GEOGRAPHY 259 



valleys ' they have been called. Above the cliffs of the 

 gorges the mountains rise by gentle slopes to the base of 

 the peaks. The cross profile of each gorge and its sur- 

 roundings is that of ice, not of water carving. It is the 

 work of channel erosion, not of valley erosion, and the 

 channels were filled with ice. It is a colossal exhibition 

 of the eroding power of water in solid form. From Lynn 

 Canal, a fiord ninety miles in length, there have been car- 

 ried off and dumped into the Pacific more than 200 cubic 

 miles of rock, and from all the fiords of southeastern Alaska 

 the amount removed may be safely estimated at thousands 

 of cubic miles. The ice has but recently retreated from 

 these gorges, for since its retreat water has done but little 

 work, although the region is one of heavy rainfall and ex- 

 tremely steep slopes, where aqueous erosion is at a maxi- 

 mum. 



Of the great glaciers which occupied this region a short 

 time ago, only trifling fragments remain in the upper ends 

 of the gorges, and comparatively few now reach the sea. 

 I use the word trifling, however, merely in relation to their 

 former extent, for absolutely these remnants are not at 

 all trifling. The ice cap of Greenland and the glaciers 

 of the Antarctic continent alone exceed them in magni- 

 tude. All the glaciers of Switzerland together would 

 form but a few rivulets of ice on the surface of the great 

 Muir Glacier, and the Muir is but one of many glaciers 

 of equal magnitude. Indeed, on this coast are scores of 

 live glaciers, glaciers which reach the sea, presenting to 

 it fronts of ice or ice walls rising from the sea bottom to 

 200 or 300 feet above its surface, and several miles in 

 length, and which drop bergs, with thundering sound, 

 into the sea. Of such glaciers about thirty were visited 

 by the Harriman Expedition, and others are known. Of 

 dead glaciers, or those whose fronts do not reach the sea, 

 hundreds are known. 



