56 



ICE DEPOSITS 



ledge can be discovered, it is easy to determine the distance to 

 which they have been carried. Sometimes a great boulder is 

 lowered so gradually and gently by the retreating ice, that it is 

 exactly balanced, and may be moved backward and forward by the 

 hand. This is a " rocking-stone," though it must not be supposed 

 that all rocking-stones are glacial. (See p. 86.) 



The water deposits which are made in the neighbourhood of and 

 in association with a glacier, are also characteristic and should be 



Fig. 60. — River issuing from the Malaspina Glacier, Alaska. (U. S. G. S.) 



noticed in this connection. Very instructive examples of this 

 combined action may be observed about the great Malaspina 

 glacier in Alaska. This is an immense ice-sheet, with an area 

 of 1500 square miles, which is formed at the foot of the St. 

 Elias Alps by the confluence of several great glaciers. All the 

 outer borders of the glacier are covered with sheets of moraine 

 matter, and upon the stagnant portion of this is a luxuriant growth 

 of bushes, beneath which is a thickness of not less than 1000 feet 



