TRANSPORTATION OF ROCKS BY ICEBERGS 



141 



From time to time the polar bear is thus conv^eyecl from 

 Greenland to Iceland, on which island it is not indifrenous. 

 The people of this Arctic realm are compelled to exterminate 

 the invaders lest they should destroy their cattle and ravage 

 their fields. 



As the icebergs are derived from glaciers, they commonly 



Showing small glaciers and floating icebergs. In the foreground are masses of rock dropped from float- 

 ing ice. 



carry a great deal of rocky matter torn from the surface over 

 which they have found their way. The bottom portion of any 

 thick glacier is commonly filled, sometimes to the depth of a 

 hundred feet or more, with this fractured stone, varying in size 

 from grains of mud or sand to blocks the size of a small house. 

 When the icebergs float away from the land they bear the 

 mass of debris with them on their journey, it may be for a 



