GLACIERS. 



691 



will move over a horizontal surface, provided the supply of material is 

 constant and sufficiently great. There are cataracts and cascades among 

 them, as well as among rivers. One of the large tributaries of the 

 Mer de Glace, the Glacier du Geant {g, Fig. 1100), descends in an 

 immense ice-cascade from the plateau of the Col du Geant, over a ver- 

 tical rock wall of the Tacul, into the valley below, making a plunge 

 of 140 feet. The Glacier of the Rhone — one of the grandest in the 

 Alps — is another ice-cataract. As the glacier commences its steep 

 descent, it becomes broken across ; and thus great sections of it plunge 

 on in succession, separated partly by profound traverse chasms. Fig. 



Fig. 1105. 



The Gorner Glacier. 



1103 gives the outline of the lower part of the glacier, am being the 

 cataract, mb, its terminal portion or foot, from the extremity of which 

 the river Rhone issues, and c, c, c, transverse crevasses of the cascade. 

 The same is shown in profile in Fig. 1104, in which c, c, c are the 

 transverse crevasses. 



The smaller and shorter valleys of the Alps, have also their accu- 

 mulations of ice which break loose and at intervals descend the steep 

 slopes or precipices, perhaps thousands of feet, in crashing avalanches, 

 in which the ice is broken to fragments. 



