262 EDWARD M. BURWASH 



over 1, 800 feet. Many of them are hanging valleys as regards the 

 Cheakamous valley. They exhibit well-marked evidences of the 

 second epoch of glaciation, which was merely an extension of the 

 existing glaciers which filled the valley-system, including the main 

 valleys, but did not override the range in a continuous icesheet. 



II. VULCANISM 



Superimposed upon the topographic featues which have been 

 described are the andesitic cones and lava flows, which are unglaci- 

 ated by the earlier icesheet, and only partially so by the later ice- 

 advance. The volcanic foci which have been visited up to the 

 present are three in number, but other peaks visible to the north- 

 ward seem to be undoubtedly of similar origin. 



Mount Garibaldi, the largest of the group and also the most 

 southerly, is the highest peak in the region. Its summit is 8,700 

 feet above the sea, from which it is about 12 miles distant. It 

 stands about 3,500 feet above the plateau. It is so surrounded by 

 glaciers and snowiields that a study of its relations to the under- 

 lying terranes is impracticable, except possibly on the western face 

 where freshly-cut ravines may expose sections. The walls of the 

 cirques which have been cut into its sides afford admirable sections 

 of the cone itself. The materials of which it is composed are of a 

 light reddish-brown color, and appear to be largely fragmental. 

 Lava streams extended down into the inner Cheakamous valley, 

 where remnants of them may be seen along the Lilooet road. The 

 proximity of the cone to the valley and the somewhat loosely 

 coherent nature of the materials of which it is composed have 

 rendered dissection somewhat rapid, and the conical symmetry has 

 already been lost to a considerable extent, while the crater can only 

 be doubtfully identified. 



Situated about 5 miles to the north of Garibaldi, on the western 

 margin of the lake of the same name, is the double volcanic cone 

 known as Red Mountain, which has an elevation of about 1,000 

 feet above the plateau, or 6,500 feet above sea-level. As this 

 volcano is much more easily accessible than Garibaldi, and practi- 

 cally free from snow, a fairly complete view was obtained of it. 

 The volcanic cone stands within a cirquehke basin cut into the 



