CAMBRIAX CORDILLERAN SECTIONS— WALCOTT 



169 



uplift, and thence north into Alberta, east of the Rocky Mountain 

 front, where all traces of it are lost beneath the covering of Tertiary 

 and Cretaceous rocks. In the vicinity of the international boundary 

 (49th parallel) an uplift of pre-Cambrian (Beltian) strata appears 

 to have largely prevented Cambrian sedimentation in northwestern 

 Montana and northern Idaho. The faunas of the sections to the 

 north in British Columbia and to the south in Utah clearly prove 

 that the seas in which they lived were connected, but how or where 

 we do not know. 



In the following diagram the general relations of the sections are 

 shown : 



Table Shoxving Sfratigraphic Position in the Cambrian Syst-em of Five of the 



Sections Described 



The House Range section, supplemented by the JUowcr Cambrian 

 sections of western Nevada and southeastern California, 230 miles 

 (370.07 km.) west-southwest, gives a total of over 13,000 feet 

 (3962 m.) of strata with Cambrian faunas throughout. If the Big 

 Cottomvood section, 140 miles (225.26 km.) to the northeast of the 



