200 ELEMENTARY GEOLOGY 
something like wax or pitch; and as it continues to 
move, seeks the lowest ground, just as water does. 
So by this means an ice stream is formed, which con- 
tinues to flow either until it meets the sea, or more 
commonly, extends far enough below the snow-line* 
Sos 
Fire. 105. 
Terminus of the Robertson glacier, North Greenland, showing stream flowing 
from ice front. 
(Fig. 105) to reach the pomt where the warmth of the 
sun and air can melt it. From this place, which is 
the front of the glacier, there flows a stream which is 
furnished with water by the melting ice (Fig. 105 and 
1 The snow-line is the line of permanent snow, as for instance on a moun- 
tain top, where it always stands. 
