110 



Sierra Club Bulletin. 



Glacier gives rise to a very perfect medial moraine, about 

 one third the glacier's width from its western edge. A 

 high bluff of lava just below the junction of the Stevens 

 furnishes material for a heavy lateral moraine on the 

 western side also, leaving but a narrow strip of clear ice 

 between it and the medial. The medial moraine in the 

 upper reaches of the glacier is a mere train of debris on 

 the surface. Lower down it forms a ridge, and about a 

 thousand feet back from the snout this ridge is over 

 eighty feet high. Nowhere, however, does the skin of 

 debris average more than six inches to a foot in thick- 

 ness, the core of the ridge being clear ice, which is 

 protected from more rapid melting by the covering. 



The motion of the glacier was measured accurately at 

 a point about 3,000 feet from the snout. Here the sur- 

 face was smooth and free from crevasses, and the sides 

 of the stream almost parallel. A white stake about two 

 inches square was set in a pile of rocks on top of one 

 of the ancient border moraines on the east side, 300 feet 

 from the eastern edge of the glacier, and about fifty 

 feet above its surface. This will for convenience be called 

 the East Base. A second stake, the West Base, was set 

 on the opposite bank on a ledge of granite about the same 

 height above the surface. These stakes were intervisible, 

 and the distance between them as determined by triangu- 

 lation was 1,944 feet. A transit-instrument was set over 

 the East Base, sighted on the western one, and a line 

 run across the glacier. 



The usual method of observing the motion of a glacier 

 is to measure the movement of rods placed in holes bored 

 in the ice. In the present instance, owing to inexperi- 

 ence, and to the difficulty of transportation, the auger 

 used for boring the holes was but fourteen inches long, 

 and it was found that a wooden rod placed in so shallow 

 a hole was almost certain to fall over in the course of 

 a day, on account of the rapid melting at the point of 

 contact between the rod and the ice. As a consequence 

 no rods were placed in the holes at all, but these latter 



