GLACIERS 205 
with the debris that the glacier is able to rasp from 
its bed. This loose rock material beneath the ice is 
called the ground moraine (Fig. 109). 
All the rock material is gradually carried toward the 
front of the ice, where melting cuts off further pro- 
gress. The stream that flows out trom the ice cave 
(Fig. 110) at the margin of the glacier, is able to 
bear away some of the finer fragments; but much 
cE ATi ae) AW 
Me poe" ANTS Wat 
Y, ee nN AR OS 
@ Ud ff N \ : ‘ 
SIL hia sa iid ol A ‘ ‘ 
Fie. 109. 
Diagram to illustrate position of ground moraine G. Also shows medial moraine 
M, crevasse C, and terminal moraine J 
of the burden accumulates at the front end, forming 
a fourth moraine, the frontal or terminal moraine 
(Figs. 108, 109, and 111). 
These various moraines are all made of irregularly 
arranged rock fragments, of various kinds and sizes, 
transported from the several parts of the glacier valley. 
Not only is there a complexity of material in the 
moraine, but the form is also irregular and confused. 
The hills and hillocks are hummocky in the extreme. 
