114 GLACIERS 



the atmosphere. In the Alps, where the glaciers flow in deep 

 ravines, the moraines are large, and some of the great Alaskan 

 glaciers have their lower reaches so covered with rubbish, that 

 the ice is visible only in the crevasses. In Greenland, on the 

 contrary, the inland ice-cap has very little material on its surface, 

 because only scattered nunataks rise above it. 





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FlG. 41. — Front of Bowdoin Glacier, Greenland. The dark bands are made by 

 englacial drift. 



The substances frozen into the bottom of the glacier and pushed 

 along over its bed form the ground moraine, and at the end of the 

 glacier is the terminal moraine (see Fig. 57), where all the mate- 

 rials carried are dumped in a promiscuous heap, except so much 

 as is swept away by the stream of water. Besides the moraines 

 proper, there is a certain amount of englacial drift, carried in the 

 body of the ice. This is derived from debris that comes from the 

 surface, but does not work its way entirely to the bottom, as well 



