364 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Feet Meters 



At the Pass the valley is essentially the same type 

 as the valley of Bow River near Lake Louise Station. 

 In both, the valley is eroded in the Beltian series of 

 impure sandstones, and the Cambrian sandstones and 

 limestones form high, bold mountains to the north 

 and south of the valley. 



SUMMARY OF ROBSON DISTRICT SECTION 



ORDOVICIAN 

 RoBSON Formation 



I. Massive- and thin-bedded, gray limestones that are 



partly siliceous, arenaceous, and dolomitic 500 152.4 



OZARKIAN 

 Chushina Formation 



I. Thin-bedded, gray limestone 1,500 457-2 



UPPER CAMBRIAN 

 Lynx Formation 



I. Thin-bedded, gray and bluish-gray limestone, with bands 



of shale 3,500 1,066.8 



MIDDLE CAMBRIAN 



TiTKANA Formation 



I. Massive beds of thin layers of bluish-gray limestone, 



interbedded with bands of dolomitic limestone 2,200 670.6 



Tatei Formation 



I. Massive-bedded, gray arenaceous limestone 800 243.8 



Chetang Formation 



I. Bluish-gray, thin-bedded limestones 900 274.3 



Total Middle Cambrian 3,900 1,188.7 



LOWER CAMBRIAN 

 Hota Formation 



I. Gray arenaceous limestone, alternating with ^massive 

 quartzitic sandstone (Mesonacidae), Olenellus, Cal- 

 lavia, etc 800 243.8 



Mahto Formation 



I. Massive-bedded quartzitic sandstone, with bands of sili- 

 ceous shale 1,800 548.7 



Tah Formation 



I. Siliceous shale and interbedded siliceous limestones.... 800 243.8 



