(AMI'.KIAN 67 



with ail estimated thickness of 25,000 feet, consisting, where not rendered 

 micaceous by pressure, of gray and greenish-gray schists and quartzites, 

 sometimes with conglomerates and occasional intercalations of blackisli 

 argillites like those of the Xisoonlith. These rocks are evidentl}^ in the 

 main equivalent to the Castle Mountain group, representing that groui) 

 as affected b}" the further and nearly complete substitution of clastic 

 materials for the limestones of its eastern development. 



In the vicinity of Shuswap lakes and on the western border of the 

 Interior plateau, the beds overlying the Nisconlith and there occu})ying 

 the place of the Selkirk series are found to still further change their 

 character. These rocks have been named the Adams Lake series.''^ They 

 consist chiefly of green and gray chloritic, felspathic. sericitic, and some- 

 times nacreous schists, greenish colors preponderating in the lower and 

 gra\^ in the upper parts of the section. Silicious conglomerates are but 

 rarely seen, and on following the series beyond the flexures of the moun- 

 tain region it is found to be represented by volcanic agglomerates and 

 ash-beds, with, diabases and other effusive rocks, into which the passage 

 may be traced by eas}^ gradations.f The best sections are found where 

 these materials have been almost completely foliated and much altered 

 b\" dynamic metamorphism, but the approximate thickness of this series 

 is again about 25,000 feet.]: 



The upper part of the Cambrian system, above the Bow River and Nis- 

 conlith series, may thus be said to be represented chiefly by limestones 

 in the eastern part of the Laramide range, calc-schists in the western part 

 of the same range, quartzites, gray wackes, and conglomerates in the Sel- 

 kirk mountains, and by volcanic materials still further to the west. It 

 is believed that a gradual passage exists from one to another of these 

 zones, and that the finer ashy materials of volcanic origin have extended in 

 appreciable quantity eastward to what is now the continental watershed 

 in the Laramide range. No contem[)oraneous volcanic materials have, 

 however, been observed in the underlying Bow River or Nisconlith series. 



The beds first definitely referred to theCambriaii in the Rocky Moun- 

 tain region of Canada are those found near the International boundary 

 in the vicinity of the South Kootenay pass.§ These were further exam- 

 ined at a later date, as described in the report of the Geological Survey 

 of Canada for 1885, || and some additional observations in regard to them 

 are given by Mr J. McEvoy.^ 



* For the Selkirk and Adams Lake series see references above given for Nisconlith series, 

 t Annual Report, Geol. Surv. Can., vol. vii (N. S.), p. :i.') B. 



t Comprising greenish schists 8,100 feet, grayish schists 17,100 feet. In Bull. Geol. Soc. Am., 

 Tol. ii, p. 1G8, the thickness is given in error at half the aV)Ove. 

 g Geology and Resources of the 49th Parallel, p. GS. Geol. Mag., Decade II, vol. iii, p. 222. 

 n Pp. ao B-42 B. 

 U Summary Report, Geol. Surv. Can., 1899, p. 97 A. 



