ROCKS ON THE SOUTH BRANCH. 



385 



of sandstone twelve feet from the river level is capped 

 by brown and red argillaceous layers, forty feet thick 

 in the aggregate. Drift sand, ten feet thick to the prairie 

 level, succeeds. The upper portion of the drift is hard 

 and reddish coloured ; as it approaches the clays below, it 

 partakes of an argillaceous character. The upper stratum 

 of the sandstone weathers reddish brown, with bands of 

 deep red and purple. Below this a greenish-grey stratum 

 occurs enveloping concretions of a reddish-brown colour. 

 The concretions are hard and argillaceous. The greenish- 

 grey matrix is soft when weathered, otherwise hard, and 

 may be split without difficulty into thin layers. The con- 

 cretions occur in the sandstone in forms easily detached, 

 and often contain abundance of Avicula Linguceformis. 

 If the clays above the sandstone are rock in position, the 

 exposure has an altitude of about sixty feet. Fragments of 

 fibrous lignite, dark-brown and sometimes approaching to 

 black in colour, occur in the sandstone. The attitude of 

 the rocks is nearly horizontal, and the greenish-grey sand- 

 stone is identical with the formation seen on the south 

 bend of the Qu'appelle above Sand Hill Lake ; the red 

 layers are similar lithologically to those observed at the 

 height of land in the same valley, holding the same 

 species of shells. Sometimes layers of grey sandstone 

 occur which are easily split ; they contain the impressions 

 and remains of plants. The position of these rocks is 

 about forty-five miles from the Qu'appelle valley. 



The river banks and the whole country is now much 

 lower ; this subsidence began about four miles south of 

 our camp. The banks at our second camp are not more 

 than 100 feet in altitude, and are becoming lower as 

 we proceed north. They are treeless areas, and so is 

 the prairie on either side, with few detached exceptions. 



vol. i. c c 



