SECRETARY'S REPORT. 183 



When these loose materials which fall on the surface of the 

 glacier are, with its movement, bronght down to its lower end, 

 they accumulate at the point of its termination, and form at its 

 lower end a hill across the valley, in which the glacier termi- 

 nates. Now, these circumscribed hills of loose materials mark 

 the boundary of the glacier, and within that boundary the 

 whole surface of the rock underneath presents the character 

 I have described. But let us examine a little the sides of the 

 valley, above the present level of the glacier. ' We find that 

 they are polished like the rock underneath. They are polished 

 in the same way, and scratched and ground in the same way, as 

 if the glacier had had, at one time ti higher level ; and beyond 

 its present termination, in the same valley, I find there are 

 such concentric hills of loose materials. They are not arranged 

 a§ a river would arrange them. A river deposits such materials 

 in the centre of its course, but these are all arranged in concen- 

 tric moraines, across these valleys. Now, take this glacier of 

 which I have spoken, at the head of the valley of the Alps, ter- 

 minating near the Grimsel, where the hospice stands, which is 

 the stopping-place for travellers from the Bernese Oberland into 

 Italy. Now, the distance from the origin of this glacier in the 

 Alps to the chain of the Jura, is over a hundred miles, follow- 

 ing the sinuosities of tlie valley, and all over this tract, we find 

 these concentric moraines. That is, this glacier must once 

 have extended over eighty miles beyond the limits wh?ch it 

 occupies now. No doubt it ojice reached the Jura, for boulders 

 identical in character with those which we see dropped from 

 the summit of the Schreckhorner, — talc slate boulders, which 

 are unmistakable, and cannot be confounded with any other 

 rocks along the whole of this track, — will be found three thou- 

 sand feet above the level of the plain, on the crest of the Jura. 

 It would seem, then, as if the ice had once occupied all that 

 space. Let us look at the valley of the Aar. When you go 

 from the higher part of the plains of Switzerland into the Alps, 

 you have a deep cut, and there the level of the valley is about 

 two thousand eight hundred feet above the sea. On the sides 

 of this valley, you have these polished surfaces, to a height of 

 nine thousand feet. That gives you the thickness of the ice 

 there at about six thousand feet, when the glacier, whicli we 

 now know to be about one thousand feet thick, extended forty 



