70 



THE ROYAL SOCIETY OF CANADA 



Glacier Division 



(Selkirk Series of Dawson) 



Albert Canyon Division 



(Niskonlith Series of Dawson) . 



Conformity 



Ross quartzite (lower part) 2,500+feet 



Nakimu limestone 350 " 



Cougar formation 10,800 " 



Laurie formation 15,000 " 



Illecillewaet quartzite 1,500 " 



Moose metargillite 2,150 " 



Limestone 170 * 



Basal quartzite 280 " 



Unconformity 

 Shuswap terrane. 



The discovery of upper Palaeozoic fossils in the Laurie formation 

 by Drysdale^ in 1917 disturbs our conception of this Beltian section 

 as described by Daly and if Daly's structures of the Selkirk Mountains 

 be correct, the formations above the Laurie formation cannot be 

 Beltian, but upper Palaeozoic at least. Dawson^ considered the 

 rocks of the Laurie formation to have a synclinal structure, whereas 

 Daly considers the structure to be monoclinal. From the brief dis- 

 cussion above, it will be seen that much remains to be done before the 

 section of the Selkirk Mountains along the Canadian Pacific Railway 

 can be definitely placed in the geological column. Before this is 

 accomplished, it is extremely difficult, if not impossible, to determine 

 the throw of the great fault at Golden, which was a determining factor 

 in the formation of the Rocky Mountain trench at this point. 



Cambrian 



The Pre-Cambrian sediments, in great part of continental origin, 

 are overlain unconformably by the Cambrian formations of marine 

 deposition. Locally these two terranes are marked by a disconformity, 

 but from a regional point of view, unconformable relationships may 

 be said to hold. 



From a study of the sections given below, it can be seen that the 

 Cambrian formations increase in thickness from north to south and 

 from west to east. The southern sections at North Kootenay Pass, 

 and at Elko, show the Middle Cambrian formations only, with the 

 Devonian resting with a disconformity upon them. At Canal Flats 

 the Upper Cambrian makes its appearance, while on the main line of 

 the C.P.R. at Field, the Lower, Middle, and Upper Cambrian forma- 

 tions together with the Ordovician and Silurian are represented in 

 relatively great thicknesses. 



1 Burling, L. D., Geol. Soc. Am., vol. 29, 1918, p. 145. 

 * Dawson, G. M., Geol. Soc. Am., vol. 2, 1891, p. 174. 



