142 



With the exception of the Sir Donald and upper- Ross 

 quartzites, Cambrian strata are absent in the railway 

 section west of the Rocky Mountain trench. The enor- 

 mous development of the Cambrian in the Rocky mountains 

 was demonstrated by McConnell and Dawson. More 

 recent studies by Walcott and Allan have led to its detailed 

 subdivision, as here summarized. 



Columnar Section of the Rocky Mountain Cambrian. 



•- 



Formation. 



Thickness. 





Feet. 



Metres. 





fOttertail limestones 



| Chancellor shales, etc 



1.725 

 4,5oo 



. 1-375 

 360 



i,855 



2,728 



640 



i,595 



390 



2,705 



105 



600 



526 



1,372 



419 



no 



Upper 



\ Sherbrooke limestones 



1 Paget limestones 





[Bosworth limestones, etc 



[Eldon limestones 



565 



831 

 196 

 486 



119 



824 



32 



183 



Middle 



\ Stephen limestones, etc 



[Cathedral limestones 





fMt. Whyte shale, etc 



Lower 



1 St. Piran quartzitic sandstone 

 J Lake Louise shale 





(Fairview sandstone, grit, etc. . 





18,578 



5,663 



On pages I74ff. will be found Dr. Allan's summary 

 description of these formations. 



Ordovician System. 



Ordovician strata are represented at the railway section 

 only within the limits of the Rocky mountains and the 

 floor of the Rocky Mountain trench. These beds once 

 extended over the site of the Purcell range and over much 



