Glacial Erosion in Norway. 221 
like a fluid. The energy upon the boulder was sufficient to crush 
it into one large and two smaller masses, together with stone dust. 
When seen, the three fragments had hardly begun to part company. 
The abrasion of the solid rock by the fall of stones, and detached 
masses of ice and stones, was illustrated at the locality just named. 
The two guides and myself succeeded in detaching a large boulder 
of about five tons weight, adjacent to the edge of the glacier. It 
went rolling and sliding down a hundred feet or more, tearing 
away great blocks of ice which held a considerable amount of 
debris, and in its wake, the rock was more or less crushed or 
scratched. 
Fic; 3—At Tunsbe 
z rgdalsbræen, d, a loose boulder, resting on rock a, in cavern ¢, 
against which a tongue q, of the moving glacies b, impiges and is bent backward. 
A further example of the ability of the ice to flow like a plastic 
body was shown in a cavern (Fig. 3c) 400 feet higher than the 
end of the glacier, where the temperature was 4°C., while that out- | 
side was 13°C, Upon the debris of the floor rested a rounded 
boulder (d) whose longer diameter measured thirty inches, A 
tongue of ice (q), in size more than a cubic yard, was hanging from 
the roof, and pressing against the stone. In place of pushing the 
‘Stone along or flowing around it, the lower layer of ice above the 
tongue had yielded, and was bent backward as easily and gracefully 
pea had been a thin sheet of lead, instead of one of ice a foot 
ick. 
According to the experiments of “Herr Pfaff,’ the temperature of 
1 Nature, Aug. 19, 1875. 
