1 83 



They are usually calcareous in composition, but certain 

 layers are argillaceous and arenaceous. The lower contact 

 of this series is sharply denned but at the top of the series 

 the beds change to a shaly limestone difficult to distinguish 

 from the overlying limestone. The shales weather out 

 more easily than the limestone, so that a depression is 

 always formed where these shales cut across a ridge. A 

 leading fossil is Spirijer centronatus. 



Pennsylvanian. 



Upper Banff Limestone. — There are over 2,300 feet 

 (701 m.) of beds included in this formation, which is well 

 exposed in Sawback and Cascade ranges. The series is 

 shaly at the bottom, but more massive towards the top. 

 Cherty lenses and cherty shale interbedded with the 

 lower shaly limestone help to distinguish this formation 

 from the shales below. Fossils e.g., Spirijer rockymon- 

 tanus, are quite abundant throughout the lower beds in 

 this series. 



Rocky Mountain Quartzite. — This quartzite lies 

 directly on the Upper Banff limestone. It represents a 

 very sudden shallowing of the water, which, however, 

 was not rendered muddy. The section in the Sawback 

 range gave 800 feet (244 m.) as a maximum thickness. 

 There is a rapid thickening of this formation to the east 

 so that at Lake Minnewanka, 12 miles (19 km.) to the 

 east, there are 1,600 feet of quartzite exposed. Certain 

 portions of the formation are quite fossiliferous. These 

 fossils e.g., Euphemus carbonarius, can most readily be 

 found on the weathered surface. 



This is the uppermost formation in the Carboniferous. 

 The lower two formations have been grouped as Mississip- 

 pian in age, while the upper two correspond to the Penn- 

 sylvanian. [9, p. 147]. 



PERMIAN. 



Upper BanflE Shale. — This formation lies conformably 

 upon the quartzite and consists of a series of brown, 

 calcareous and arenaceous, often sun-cracked shales 

 interbedded with thin layers of sandstone. The shales 

 weather out more easily than the underlying formations, 

 forming valleys such as those between the Cascade, Ver- 

 milion Lake, and Sawback ranges. More than 1,400 feet 

 35069— 6a 



