GEOLOGICAL AREAS OF CANADA. 19 



fronting abruptly on the east, and strong westerly clip towards the 

 central part or axis of the chain. Gneissoid I'ocks and crystalline 

 schists — which make up the main mass of the Rocky Mountains in 

 Hew Mexico and Coloiado, and which occur also immediately west 

 of the chain in British Columbia — appear to be altogether wanting 

 in these eastern ranges. Finally, it may be pointed out, as a char- 

 acteristic feature of the district, that, along the base and gorges 

 of the mountains, terraced accumulations of gravel and limestone- 

 shingle are seen at varying elevations ; and in many cases these 

 shingle terraces or beaches extend along the river-valleys far into 

 the prairie region to the east. 



PEOVINCE OF BRITISH COLUMBIA. 



This Province— extending westward from the boundary-line of the 

 North-West Territories in the Rocky Mountains, to the Pacific coast 

 and outlying islands — admits of a convenient and more or less natural 

 subdivision into four areas. These may be named as follows : — 

 (1) The Eastern Mountain District; (2) The District of the Central 

 Table-land ; (3) The Coast and Western Mountain District ; and 

 (4) The Island District. 



(1.) The Eastern Mountain District. — This includes the western 

 ranges of the Rocky Mountains proper, and the adjacent ranges of 

 the Selkirk, Gold, and Cariboo Mountains. Physically, it consists 

 of a number of roughly-parallel chains, running in a general north- 

 west direction, and presenting an average elevation of from 8,000 to 

 10,000 feet above the sea, with many isolated points of greater 

 altitude. Among the latter, some of the more striking in the main 

 chain include Mount Sabine, Mt. Forbes (13,460 ft. ?), Mt. Balfour 

 (14,431 ft. 1), Mt. Murchison (16,000 ft. f), Mt. Hooker (15,700 ft. V), 

 and Mt. Brown (15,990 ft. 1) Several points in the Selkirk Moun- 

 tains also exceed 12,000 feet; and glaciers occur in the higher 

 valleys or gorges of both chains. Tilted and contorted strata of 

 limestone and sandstone, apparently for the greater part of Devonian 

 and Carboniferous age, occur on the western as on the eastern slopes 

 of the Rocky Mountains proper, and terraced accumulations of gravel 

 and limestone-shingle are seen at various elevations. The Selkirk, 

 Gold, and Carriboo ranges, which are only separated from the western 

 flanks of the central mountains by comparatively narrow valleys, 

 appear, on the other hand, to consist largely of talcose and micaceous 



