GLACIERS 



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gether forms a layer of dirt and rocks along the middle of 

 the larger glacier. At the end of the glacier this mate- 

 rial which it has borne along is deposited in irregular 

 piles of rocks and dirt. 



The accumulations of debris along the sides are called 

 lateral moraines, those in the middle, medial moraines, and 

 those at the end, terminal moraines. Great bowlders may 



THE DANA GLACIER IN THE HIGH SIERRAS. 



be carried along on the ice for long distances without the 

 edges being worn, since they are carried bodily and not 

 rolled as in streams. 



On the under surface of the glacier, rocks are dragged 

 along firmly frozen into the ice. The weight of the gla- 

 cier above presses them with tremendous force upon the sur- 

 face over which the glacier passes. In this way scratches 

 or grooves are made in the bed rock underlying the gla- 



