NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 297 



On Mount Assiniboine, the Mount Whyte formation is concealed by 

 ice, snow, and talus, or exposed in practically inaccessible cliffs, but 

 in the spur or ridge that extends to the eastward from the main peak 

 toward Wonder Pass, excellent exposures may be examined. 



The profile of the section beneath the Cathedral cliff-forming lime- 

 stone, through the Ptarmigan and Mount Whyte formations, is usually 

 a series of broken cliff's. These topographic features continue for 

 many miles both north and south of Mount Assiniboine. On all the 

 higher peaks, the Ptarmigan, Cathedral, or other superjacent Middle 

 Cambrian limestones form cliffs above the Mount Whyte. 



To the northwest of Mount Assiniboine, the Mount Whyte forma- 

 tion forms a broken terrace on the front of the range, or is partly 

 merged into a great cliff with the Cathedral and Ptarmigan limestones ; 

 usually, however, it stands out from the strata above by change in 

 topographic outline or in color. 



A/[IDDLE CAMBRIAN 



Cathedral Formation p^^^ j^^^^^^^ 



I. Light and dark gray arenaceous limestone in massive 

 layers that form cliffs and, on the summits of ridges, 

 slender pinnacles, massive irregular broken walls, and 

 often fantastic figures Estimated i ,000 -f- 304.8 4- 



Ptarmigan Formation 



I. Bluish-gray, arenaceous limestone, alternating with 

 bands of dark, bluish-black limestone made up of 

 thin layers Rough estimate 350 106.7 



Fauna. — (63n) : 



Poliella chilo Walcott 



la. Buff-weathering, rough, gray, arenaceous limestone.... 26 7.9 



Total Ptarmigan formation 376 114.6 



LOWER CAMBRIAN 



Mount Whyte Formation 



I. Gray oolitic limestone in layers 2 to 8 inches (5 to 



20.3 cm.) thick 23 7.0 



Fauna. — (62w) : 



Archaeocyathits atreiis Walcott 



Kutorgina cf. cingulata (Billings) 



Paterina labradorica (Billings) 



Jamesella lowi Walcott 



Acrotrcta sagittalis taconica Walcott 



Helcionella elongata Walcott 



Scenella varians Walcott 



Hyolithes billingsi Walcott 



Crepicephalus cecinna Walcott 



Kochiella cleora (Walcott) 



