Review and Comment. 
351 
“Numerous boulders are to be seen lying on the glacier bed 
of crystalline rock. Some of these are rounded, some sub- 
angular. The ice flows around them without stirring them. 
Even the boulders resting on the loose, soft morainic material 
over which the glacier is advancing are able to channel the 
ice as it moves over them. 
“No blocks were seen in the act of being torn up from the 
subjacent rock, nor were loose stones being picked up. 
“A large rounded boulder was being rolled along under the 
ice, not shoved, at the same time it was being crushed. 
“A tongue of ice (about a cu. yd.) hanging from the roof 
of an ice cavern was seen pressing against a boulder that a 
man could have moved. The stone was not moved, and the ice 
was bent back in a curve (nearly a right angle). Scratched 
stones were rarely seen among those falling from the bottom of 
the glacier and in many places the rocks were scarcely if at all 
scratched. Although occasionally highly polished, the subjacent 
rocks even where scratched, showed genenally surfaces rough¬ 
ened by weathering or with only the angles removed. 
“ The upper layers of ice were seen to bend and flow over the 
lower wherever low barriers were met with in place of the 
lower strata being pushed up by an oblique thrust. 
“A glacier was advancing into a morainic lake, and in part 
against the terminal barrier. In place of ploughing up the 
obstruction, the ice was forced up into an anticlinal, along the 
axis of which was a fracture and a fault. 
“At several places where glaciers are advancing over mor¬ 
aines, they are leveling them and not plowing them out. 
This leveling process is by the dripping of the water from the 
whole under surface. 
“The fall of a great ice avalanche from a high snow held, 
down a precipice of a thousand feet, to the top of a glacier 
remainie was seen. These failing masses bring down frost- 
loosened stones from the sides of the mountains, upon the 
glacier. . . It is this material which furnishes mud to the sub¬ 
glacial streams, and not the rocky bed of the valley, worn 
down by glacial erosion. 
“One does not find that the glaciers, per se, are producing 
rock hummocks. These are the results of atmospheric agencies 
and aqueous erosion. They are only polished and scratched 
by the ice. 
“The effects of glaciation in removing angles and in polish¬ 
ing surfaces is small compared with atmospheric erosion upon 
the same rocks.'’ 25 
This is a most interesting series of observations. It must 
be borne in mind, however, that they were made at or near the 
ends of the glaciers, where the ice is yielding to the forces 
25 A. A. A. Sci., vol. 36, pp. 218-220. 
