296 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Origin of columnar structure. — The origin of the columnar struc- 

 ture was presumably the same as for the cellular, pipe-like Graysonia 

 and Copperia of the pre-Cambrian/ which I considered owed their 

 origin to the agency of algae closely allied to the Cyanophyccae (blue- 

 green algae). 



MOUNT ASSINIBOINE REGION 



Wonder Pass is on the Continental Divide between Gog Lake and 

 Marvel Lake on a branch of Bryant Creek, a tributary of Spray River. 

 The Pass is about i8 miles (28.9 km.) southwest of Banff, Alberta, 

 and 3 miles (4.8 km.) northeast of Mount Assiniboine. 



The measured section is from the summit of the ridge down to the 

 level of Gog Lake (7,200 feet, 2,194.6 m., above sea level). The 



Middle Cambrian 

 Cathedral Limestones. 



Fig. 29. — Diagrammatic section of the Assiniboine massif showing the 

 thrust fault, on the line of Mount Assiniboine and Mount Wedgwood. The 

 massive Lower Cambrian quartzites are thrust over the Devonian limestones. 

 At Wonder Pass, about 3 miles (4.8 km.) east of Mount Wedgwood cliff, a 

 narrow band of the pre-Cambrian Hector arenaceous shales occurs between 

 the basal Cambrian conglomerate and the thrust fault. (See pi. 60, figs. 1-2.) 



summit of the ridge is formed of massive-bedded arenaceous lime- 

 stones of the Cathedral and Ptarmigan formations. About 400 feet 

 (121.9 m.) of the arenaceous limestone remains on the north section 

 of the ridge, and 1,500 feet (457.2 m.) or more on the south end, 

 which rises to 9,400 feet (2,865.1 m.) at Naiset " Mountain. I en- 

 deavored to examine the strata of the Cathedral, but just after reach- 

 ing the top of the Mount Whyte formation, the first snow squalls 

 came and drove me out of the region for the season. 



' Smithsonian Misc. Coll., Vol. 64, No. 2, 1914, pp. 100-104. pis. 17-19. 



^ The name Naiset, Indian name for Sunset, was proposed in 1916 for the 

 mountain west of Wonder Pass, the same being the northeastern end of the ridge 

 of Mount Assiniboine. This name has been approved by the Geographic Board 

 of Canada. 



