G. M. Dawson — Geology of British Columbia. 157 



attracted little attention till the discovery of gold in 1858. As 

 among the first in the field geologically may be mentioned Dr. 

 Hector and Messrs. H. Bauerman and G. Gibbs. The observations 

 of these gentlemen, though bringing to light many facts of interest, 

 were confined to a comparatively small part of the area of the 

 province, and it was not till the inclusion of British Columbia in the 

 Dominion of Canada in 1871 that the systematic operations of the 

 Geological Survey of Canada were extended to this region. Since 

 this date a number of reports treating of the geology of British 

 Columbia have been published, and on these, together with a per- 

 sonal knowledge of the country, obtained during five seasons' work 

 in it in connexion with the Survey, I shall chiefly depend in giving 

 a brief account of the main geological features so far developed. 



British Columbia includes the whole breadth of a portion of the 

 great Cordillera belt which forms the Pacific margin of the Con- 

 tinent. This here consists of four parallel mountain ranges running 

 in general north-westerly and south-easterly bearings, which, be- 

 ginning on the Pacific Margin, may be named as follows : — Van- 

 couver Eange, Coast or Cascade Range, Gold Eange, and Rocky 

 Mountain Range proper, the last constituting the western border of 

 the great plains of the interior of the Continent. 



The first mentioned, in a partially submerged condition, forms 

 Vancouver and the Queen Charlotte Islands, and still rears some of 

 its peaks to a height surpassing 6000 feet. The valley lying to the 

 north-east of this is occupied by the sea, forming the Strait of 

 Georgia, Queen Charlotte Sound, and Hecate Straits. The Coast 

 Range is a rugged mountainous district with a width of about one 

 hundred miles, and axial summits reaching in some places elevations 

 surpassing 8000 feet. To the north-east of this stretches a region 

 which may be called the Interior Plateau of British Columbia, the 

 average width of which is nearly one hundred miles, and its mean 

 elevation about 3500 feet. This plateau is, however, irregular, 

 hilly, or even in some places mountainous, and is intersected by 

 deep trough-like river valleys. It is only when it is occupied by 

 Tertiary volcanic rocks that it assumes considerable uniformity of 

 surface. 



Bounding the plateau to the north-east is a third wide range, 

 known locally as the Cariboo, Columbia and Purcell Mountains. 

 It is broken to the north at the 54th parallel and resumes imder the 

 66th as the Omineca Mountains. This mountain axis may be named 

 the Gold Range, and it is probable that many summits in it surpass 

 8000 feet. Separated from it by a narrow but well-defined valley is 

 the Rocky Mountain Range with an average width of fifty to sixty 

 miles. This shows peaks of about 10,000 feet in height on the 4:9th 

 parallel, is supposed to surpass 15,000 feet near the 52nd, and 

 becomes comparatively low and narrow in the vicinity of the Peace 

 River, about the 56th parallel. 



Such are the main orographical features of British Columbia, a 

 slight knowledge of which is necessary to render intelligible the 

 description of its geological structure. 



