6Q G. M. DAWSON ROCKY MOUNTAIN REGION IN CANADA 



siliferous at several horizons, and appears to pass up at its summit into 

 the Ordovician.* 



Following the general direction of the Laramide range northwestward, 

 Cambrian rocks similar to those of the Bow pass are now known at in- 

 tervals for man}' hundred miles, and it is probable that they will be found 

 to form a continuous or nearl}' continuous belt. Both groups are recog- 

 nized with practically identical characters on the Yellow Head pass and 

 on the Finlay river. The Misinchinca schists of my report of 1879, no 

 doubt represent the Bow River series, and similar rocks are again found 

 at the sources of the Pelly branch of the Yukon. f 



Passing now to the next mountain S3"stem, to the southwest of the 

 Laramide range and parallel with it — the Gold ranges — we find in the 

 Selkirk mountains a great thickness of rocks that have not yet jdelded 

 any fossils, but appear to represent, more or less exactly, the Cambrian 

 of our typical section. Resting on the Archean rocks of the Shuswap 

 series is an estimated volume of 15,000 feet of dark gray or blackish 

 argillite schists or phyllites, usuall}' calcareous, and toward the base with 

 one or more beds of nearly pure limestone and a considerable thickness 

 of gray flaggy quartzites. To these, where first defined in the vicinit}'^ 

 of the Sliuswap lakes, the name Nisconlith series has been applied.'! The 

 rocks vary a good deal in different areas, and on Great Shuswap lake 

 are often locall}' represented by a considerable thickness of blackish 

 flaggy limestone. It other portions of their extent dark-gray quartzites 

 or gray wackes are notably abundant. Their color is almost everywhere 

 due to carbonaceous matter, probably often grai)hitic, and the abundance 

 of carbon in them must be regarded as a somewhat notable and charac- 

 teristic feature. These beds have also been recognized in the southern 

 part of tlie West Kootenay district and in the western portion of the 

 Interior plateau of British Columbia. 



The Nisconlith series is believed, from its stratigraphical j^osition and 

 because of its lithological similarity, to represent in a general way the 

 Bow River series of the adjacent and ])arallel Laramide range, but there 

 is reason to think that its upper limit is somewhat below that assigned 

 on lithological grounds to the Bow River series. 



Conformably overlying the Nisconlith in the Selkirk mountains, and 

 blending with it at the junction to some extent, is the Selkirk series, 



* For descriptions of the fossils from these beds, the following authors may be referred to : 

 C. Rominger, Proc. Acad. Nat. Sci., Phila., 1887, pp. 12-19; C. D. Walcott, Proc. U. S. Nat. Mus., 

 1889. pp. 141-440 ; J. F. Whiteaves, Can. Rec. Sci., 1892, vol. v, pp. 205-208 ; F. R. C. Reed, Geol. Mag., 

 1899, Dec. 4, vol. vi, pp. 358-361 ; G. F. Matthews, Trans. Roval Soc. Can., series 2, vol. v, sec. 4. 



t Annual Report Geol. Surv. Can., vol. xi (N. S.), p. 31 D. Ibid., vol. vii, p. 34 C\ Report of 

 Progress, Geol. Suvr. Can., 1879-80, p. 108 B. 



X Annual Report Geol. Surv. Can., vol. iv (N. S.), p. 31 B. Bull. Geo!. Soc. Am., vol. ii, p. 170. An- 

 nual Report Geol. Surv. Can., vol. vii (N. S.), p. 31 B. Shuswap map-sheet, Geol. Surv. Can. 



