u8 



order. The measurements and estimates are founded 

 on considerable, more recent field-work supplementing 

 the reconnaissance studies of G. M. Dawson. [5, p. 62]. 



The total of the maximum thicknesses is colossal 

 (135,000 feet (41,150 m.), including 25,000 feet (7,620 m.) 

 of volcanics), but there can be no doubt that it is correct 

 as to the order of magnitude. Notwithstanding all possible 

 errors of mensuration, it seems clear that the Beltian- 

 Paleozoic geosynclinal prism of the Selkirk- Rocky Mountain 

 region had a thickness greater than 50,000 feet (15,240 m.). 

 Dr. J. A. Allan has found more than 40,000 feet (12,192 

 m.) of conformable sediments in the Rocky mountains. 

 The still older strata of the Selkirks are nearly or quite as 

 thick. 



TABLE OF CORDILLERAN FORMATIONS. 



System. 



Formation. 



Thickness. 



Feet. 



Metres. 



Recent and 



Pleistocene 



Fluviatile, lacustrine, 

 glacial 









Unconformity. 







Oligocene (?) 



Kamloops volcanic group 



Tranquille beds (largely 



tuffs) 



3,000+ 

 1 ,000 



914 + 

 305 





Unconformity. 



Eocene 



Coldwater group (con- 

 glomerate, sandstone, 

 etc.) of Interior 



5,000 







1.524 





Rhyolite porphyry at 









Unconformity 







