GLACIERS IN SWITZERLAND. 167 



and grooved, and the grooves are in the longitudinal direction 

 of the valley. 



Now, by the character of this polished surface, by the uniform 

 direction of those furrows, you can determine the course which 

 the mass of ice has taken ; and this is one of the signs by which 

 you can recognize the former presence of glaciers, where they 

 no longer exist ; and that they have extended beyond their 

 present limit in times wlien the surface of the earth had other 

 climatic conditions from those now prevailing in the same 

 localities, is demonstrated by the fact that at the lower end 

 of the glaciers of Switzerland you see these same materials in 

 the bottom of valleys no longer covered by glaciers. You see 

 below them, wherever they are removed, the bottom and sides 

 of the valley polished, scratched and grooved in the same man- 

 ner as under the glaciers ; so that you can ascertain, with per- 

 fect certainty, from the continuity of these marks, how far the 

 glaciers did extend. Tliat this is the same agency, and that 

 you cannot ascribe what is beyond the glacier to any other 

 cause than the action of the glacier, is proved by the continuity 

 of the phenomena. I have examined the surface under gla- 

 ciers ; I have repeatedly penetrated under them, following the 

 lines which the water oozing from their extremity produced. I 

 have frequently descended through crevasses into the sides of 

 the glacier, and ascertained by my own eyes how this polishing 

 and grinding are produced. 1 have seen occasionally, in the 

 morning, the powder which resulted from the grinding of this 

 machinery still remaining in the groove which had been made 

 during the last twelve hours ; so that about the fact of the 

 glacier being capable of producing this result there can be no 

 doubt. And I have sought everywhere, by the seaside and in 

 water-courses, for similar appearances, and failed to find them 

 anywhere ; so that I am prepared to affirm, in the most em- 

 phatic manner, that water will not produce the same results 

 that ice will. 



But that is not the only sign by which we can recognize the 

 glacier. On the surface of the ice there is accumulating, at 

 some points, a larger amount of the loose materials than is pass-, 

 ing under the surface of the ice, and walls five, ten and some- 

 times twenty feet in height accumulate upon sides of the glacier, 

 and they are carried forward, perhaps more slowly than the 



