[dowling] cretaceous SEA IN ALBERTA 39 



One of the subdivisions, the Wapiti River sandstones, referred 

 to above, is here correlated with the upper part of the Belly River. 

 It is a series of sands and shales containing coal seams overlying the 

 Smoky River shales, and is exposed in many stream channels on the 

 plateau cut through by the Wapiti river. This formation has pre- 

 viously been classed as Laramie in age, indicating that it is a series 

 of transition beds from the Cretaceous to the Tertiary. This cor- 

 relation does not seem to be definite enough since as before noted 

 there are marine deposits above it which would suggest its being 

 nearer in date of deposit to the upper part of the Belly River. Its 

 correlation with the Edmonton has been suggested on account of 

 similarity of deposits. This is equally true of a comparison with the 

 Upper Belly River beds, but the probability of marine water reaching 

 this area decreases very fast after the time represented by the advance 

 of the Upper Pierre sea ; that is, the probability of the marine beds 

 above the Wapiti sandstone being of the age of marine beds at the top 

 of the Edmonton is very much less than that they are marine 

 beds earlier than the Edmonton. Beds in the vicinity of Lesser 

 Slave lake hitherto referred to the Laramie may also belong to the 

 top of the Belly River. 



UPPER PIERRE. 



The deposits of this division are in the main of marine origin. 

 The western margin of the Pierre sea early in the history of this 

 marine invasion, received great masses of detritus from the newly 

 elevated portions of the land area. Following the partial retirement 

 of the early Pierre sea there was another advance (see Plate VII) 

 which appears to have been of long duration judging by the thick- 

 ness of the fine-grained material deposited. This over a considerable 

 portion of Alberta amounts to nearly 900 feet of grey and dark grey 

 clay shales. The fossils found are of similar types to those of the lower 

 member, the Claggett. In Montana it is called the Bearpaw shale. 

 The name is generally retained in Alberta instead of the Pierre- Foxhill ; 

 but for Saskatchewan there is a possibility (in well-sections especially) 

 that the two divisions of the Pierre may not be recognized owing to 

 the lack of shallow-water deposits which elsewhere separate them. 

 The use of the term Bearpaw which is distinctive may find favour 

 for distinguishing these shales throughout Alberta. They are well 

 exposed on either side of the broad anticline which shows exposures of 

 Belly River rocks in southern Alberta. The margin of this sea was 

 well within the foothills of the country near the 49th parallel; but 

 within the present mountains it is not thought that any of the deposits 



