[schofield] rocky MOUNTAIN TRENCH 67 



metamorphosed extension of the Purcell series across the Purcell 

 trench as originally shown on the West Kootenay map. The meta- 

 morphism is due to batholithic invasion which in this locality appears 

 to conform closely to the regional structure, the formations swinging 

 to parallel the granite contacts. The terrane includes the folded 

 domed Kitchener, Creston, and Aldridge members of the Purcell series 

 cut, here and there, by granite and complementary dykes from the 

 large adjacent masses of granite." The field facts from which the 

 above conclusion was drawn are not given. 



In 1914, the author^ examined the area west of Kootenay Lake 

 and was unable to detect the great fault described by Daly^ which 

 separated the Beltian rocks from the Priest River terrane and from 

 the field facts came to the conclusion that the Priest River terrane 

 in part at least is a metamorphosed equivalent of the Aldridge, since 

 in the area examined the Priest River terrane of Daly was a con- 

 formable part of the Aldridge quartzites and the two formations 

 passed into each other by gradual transition. The Priest River 

 terrane and the Aldridge quartzites differed only in degree of meta- 

 morphism. 



In studying the section exposed along the Canadian Pacific 

 Railway from Golden to Revelstoke, Daly^ includes in the Shuswap 

 formations designated by Dawson as belonging to the Cambrian the 

 Niskonlith and the Adams Lake series. The Beltian, according to 

 Daly, rests unconformably on the Shuswap terrane and it may be 

 stated that, although Daly's evidence was examined in the field by 

 several observers, they were not convinced that such an unconformity 

 exists at the point designated. 



Without submitting any facts to support his statement Drysdale* 

 ventures the following opinion on the above section. 



"Future investigation may prove that both the Adams Lake and 

 Niskonlith series of the Shuswap and Albert Canyon regions are a 

 closely folded and faulted series of Cambrian and Post-Cambrian age 

 similar in lithology and chronological sequence to the south Kootenay 

 sections which have been mapped in more detail." 



In 1917, Drysdale^ found Upper Palaeozoic fossils in the Laurie 

 formation which Daly^ had included in the Beltian. The Laurie 

 formation is 15,000 feet thick, and since the horizon in which the 



1 Schofield, S. J., Geol. Surv., Can., 1914, p. 31. 



^ Daly, R. A., Geol. Surv., Can., Mem. 38, 1912. 



' Daly, R. A., Geol. Surv., Can., Mem. 68, 1915, p. 10. 



'' Drysdale, C. W., Geol. Surv., Can., Sum. Rept., 1916, p. 61. 



6 Burling, L. D., Bull. Geol. Soc. Am., vol. 29, 1918. 



• Daly, R. A., Geol. Surv., Can., Mem. 68, 1915, p. 67. 



