MOUNT RAINIER 



of a formerly long spur dividing the original cavity, 

 is fast being eliminated by the undermining process, 

 so that in time the head wall will describe a smooth, 

 uninterrupted horseshoe curve. 



In its headward growth the Carbon Glacier, as one 

 may readily observe on the map, has encroached con- 

 siderably upon the summit platform of the mountain, 

 the massive northwest portion of the crater rim of which 

 Liberty Cap is the highest point. In so doing it has 

 made great inroads upon the neve fields that send down 

 the avalanches, and has reduced this source of supply. 

 On the other hand, by deploying laterally, the glacier 

 has succeeded in capturing part of the neves formerly 

 tributary to the ice fields to the west, and has made 



fx>d some of the losses due to its headward cutting, 

 ut, after all, these are events of relatively slight 

 importance in the glacier's career ; for like the lower 

 ice fields of the Nisqually, and like most glaciers on 

 the lower slopes of the mountain, the Carbon Glacier 

 is not wholly dependent upon the summit neves for 

 its supply of ice. The avalanches, imposing though 

 they are, contribute but a minor portion of its total 

 bulk. Most of its mass is derived directly from the 

 low hanging snow clouds, or is blown into the cirque by 

 eddying winds. How abundantly capable these agents 

 are to create large ice bodies at low altitudes is con- 

 vincingly demonstrated by the extensive neve fields 

 immediately west of the Carbon Glacier, for which the 

 name Russell Glacier has recently been proposed. It 

 is to be noted, however, that these ice fields lie spread 

 out on shelves fairly exposed to sun and wind. How 

 much better adapted for the accumulation of snow is 

 the Carbon Glacier's amphitheater ! Not only does 

 it constitute an admirably designed catchment basin 

 for wind-blown snow, but an effective conserver of the 

 neves collecting in it. Opening to the north only, its 

 encircling cliffs thoroughly shield the contained ice 

 mass from the sun. By its very form, moreover, it 



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