NO. 12 CAMBRIAN FORMATIONS ROBSON PEAK DISTRICT 



343 



(pp. 341, 342) and in the detailed sections (pp. 336-340) for the 

 Robson section and for the Bosworth section in my paper on the 

 Cambrian sections of the Cordilleran area.^ 



COMPARATIVE STRATIGRAPHIC SECTIONS 



ROBSON DISTRICT ^^O^NT BOSWORTH 



SECTION 



Formations 



Formations 



Feet 



Upper Cambrian 



Lynx 2,100 



Titkana 2,200 



Miimm 600 



Middle Cambriani ^'^}''' ''1?^ 



' 1 atay 800 



Chetang 900 



•- 6,200 



Feet 



1,375 Sherbrooke 



360 Paget 



1.855+ Bosworth 



3.590+ 



2.728 Eldon 



640 .... Stephen 

 1,595 . . .Cathedral 



4.963 



There are strong points of resemblance between the McNaughton 

 and Fairview formations, both being formed of layers of quartzitic 

 sandstone that weather to a dark, rusty-brown color and both being 

 unconformably superjacent to the sandstone of the Belt series. 



One of the most noticeable differences is in the thickness of the 

 massive arenaceous limestones, in the Robson section which is much 

 less than in the Bosworth section. There is a thickness of only 

 1,400 feet (422.8 m.) in the Middle Cambrian, while in the Bosworth 

 section the Eldon and Cathedral arenaceous limestones of the Middle 

 Cambrian have a combined thickness of 4,333 feet (1,308.5 m.). 



Future study of the Robson section and discovery of other fossil- 

 bearing beds will undoubtedly lead to a shifting of the lines of 

 demarcation, but the larger divisions of the section will probably be 

 preserved. 



' Smithsonian Misc. Coll , Vol. 53, No. 5. 1908, pp. 204-216. 



