18 GEOLOGICAL AREAS OP CANADA, 



and ttird prairie-steppes, rising in the east, above the line of elevation 

 between Pembina Mountain and tlie Basquia Hills to an altitude of 

 about 1,600 feet above the sea, and in its more western extension on 

 the third prairie (west of the Grand Coteau, Eagle Hills and Thick- 

 wood Hills) to from 2,000 to over 4,000 feet. It encloses many 

 sterile tracts, but over a large portion of its area the soil appears to 

 be of good fertility. Ranging west of the Pembina, Riding, Porcu- 

 pine, and Basquia Hills, it extends over the vast region ti-aversed 

 by the Qu'Appelle River, the Upper Assiniboine, north and south 

 branches of the Saskatchewan, and the upper course of the Artha- 

 basca, and rises gradually into the eastern slopes of the Rocky 

 Mountains. The eastern section — 'and probably the greater portion 

 of the entire district — is occupied by Cretaceous strata, consisting 

 mostly of sandstones and shaly clays in generally horizontal beds, 

 overlaid more or less by sands of G-lacial or Post-Grlacial age ; whilst 

 towards the west, but without any strongly-marked lines of demar- 

 cation, these Cretaceous strata are succeeded by Cainozoic deposits. 

 The latter consist chiefly of sandy clays, with associated beds of 

 lignite and ironstone. Lignite occurs also in the Cretaceous strata 

 of the district. In many of its beds, as in the Qu'Appelle valley 

 and southwards generally, it presents the usual woody or earthy 

 character, but on the Upper Saskatchewan and elsewhere, much of 

 it is of a comparatively dense compact quality, and closely resembles 

 ordinary bituminous coal. 



(4.) The Mountain District. — Includes the foot-hills and eastern 

 ranges of the Rocky Mountains, and extends westward to the 

 boundary-line of British Columbia. This eastern portion of the 

 Rocky Mountain chain enters the North-west Territory in the form 

 of several distinct ranges which curve towards the north-west, and 

 appear gradually to intermingle. Southwards, the mountains present 

 an average elevation of about 8,000 feet above the sea, with occasional 

 points of higher altitude ; but in their northern extension — as seen 

 in the transverse valley of the Peace River, and elsewhere towards 

 the Arctic Ocean — their altitude becomes greatly diminished. They 

 are composed essentially of dolomites, limestones, and sandstones, 

 apparently of Devonian, or of Devonian and Carboniferous age. 

 Probably, older Paleeozoic and more recent formations, will eventually 

 ;be found amongst them. In some few places their uplifted strata 

 still retain their origiaal horizontality, but as a rule they occur in 

 highly-tilted, broken, and contorted beds, with deeply escarped faces 



