68 G. M. DAWSON — ROCKY MOUNTAIN KEGIOX IN CANADA 



A thickness of at least 11,000 feet of sandstones and shales of red, gray, 

 and greenish colors, freqiientl}'' alternating and including several con- 

 temporaneous trap flows, occurs between the Continental watershed and 

 the Flathead river. This series has not been traced into connection with 

 the sections previousl}'' described, but it shows some resemblance to the 

 Selkirk and Castle Mountain groups. The occurrence of blackish cal- 

 careous argillites and sandstones at the base may indicate the presence 

 of the Bow River series there, while a limestone at the top of the section 

 in this part of the mountains may prove to be that of the Castle Moun- 

 tain group.* 



Along the eastern borders of the Coast ranges, in southern British Co- 

 lumbia, is a very considerable volume of argillites with some limestone 

 and altered volcanic products, all more or less schistose or slaty. These 

 were originally described by Selwyn as the "Anderson River and Boston 

 Bar group." t They may be Cambrian, l)ut it has not yet been found 

 possible to separate them from newer Paleozoic rocks with wliich they 

 are associated. 



Additional Cambrian areas will no doubt also eventually be defined 

 in the far north, including some of the rocks met with on the Stikine 

 and Dease rivers and in the Klondike district.^ 



Ordovicjan and Silurian 



As already noted, the upper part,of the Castle Mountain group in the 

 Laramide range contains fossils;referable to tlie Ordovician. In the same 

 western part of tlie range, 1,500 feet or less of l)lack shales lies above these, 

 containing grai)t()lites that liave been referred to the Trenton-Utica 

 fauna by Professor Lapworth.g The same grai)tolitic fauna was found 

 in 18S7 on the Dease river, not far south of the 60th parallel of latitude.|| 



Above thegraptolitic })eds in the Bow Pass section, is a thicknessof 1,300 

 feet or more of dolomites and quartzites, containing Halysites catenulatus 

 and a few other forms that are believed to ])e Silurian.*[ 



The above-mentioned localities are the only ones in which Ordovician 

 or Silurian rocks have been discovered in the entire region under review. 



Devonian 



East of the continental watershed, on the Bow pass, Mr McConnell's 



♦Annual Report,'GeoI. Surv. Can., vol. i (N. S.), pp. 50 B, 51 B. 



t Hiid., vol. vii, pp. 38 B. 43 B. 



X Ibid., vol. iii (N. S.), pp. 32 B, 94 B. Summary Report, Geol. Surv. Can.. 1899, p. 18 A. 



g .Annual Report, Geol. Surv. Can., vol. ii, (N. S.), p. 22 D. 



Ij Ibid., vol. iii, p. 95 B. 



^ Ibid., vol. ii, p. 21 D. 



