TRANSPORTATION OF DEBRIS 



155 



Fig. 156. End of a North Greenland glacier, showing the upturning of the 

 layers of ia- at the end. This structure is common in North Greenland. At one 

 point, a few stones ar-j seen on the surface of the ice where an upturned layer comes 

 to tlu' 



glacier, basal and englacial debris are carried to the surface by actual 

 upward movement, and a terminal moraine or a series of terminal 

 moraines may be developed where the upturned layers of ice outcrop 

 at the surface (Fig. 157). That the material of these moraines was 

 originally basal is shown in many cases by the bruised and scratched 



I-'ig. 157. Surface terminal moraines due to upturning. 

 North Greenland. 



of the ice-sheet, 



condition of the bowlders and pebbles, or by the nature of the mate- 

 rial itself. The upturning may affect the edges of glaciers (Fig. 158) 

 as well as their ends, and the material thus brought to the surface 

 gives rise to lateral moraines. In some cases, too, there is upturn- 

 ing of the ice along a longitudinal zone well back from the lateral 

 margins (Fig. 158), and the material brought to the surface in such 

 a zone gives rise to a medial moraine. This upturning of ice has 



