GLACIERS AND LAKES 249 



suit of glacial obstruction. Most of the lakes in the north- 

 ern states result from irregularities in the surface of the 

 drift deposited by the ice sheets. Minnesota and Wisconsin 

 are dotted with lakes of this type. 



There is still another kind of lake which is glacier-formed. 

 When the ice of a glacier is thickly covered with earth and 

 stone as are parts of the Malaspina glacier in Alaska, 



FIG. 132. LAKE LOUISE, A GLACIAL LAKE 



There are no lakes more beautiful than glacier lakes. 1. Name two 

 ways in which their basins have been prepared by glacial action. 2. What 

 is the source of their water? 3. Why is the water that enters them often 

 muddy? 4. Why is the outflow clear? 



upon which forests are growing, the covering prevents 

 melting in that portion of the glacier. During the melting 

 of the rest of the glacier, deposits are made around the 

 unmelted area. After a long time, it too is melted and 



