102 COLEMAN ON THE GEOGEAPHY 



Rocks Observed. — At McCulloch aud French Cr^ks, green, finely A¥rinkled schists 

 occur, containing, especially toward the head of the former creek, auriferous quartz 

 veins, which may be looked on as the source of the gold of the placers. Boulders of, 

 grey granite and gneiss found along the creeks originate higher up the valley or at the 

 watershed, though none were seen in situ by the writer. Similar boulders, some of 

 porphyritic granite, are found on the trail between Laporte and Eevelstoke and come 

 probably from higher parts near the axis of the range. 



Rivers of the Selkirhs. — The streams flowing west out of the Selkirks are larger as a 

 rule than those flowing east, a fact accounted for, perhaps, by the greater rainfall on the 

 slope toward the Pacific, enabling the rivers fed by it to excavate their supply basins 

 more rapidly than those on the other slope, aud thus to shift the watershed slowly east- 

 ward of the centre of the range. At Donald, where the Canadian Pacific Railway crosses 

 the Columbia for the first time, the level of the river is 2,500 feet above the sea; but at 

 Eevelstoke, the second crossing, it is only 1,625— a difference of nearly 900 feet. The 

 streams flowing westward from the Selkirks must therefore have on the average a steeper 

 slope, which no doubt acts in the same way as the increased rainfall in hastening the 

 excavation of their valleys. 



Glaciers of the Selkirks. — Perhaps in no part of the world are glaciers more numerous 

 than on this range and the mountains northward toward Alaska and the Arctic Ocean. 

 From many summits of the range, dozens of them may be seen of all sizes from tiny ones 

 with a few acres of neve ending in a tongue of ice, to masses of snow and ice several miles 

 across and covering many square miles of surface. There is evidence showing retrogres- 

 sion of the ice in some cases. Cirques are common just below snow level, and are due 

 perhaps to the erosive power of former glaciers, though it does not seem impossible that 

 they may have been excavated by converging streams. A number of glaciers examined 

 by the writer show signs of recent retrogression in the bareness of the rock of the valley 

 just below the front of the glacier. There appears not to have been time since the with- 

 drawal of the ice for lichens, mosses and other plants to form even the beginning of a 

 bed of soil. A retrogression o'f the glaciers does not necessarily imply a rise in the 

 annual temperature, since a diminished snow-fall resulting from a change in prevailing- 

 winds would have the same effect. 



Difficulties of Exploration. — Every one who has attempted exploration in the Selkirks 

 will agree that few mountain ranges ofler so many obstacles to the explorer and the 

 geologist. The moist and comparatively nrild climate causes an immense growth of 

 forest aud underbrush, much greater than that of the Rockies, for instance, so that up 

 to about 7,000 feet' the rock is largely hidden by vegetation, except along the water- 

 courses. Unclothed precipices are miich more common, according to the experience of 

 the writer, in the Rocky Mou tains, perhaps because, from their later origin, they have not 

 suffered so much from erosion. Their drier climate must work in the same direction of 

 limiting erosion. 



Travel through the forests of the Selkirks is A'ery laborious. In most cases all 

 necessaries must be carried on the back— no light matter when a trip of two weeks is 

 undertaken, up steep inclines, through second-growth evergreens so thickly planted that 



' The tree line is at 6,700 feet on Surprise Mount, and about 7,300 on the southern side of Lookout Point. 



