniferous have yet been detected. In the 
 interior plateau, fossils referabh; to the Miocene, lower Cretaceous, Alpine 
 Trias and (Jarboniferous have been rather sparingly found, while in the 
 mountain region of the (iold .system, including the Selkirk, Purcell, Colum- 
 bia and other ranges, we are as yet almost entirely without paleontological 
 evidence. 
 
 tSiirvei/s in the Interior Plntenn lieglnn. — The writer has been engaged for 
 some time in a detailed examination of an, area of about (5,400 square miles in 
 the interior plateau region, the nuiterials for a geological map of which have 
 now been obtained and are in course of elaboration. In connection with 
 this work, and more particularly to assist in explaining the complexities of 
 the older rocks of this area, it became desirable to ascertain, so far as pos- 
 sible, the relations of these rocks to those of the Rocky ^lountains proper, 
 across which one line of .section has already been carefully worked out by 
 Mr. H. (i. McCoiinell. 
 
 With this object in view a preliminary examination was nnide last autumn 
 across the intervening Selkirk range, on the line of the C'anadian Pacific 
 railway. This examination was lu'ce.ssarily confined to the vicinity of the 
 railway and still reipiires to be supplemented by much detail, to be obtained 
 
THE INTKUIOIt I'l.ATKAf ItlCfilON'. 
 
 167 
 
 only by mountain clitnl)ing, and by the study of a belt of some width on both 
 fides of tlie line. A.s, however, we have heretofore been almost without in- 
 fornnition on the geolof,'ical stnieture of the Helkirks, it is believed tlnvt the 
 observations made may not bewitiiout interest, even thonj,'h j^iven subject to 
 future correction in detail. This ran<re, where it has been rendered easily 
 accessible by the construction of the railway, has already become noted for 
 its .nagniticent Alpine scenery, wiiile some of its [xjaks and glaciers have 
 become tlie subjects of serious ex[)l()ration by well-known Alpine climbers 
 from England and Switzerland.* 
 
 GeoliKjlcal Features of tlie Interior Plateau. — In that part of IJritish Colum- 
 bia wiiich has been called tlie interior plateau the oldest stratified rocks are 
 gnei.5ses and micashists, which from their lithological character are assumed 
 to represent the Archean. The relations of these to the overlying Paleozoic 
 strata are best known on the ea.stern bm-der of the plateau region, Avhere 
 they are freijuently and well shown. Witii these crystalline schists occur 
 certain old granitoid rocks, which may represent either portions of the schists 
 in which the bedded structure has been ol)literated or very ancient intru- 
 sions that, together with the enclosing crystalline schists, have sub.seipiently 
 been affL'cted by heat, press ire and otiier agencies. Besides these there is in 
 the same region at least one later series of distinctly intrusive granites, which 
 is probably newer in date than most of the Paleozoic rocks. In the Coast 
 range, on the western side of the interior plateau, a similar "complex" of 
 crystalline schists and granites occurs, of whic!) part at least may be of the 
 same age with that just alluded to, thougli in this ctuse some of the intrusive 
 granites are known to be post-Triussie in date and others are later even than 
 the Cretaceous. 
 
 STHATIGRAPnY. 
 
 The General Section. — The section given in the first column of the annexed 
 table represents the rocks met with near the eastern border of the interior 
 
 < SiU'li Kf'>>'>Ki<'nl inilii.'iilioiis for tlu' SelkirUs «>< Imve ln'oii imbl!.'<lie(l may V)0 foiitid In the fol- 
 lowitif^ vvorky : 
 
 Iti'piiit on lli(> f;eolo){y of the Coiinlry nenr tho K.rlyniiilli Parallel of North Liitituile, by H. 
 Baiieriimn. This !•< tht- r"»iilt of ol.scrvmi >ii!< minln in IS'iii-'ill, in I'onnoclion wllh the expeiliiion 
 engaKPil In lixin;? Iho Honlhi'rii boiimlary of Hrilish t'oliimbia In those years, but was first publisliecl 
 In the Hcporl of Progress of the (ieolo^ieal Snrvey offanada for lghi-'S4. 
 
 Siiinniaiy Koport of the Uperations of tile (ieolonieal Survey for the year 18.S7, by Dr. A. R. C. 
 Selwyn. 'i'his ooniains a brief ncite on the eharaeter of the rocks riear Illeeillevvaet. 
 
 Kxplorations in the (ilneier Uenions of the Selkirk Range, Hritish ("oliimbia, by Rev. W. Spots- 
 w.iod Green; Proceerlinxii of the Hoyal (ieographieal Sonielv, vol. XI, 188'J. Mr. lireen here gives 
 a short geolngieal note (p. \(i7) anil refers to the diterniination by Professor T. (J. Bonney of some 
 of the roeUs hronght ba'-l;. 
 
 Notes on llie (ieography and Geology of the Hig Mend of the rolumbia, bv Professor A. P. Cole- 
 man ; Tians, K"yal Soe. fan., vol. Vll.seet. IV.ISW. In this paper the general geologieal chamcter 
 of disirlels vi>iled by the anthor are deseribed and the results of a petrologionl examination of a 
 nnmber of roeks are given. 
 
 Hrief mention has also been made by the writer of the rocks of the '^elklrks and neighboring 
 ranges in l>eserjptlve >'keteii of the I'liysieal <»ef)gra()hy and Geology of the Dominion of Canada, 
 IStil : .Mineral Wealth of Hrillsh I'olnmbia (Annnal Itepofi Geol. Snrv. I'an . new series, vol. Ill): and 
 elsewhere, A somewhat more detailed aeeonnt has been given by him of the geology of a part of 
 the western border of the Selkirks, resnlting frr»rn a r-eoonnolssanno made in iSSii and published 
 in IS'.ii) In his Report on a Portion of tho West Koolanie District (Annual Report Geol. Surv. Can., 
 new series, vol. IV). 
 
 19400^ 
 
•^nr 
 
 t 
 
 »5 
 
 O. M. DAWSON' — STUUCTUUE OF THR HKI.KIKK ItA.N'di:. 
 
 aSV NVIH.TllS-Oll'IKVf) 
 
 •xvninwvf) 
 
 •NVMH3«V 
 
 n mm 
 
 « a 
 
 52 
 
 
 S . 
 
 22 
 
 CO**' 
 
 
 'i5 
 
 ti: 2- 
 
 13 
 
 B 
 
 
 -3 
 
 s ^-S 
 
 
 
 t^ 
 
 O" - 
 
 3 
 
 -^ 
 
 1 1 
 
 a 
 
 U, 
 
 TI ?l 
 
 c 
 
 
 j;. 1 •> ■- ^ 
 
 13 
 
 
 ^ '"',— " 
 
 < 
 
 
 
 •O 
 
 
 j-. X = •■« 
 
 c 
 
 
 £ - ~ . !^ 
 
 
 
 
 s 
 
 
 
 S 
 
 
 = = c if, = 
 
 e 
 o 
 
 
 
 
 
 e 
 
 
 O -^ 
 
 o 
 
 
 
 
 
 Ci •■? 
 
 1 
 
 
 
 " 
 
 
 
 «■! - 1 
 
 ~-3 '" 1 
 
 t. "^ 
 
 i) 
 
 fc- _— - — 
 
 'O "E « "~ 
 
 c V =: ^ 
 
 ? "^ "k -T 
 
 O 
 ulnouG Miii 
 
 o = 
 
 1- 
 
 _C 3 
 
 'tr-^ - "^ = 
 
 
 * = - i = ' 
 
 tr B t^ 13 .i I 
 
 ***• m C" ^ ^ ' 
 
 ** J3 — -~ •-> 
 
 * r ■= c; - 
 
 •A s y. - .— "^ 
 
 
 •ttuas ujiiiy nog > 
 
 ■:! £ i 5 
 
 • S - 5 
 
 •5 -| J2 
 
 ^ -3 ^ -3 « 
 - 5 ? i " 
 
 'S9IJ9S' Y ''-y/Jy 
 
 s-»l.(./s' 
 
 -3 
 c 
 
 91 
 
 -a 3 
 
 •K3I.<»» 
 
 ifii.iimn/f^' 
 
 <U 0)'^, f 
 
 -3 ■■, = 
 
 
 s ;° 
 
 schisto 
 i son 
 
 o 
 
 W 1 
 
 •V , 
 
 
 C 1 
 
 '- * ! 
 
 til 1 
 
 
 a" 1 
 
 
 
 J S 5 
 
 ■=s 
 
 
 
 
 
 — ^ .— 
 
 .1 a 
 
 — 
 
 s 
 
 ri 
 
 -■ 
 
 •K./I.O* 
 
 ■SUMS 
 
 yf!]Hom\r 
 
 dvaisntff^ 
 
 m- 
 
COIfUKr.ATIVKS or TIIK SIcr,KII!K roHMATtONrt. 
 
 169 
 
 i:iJlV 
 
 '/.v 
 
 plateau rofiion and is based on ()])scrvati()ns inado on Koofanio lake in the 
 western flanks of the Sclkirks, snpplenicnted by a seetion found on and near 
 Adams and tlie Siiuswap lakes, altout 1 ")() miles to the northwest of the first- 
 mentioned locality. The lowest rocks in this column are those referred to 
 the Arciiean, the tliickiu-ss stated hein^ merely that known to occur on 
 Kootanie lake. The rocks included in the Adams I^ake series, consisting of 
 fi;ray and green schists, and forminj; so large a part of the <'ntire thickness, 
 have l»een merely referred in a general way to the Paleozoic. In their 
 typieal locality they appear to be distinctly traceable on their line of strike 
 into contemporaneous diabase and diorite rocks, which are often agglom- 
 erates, and pass into volcanic ash rocks, where their constituents become 
 finer. The peculiar lithological character (which, taken by itself, might be 
 supposed to indicate that the rocks siiould be classed as upper parts of the 
 Archean) of these Adams T^akf «chists is thus believed to depend chiefly on 
 the dynamic metamorphism resulting from extreme pressure which has 
 affected the volcanic components of the Paleozoic, where these have been 
 includeil in the strict flexures of the mountain region of the Gold system. 
 No direct paleontological (!vidence is, however, forthcoming with respect to 
 the age of the rocks of this first column of the table. 
 
 The third column in the table represents Mr. McC'onnell's published sec- 
 tion in the Rocky Mountains proper, in which certain horizons, ranging up- 
 ward from the lower Cambrian, ai*e definitely fixed by fossils. It was found, 
 in working out the section in this part of the Tvocky Mountains, that a consid- 
 erable difl'erence exists between the section of the eastern as compared with 
 that of the western part of the range, the pre«ent width of which (whatever 
 that originally occupied by the rocks com[)o8ing it may have been) is about 
 sixty miles only. The particular feature of this change which is interesting 
 in the present connection is that observed in the Castle Mountain (Cambrian 
 and Canibro-Siliirian) group, which, although it is on the east essentially a 
 limestone formation, is found on the west to consist in large part of greenish 
 calc-schists and greenish and redilish shales and slates.'*^ No granitic rocks 
 or true crystalline schists are seen in any part of this section. 
 
 The .section rejjresented by the middle column in the table is that now 
 obtained for the Selkirks. It occupies, geograj. >iically, as it does in the table, 
 a position intermediate between that of the eastern border of the interior 
 plateau and that of the Ilocky Mountains. In this, as in the section given 
 in the first column, no horizons have yet been fixed paleontologically, and the 
 position given to the rocks therefore depends ]>rincipally on the comparison 
 of the section with that known in the Rocky Mountains proper. It is prob- 
 able, from the composition and condition of the rocks, that they may yet be 
 found to hold fossils: but in the meantime it is believed that the lithological 
 
 * Annual Report Geol, Surv. Can., 1886, pp. 24i), 25d. 
 
170 
 
 (i. M. DAWSON — sritlCTIKI': til' TIIK SKI.KIKK ll.VNdi;. 
 
 
 ri'H('iiil)lan('<' ol' the ronnutidii.s to tiiusc met willi in i\n' liucky MiniiitainH in 
 ill itsult'.xufiicii'iit to t'lmiile some imporliiiit ;;('iu'nil ("oiicluxioin to i)e iirrived 
 Bt respcclinj,' tlie rovkn of tiie Selitirk niiijje, wliiie tlie uimlo^iy of tlio rockH 
 of the Scikirks to tlioso of tiit> lirsl section is also such as to afford some eliie 
 to till' ajje of tlie formations represented in it. 
 
 The Shii/iiviip Sirlrtt. — 'I'lie lowest erystalline, and presunuibiy Arclieun, 
 rocks lar;;ely represented in tlie western portion of tliis part of tlie Selkirk 
 raiif^o are evidently referalile to the Slmswap series of tiie lirst st'ction. 
 They consist chielly of gray gneisses, varying from nearly massive to quite 
 sdiistose, and in the latter case freipiently having tlieir division-phmea 
 thickly covereil with glittering miea. They are both hornhiendii' and mica- 
 ceous, hut the last-named mineral usually preponderates. Ortiioelase is 
 H|)pareiitly the most uhuudant feldspar, (|uart/. is nearly always well repre- 
 fienti'd and garnets are not infre(|nent. In numy places nearly half the 
 entire mu.ss of the roeks exposed consist.s of iiitriisivo or vein granite, with 
 pegmatitic or gri',ihitic tcmleneies. 
 
 Thr NIxconlii/i Serlen. — Overlying the hasal holo-erystalliiie series in the 
 Selkirk seoiion is a mass ot rocks of whieh the thickness is estimated at 
 l."),000 feet. These are dark-."olored and generally hiackish argiilite-schistft 
 nml ])hyllite8, representing variou"} stages in alteration between true nrgil- 
 litrs and micaceous schists. The rocks are usually rather finely fissile, with 
 glo.ssy and sometimes wrinkled surfaces, but often with nmch minute yet 
 visible mica on the division-planes. These planiis are in some cases evi- 
 dently due to cleavage, but ai'o often true bedding-plaiu's. The roeks are 
 usually calcareous, and fre(pUMitly hold tlun layers of da k-i)lnish or black 
 impure limestone, together with occasional layers of dark (juartzite. The 
 coloration i.s evidently due to carbomiceous matter, and pyrites crystals 
 are very common in certain zones. The only notable <liversity met with in 
 this otherwise liomogeneous nui.ss of rocks is fomid towards the base, where 
 (at the lower end of Albert canon) a bed of pure blue-gray crystalliiu' lime- 
 stone thirty feet or more in thickness occurs, and a short distance still lower 
 in the section, a si'ries of beds over 1,0(I(I feet in thickness, consisting cbieHy 
 of granular pale-gray (juartzites. The quartzites are sometimes flaggy and 
 generally more or less micaceous, and are interbedded as well as overlain 
 ami underlain by blackish micaceous argillites and layers of coar.sely niica- 
 ceous pale schists. 
 
 These rocks undoubtedly represent the Ni.scoulith series of the first column, 
 of which no e.N tended sections have yet been found in the interior plateau, 
 while to the eastward they certainly corresjiond in the main with the Bow 
 liiver series of the Rocky Mountains, for which a thickness of ]U,()0<> feet 
 was there ascertained, though the base of the series is never exposed in the 
 Rocky Mountains. 
 
l»KFlxiTii>\ (ir Tin: ski.kikk SICUIKS. 
 
 
 The Selkirk Serie*. — Betwci'ii tlic ('(iic^'oiii;; series iiiul tlic next ovcrlyiiiff 
 niOHH of l)e(lH in tlic Selkirk Heetion no distinct line of division, even of a 
 litholo^riciil clmriicler, lui.s been oliscrved, there lii,'in;r ii|i|>iirenlly, on the 
 contriiry, a ei)nsidcrai)l(! tliiukin'Hs of passa^'e hcds, in which the dark s<'iii.sts 
 of the lower series alternato witii jjray (|uart/.ite8 and ;,'ray >,'''"'*y •*'<■'>'■"*'•'* 
 characteristic of the npf)er Hcries. The «'stiinated thickness of this overlyinj,' 
 Hcries is •J.'),()()l) feet; and of its rocks the lu;;lier c. Mitral peakM of this part 
 of the ran;,'e, comprising mounts Sir Donald, .M;ir(Joinild, Tnpper, Hermit, 
 (,'liei)ps, Uoss peak and others, appear to he w hiiy eoinposeil. Litholog- 
 icnlly, it consists of a j^reat volume of gray schists ind gray <puirt/.ites, which 
 are oiicasionally somewhat dolomiti(!. The ;,irt7,it< s jjrolialdy iire|)onderate, 
 and vary in color from nearly white to gr md greenisli-i:ray, being seldom 
 dark in tint. They often, however, weather to pah luDwnish colors and pass 
 into conise grits and tine grained eonglomera*''s; and these gritri anil con- 
 glomerates have become more or U'ss 8cbi«toso in structure as a result of 
 pressure, which has also led to the development in tliem of much (iiie silvery 
 nii(ui. The schists vary in color from pule neutral-gray to L'reenishgray, 
 and from dull to silvery and lustrous, being in many cases apparently true 
 sericite-Hchists. They are sometimes wrinkled and contorted, ])articnlarly 
 on the east side of the main synclinal, where also they occasioinilly become 
 coarsely micaceous. To the east of this imiin synclinal and beyond the great 
 fault shown in the diagrammatic section (p. 174) they arc more crushed 
 anil altered and more highly micaceous than elsewhere, probably as a result 
 of the dynamic conditions to which they have been sul)jected in this region. 
 
 The rocks of this great series ap[)ear to re|)re.sent the Adams Lake serie-s 
 to the west, while they undoubtedly correspond, at least in a general way, to 
 the ('astle Mountain group of the Ilocky ^[ountain section on the east, for 
 which group Mr. McConuell ascertained a minimum thickness of 7,700 feet, 
 but found reason to i)elieve that its total volume in the western part of the 
 range approached 10,000 feet. 
 
 It will be understood front what has already been said that the line indi- 
 cated between this and the underlying series in the Selkirks is based entirely 
 on general lithological differences, while there is every reason to believe 
 that a plane of division drawn to correspond with that between the Castle 
 Mountain ;!nd Bow lliver series in the Rocky Mountains would lie several 
 thousand feet above the recognized summit of the Nisconlith series in the 
 Selkirks. In the Rocky Mou. 'ains, the lower Cambrian {Olciielliin) fauna 
 is known to be common to the lower part of the Castle Mountain and upi)er 
 j)art of the Row River series;* the sepanuimi being there made at the base 
 of the distinctly calcareous upper part of the Caml)rian, while certain rather 
 characteristic (unirtz-conglomerates observed in the upper part of the Bow 
 
 •This fiiiiiia is kiiiiwii to cliaianlerizn HevernI ilioiisaiul feel of tlie Ciistle Moiintiiiii .series, and 
 has been found aK well about 3,(kK) feet down in the upper part of tlie How River series. 
 
r 
 
 (i. M. DAWSON' — S'rnUCTl'llE OP TlIK SELKIHK UANGE. 
 
 River series of tiie Rocky Mountains are parnlleled by similar conglomerates 
 which abound in the upper series of the Selkirks. No unconformity has 
 been observed between the upper and the lower masses of strata in either 
 j)lace. 
 
 Thougli in tlie Selkirk section tlie lower of the two great series which have 
 been described resembles the Nisconlith of the interior plateau so closely as 
 to warrant extending the same name to it, the fact that the overlying mem- 
 ber of the section differs considerably from the Adams Lake series of the 
 interior plateau, while on the other side it pn)l)ably represents not only the 
 whole Castle ^Fountain group but also the upper part of the Bow River 
 series of the Rocky Mountains, renders necessary the application to it of a 
 provisional distinctive name. It is therefore proposed to refer to this rock- 
 mass as the Selkirk Series. 
 
 General Relations of the Cambrian. — Regarded as a whole, we find reason 
 to believe that the Selkirk section exhibits a great Cambrian fornnition 
 which (by analogy with the Rocky Mountains) includes the lower part of 
 the CambroSilurian and reaches down from it to and far beneath a horizon 
 at which the Olenelliis or lower Cambrian fauna has been found, with an 
 aggregate tiiickness of about 40,00(1 feet. 
 
 The comparatively pure limestones of which the Cambrian of the eastern 
 part of the Rocky Mountains is composed are replaced in the western part 
 of that range by rocks largely clastic in origin. This change in lithological 
 character appears to continue and to become still more marked and to be 
 accompanied by increasing thickness in the Selkirk range. ]N[uch of the 
 clastic material is silicious, and the introduction of an increased proportion 
 of such material nuiy i)e explained by considering it as a result of approach 
 to the shore line of Archeau rocks on the west. While the principal devel- 
 opment of contemporaneous volcanic products, whether in the Paleozoic, 
 Mesozoic or Tertiary, is conHned to a region west of the local Archean axis, 
 the writer is inclined to believe that a portion of the remarkable difference 
 found to occur in the western extension of the Cambriau may be due to the 
 inclusion in its rocks, on this side, of volcanic ash deposits or other fine- 
 grained volcanic materials, of which the cornj)usition was such as to favor 
 the subsequent production of sericitic or sericite-like schists. 
 
 Speaking generally, the great Cambrian formation of the Kocky Mountain 
 and Selkirk ranges shows many |)oiuts of rcsemblaiice to the Cambrian and 
 so-called "Algonkian " rocks of Utah ami Nevada, the resemblance being 
 particularly close in some respects to the series shown in the well-known 
 Wasatch section, in which more or lei<s distinctly micaceous schists are also 
 found. It is, further, not at all unlike the Cambrian of Wales, which, though 
 the organic renuiins are chieHy confined to some upper beds, has a thickness 
 of 25,000 feet and is believed to exceed this in Shropshire.* The provisional 
 
 
IXAl'1'LICABILITY OF THE TKini "AI.GOXKIAX. 
 
 173 
 
 estimate of tlie thickness of tlie Cnnibriun arrived at in tlie Selkirks is, how- 
 ever, greater than tiiat elsewhere known. 
 
 In a late paper on the stratigraphical position of the Olenelhis fauna,* 
 Mr. 0. D. Walcott has suggested that the 15ow River series of the Canadian 
 Koeky IMouiitains \m\\ he regarded as "Algonkian." He does not, liowcver, 
 appear to have been aware of the fact above alluded to, that the Olenellua 
 fauna eharaeterizes both the upper part of this series and the lower part of 
 the Castle INIountain gnjup. With this eircumstauce in evidence, together 
 with the apparently complete stratigrapiiical conformity of the two series, 
 the writer cannot but regard it as more in consonance with the conditions, so 
 far as these are known, and therefore as more j)hilosophical to Include, for 
 the present at least, the whole of this great conformable mass of rocks, to its 
 base, under tlie name Cambrian. In Utah and Nevada, where ^Ir. Wal- 
 cott's observations on the western Caml)rian have chiefly been made, it 
 seems that the beds classed as "Algonkian" likewise in general conform- 
 ably underlie those in which the Oleiicllns fauna is known, the conditions 
 being apparently in most cases similar to those here described. On the 
 ])r()pricty of the use of the new term in regions with which he is not per.son- 
 ally familiar the writer wishes to offer no opinion, but he may take the 
 opportunity of stating that he has met with no rocks in Canada to which its 
 application can at present bo considered appropriate, either in the interest 
 of precision in the expression of facts already a.scertained, or because of 
 the disc(/very of heretofore unrecognized relations as between the older 
 formations. 
 
 80 far as could bo definitely ascertained in the course of the rather 
 hasty examination upon which this paper is based, the lowest beds of the 
 Cambrian in the Helkirks (seen not far east of Albert Canon station) are 
 ill angular conformity to tlie Archean rocks (seen to the west of the same 
 station). The actual junction, however, remains to be studied, as there is 
 here a gap in the section on the lino of railway. In the meantime it may be 
 stated that, notwithstanding the appearance of conformity, there is reason to 
 believe llial a great break in time is here passed over; for, although coarse, 
 glittering micaceous schists are found in some parts of the Cambrian, the 
 rocks of the lower .series differ markedly even from these in their completely 
 crystalline character. The essential diversity in age of the two series is fur- 
 ther shown by the circumstance that the highest rocks of the Archean here 
 met with do not include the notably silicious beds, the calcareous gneisses 
 and the marbles which characterize the upper parts of this ."vstem n« ex- 
 posed on Kootanio lake ami near Shuswap lake. It is also found that the 
 very numerous granitic veins which everywhere cut the Archean rocks do 
 not enter the overlying Cambrian strata, while a large quantity of pale-pur- 
 
 • Am. .luiirii. Sel., ■iiiil ser., vol. X.XX VIII, ISSl) ,>. .Vi. 
 XXVI— Hi'1,1,. litiii.. Soc. Am,, Vol,. ;;, is'.iii, 
 
Ir^" 
 
 174 
 
 G. ^r. DAWSON' — STRUCTURE OF THE SELKIRK RAXOE. 
 
 plisli, sli^flitly oi)alesceiit quartz occurring in the con- 
 jrlomcrutes and (juartzites of the (.'anibrian seems 
 iin(l()ul)te(lly to have l)een derived from the denuda- 
 tion of tliese very granitic veins. 
 
 Neiver Rocks. — On tlie eastern side of the Selkirk 
 range certain rocks occur wliich are supposed to be 
 equivalent to the GraptoUie-heiw'mg siiales and Ilnhj- 
 sites beds of the adjacent Kocky Mountains. As, 
 however, tiie reference of these beds must as yet be 
 considered doubtful, on account both of the absence 
 of fossils and of the unusiuiliy disturbed character 
 of this j)art of the section, nothing more need here 
 be said respecting them. 
 
 The Devono-Carboniforous, Carboniferous, Triassic 
 and Cretaceous strata entering into the composition 
 of neighboring j)arts of the Kocky Mountains are jjuimnsli 
 nowhere seen in this part of the Selkirka. 
 
 Structure. 
 
 Kespecting the structural features of the section 
 as a whole, little need be atlded, as, in so far as these 
 may be considered to have been determined, they 
 are rather simple. The western part of the Seikirjc 
 range, fur a wiilth of about seventeen miles, is essen- 
 tially composed of Archean and granitic rocks, which, 
 it may be added, are continued to the west of this 
 part of the Helkirks across the Columbia range for a 
 further distance of about forty miles. These rocks 
 often li(! at low, undulating angles, though they are 
 occasionally nuich contorted. Above these, to the 
 eastward, is the lower meud)erof the Cand)rian which 
 has been referred to as the Nisconlith series. This 
 forms a synclinal, of which the western side lies at 
 a low angle, while the eastern side i;, steep, the axis 
 being found near Illecillewaet station. To the east 
 of the synclinal is a rather sharp anticlinal, the 
 summit of the dark-c(dored beds of the Nisconlith 
 series passing out of sight on the east(!rn side of this 
 fold near the 41Mtli mile-post on the railway. 
 
 The next great synclinal, which coincides witii the 
 highest parts of the*range, appears to have a triiiis- 
 vcrse width of about tliirteen miles. The rocks con- 
 
 l\. 
 
 *'C. 
 
 a!io)siaADH!iL: 
 
OROGRAPIiy OF TlIK SKLKIUK KAXGE. 
 
 17." 
 
 tained in it are those of the Selkirk series, wliieh is believed to represent 
 the upper part of the Bow River series, tojrcther with the whole of the Castle 
 i\[oiintain group of the Rocky IMountain section. The position of the main 
 axis of tiiis synclinal nearly corresponds with Loop creek, on the railway, to 
 the west of (ilacier station, while a sul)ordini*te synclinal trough runs im- 
 mediately to the east of the same station and nearly coincides with the actual 
 watershed in the pass. 
 
 The eastern edge of tiiis synclinal is believed to be bounded by a great 
 fault, which is supposed to cut the line of i-ailway near Cedar creek (about a 
 mile and a half below Surprise creek) and to run on southward along the 
 upper part of Beaver vrtlley. This fault seems to have the character of a 
 number of those found by jMr. McConnell in an adjacent part of the Rocky 
 jMountains, viz., that of a fractured anticlinal, tiirust up on the west side in 
 c()nse(juence of ])ressure acting from that direction. 
 
 To the east of this great fault, the section shown in figure 1 must yet be 
 considered largely hypothetical, as the structure here becomes more compli- 
 cated and there is reason to suspect further extensive faulting. There are, 
 however, grounds for the belief that, in a wide additional synclinal on this 
 flank of the range, together with tiie repetition of a great part of the Selkirk 
 group, still higher strata representing the Grap(ol!te-hcnv\ng shales and the 
 Ihlijsileii beds of 'he Rocky Jlountains are included. The section ends on 
 the v^ast at the upper Columbia valley, the line of which is coincident with an 
 important anticlinal exposing rocks of tlu; Castle Mountain series, which dip 
 westward into tiio base of the Selkirk* and eastward into tlie opjwsite base 
 
 of the Rockv Jlountains. 
 
 Thickne.ss. 
 
 If the writer is correct in attributing a total thickness of about 40,000 feet 
 to tiie Cambrian i witli such part of the Cambro-Silurian as may be included 
 in the upper portion of the Castle jMountain group) of the Selkirk range, 
 the entire thickiuss of the Paleozoic obtained by adding to tliis that of the 
 remaining higher meml)ers of the adjacent part of the Rocky Mountains 
 would be about 49,000 feet. Supplementing this with the thickness of the 
 Kootanie and other formations of the Cretaceous, seen either in the Rocky 
 ^lountains oi" in the neighboring foot-hills toward the east, we obtain a 
 total of 69,000 feet. 
 
 Though, however, the sections which give this enormous aggregate are all 
 (•om[)rised within a distance, measured across the axis of disturbance, of little 
 more than 100 miles, it is imrrobable that the whole of the beds in their 
 maximum thickness ever formed a single column. The Cambrian evidently 
 thickens greatly at its western nuirgin, where not only has the upper part of 
 the I'aleozoic not yet been found, but where also there is reason to believe 
 
■mm 
 
 170 
 
 G. M. DAWSON — STRUCTUIIE OF THE SELKIRK RANGE. 
 
 that tlie very thick Cretaceous formntions never extended. It must further 
 be borne in mind that tiie adtual wiiUii of 100 miles measured across this 
 fohled and faulted region represents a zone of very probably double this 
 width of the surface as it was antecedent to the great folding and faulting. 
 In this zone the line of maximum sedimentation a])pears to have moved 
 progressively eastward, or away from the local Archean laud, in the later 
 periods. 
 
 DISCUSSION. 
 
 Dr. J. W. Spknceu: I desire to again* claim priority for the name 
 Algonkian, on the ground that before its publication I had used the term 
 "Algoncjuiu " to designate an episode in the (Quaternary history of the 
 region of the Great Lakes. 
 
 Mr. G. K. Grr.ii.KKT: While the two names referred to by Dr. Spencer 
 are based on the same root, one has the adjective form and the other the 
 nominal, and (•( , I'usion is thus avoided. The simultaneous and unobjection- 
 able use of nouns and adjectives etymologically identical for different ele- 
 ments of geologic classihcation is illustrated in the case of the "Huron 
 siiale " and the " Huronian system," and in that of " Erie clay " or "Erie 
 shale" and the " Eriau period " or system. The use of "Erie shale" for a 
 Paleozoic fornnition conflicts with the use of " Erie clay" for a IMeistocene 
 formation, but neither conflicts with Sir William Dawson's terra "Erian." 
 
 *Cf. Dull, tieol. .S')C. Ani,, vdI, 1, 1889, p. 2.)S, note. 
 
 R' 'JAMES 
 
 p. O. BOX 17$ 
 *'ANCOUvp«t, CANADA 
 
 *ooi<» OUT oF~H»iNT "1 an 
 

 .^/c" 
 
 i 
 
J|iU!JllVaBPAlJ-l»LUMii*JI^^-'W?J!U.H^^!JijkJJLaWj^^ 
 
 fm