A Dolerite Sheet. 
72 
H. T. FERRAll. 
On the north wall of the North Fork, three glaciers drain out of one firnfield 
and end about 1000 feet above the ice of the main valley (Fig. 39). Two of these are 
cliff-glaciers, for the ice breaks off at the edge of a cliff and falls in avalanches 
which are lost in the main glacier at the foot of the cliff. The third has lately 
been a cliff-glacier, but its present loss by ablation exceeds the supply, and it now 
ends some distance from the edge of the cliff and therefore is of Alpine type. The 
south side of the Upper Kukri Hills has a numerous series of hanging valleys 
distributed at regular intervals between D and D 4 . There are at least eight in a 
The Obelisk C 3 
Fig. 39. — Three Ice-tongues falling into North Fork. 
distance of 10 miles. Of the eight between D and D 4 , five have glaciers of Alpine 
type which, keeping their continuity, fall as cascades into the main valley below, and 
give rise to little or no disturbance in the latter. 
7. Cliff-glaciers. 
The three other glaciers between D and D 4 are true Cliff-glaciers and, ending some 
700 or 800 feet above the main glacier, discharge only as avalanches down the face of 
the cliff. The width of these glaciers is usually less than a quarter of a mile. They 
extend most of the way down the cliff, which is here about 4000 feet high. The 
