PLEISTOCENE VULCANISM OF THE COAST RANGE 

 OF BRITISH COLUMBIA 



EDWARD M. BURWASH 

 Upper Canada College, Toronto 



During the present summer the writer had occasion to visit the 

 Mount Garibaldi region of the Coast Range of British Columbia, 

 which lies about forty miles due north of the city of Vancouver, 

 between 49°4o' and 50° north latitude and on the 123d meridian of 

 west longitude. The approach to this district is by way of Howe 

 Sound, a typical fiord, and the valley of the Cheakamous River. 

 The volcanic origin of Mount Garibaldi, the highest peak in the 

 region, had been recognized by members of the British Columbia 

 Mountaineering Club, who made the first ascent of it some six or 

 seven years ago. The region to the north of Garibaldi as far as the 

 Black Tusk Mountain was subsequently penetrated for the first 

 time by Mr. W. J. Gray, in whose company the present writer had 

 the advantage of visiting the locality. The general situation, as 

 far as it could be determined in a few days' study, is as follows: 



I. PHYSIOGRAPHIC AND GLACIAL HISTORY 



The Cheakamous River flows into the head of Howe Sound 

 through a valley whose general trend is the continuation of that 

 of the sound itself and lies in a north-northeast direction. The 

 mountain-mass known as the Garibaldi Range lies to the eastward 

 of it. At a point about twenty-five miles from tidewater the 

 Cheakamous receives on the eastern side a tributary which is known 

 as Stony Creek whose valley affords a convenient means of access 

 to the higher parts of the range. Commencing with the bottom of 

 the Cheakamous valley, the following features are to be observed 

 as one ascends the range: 



I. Post-Glacial gorge, in which the Cheakamous at present flows, 

 cut through glacial deposits and in part through the rock to a depth 

 of at least 300 feet. 



260 



