The glaciers are local in character, and comparatively few in number; they are confined to valleys having some general slope downward. The whole Alpine mass does not move down upon the plain. The movement downward is limited to these glacier-rivers.
The glacier complies with some of the conditions of the problem. We can suppose it capable of taking in its giant paw a mass of rock, and using it as a graver to carve deep grooves in the rock below it; and we can see in it a great agency for breaking up rocks and carrying the detritus down upon the plains. But here the resemblance ends.
That high authority upon this subject, James Geikie, says:
“But we can not fail to remark that, although scratched and polished stones occur not infrequently in the frontal moraines of Alpine glaciers, yet at the same time these moraines do not at all resemble till. The moraine consists for the most part of a confused heap of rough angular stones and blocks, and loose sand and débris; scratched
stones are decidedly in the minority, and indeed a close search will often fail to show them. Clearly, then, the till is not of the nature of a terminal moraine. Each stone in the ‘till’ gives evidence of having been subjected to a grinding process. . . .
“We look in vain, however, among the glaciers of the Alps for such a deposit. The scratched stones we may occasionally find, but where is the clay? . . . It is clear that the conditions for the gathering of a stony clay like the I till’ do not obtain (as far as we know) among the Alpine glaciers. There is too much water circulating below the ice there to allow any considerable thickness of such a deposit to accumulate."
But it is questionable whether the glaciers do press with a steady force upon the rocks beneath so as to score them. As a rule, the base of the glacier is full of water; rivers flow from under them. The opposite picture, from Professor Winchell’s “Sketches of Creation,” page 223, does not represent a mass of ice, bugging the rocks, holding in its grasp great gravers of stone with which to cut the face of the rocks into deep grooves, and to deposit an even coating of rounded stones and clay over the face of the earth.
On the contrary, here are only angular masses of rock, and a stream which would certainly wash away any clay which might be formed.
Let Mr. Dawkins state the case:
“The hypothesis upon which the southern extension is founded—that the bowlder-clays have been formed by ice melting on the land—is open to this objection, that no similar clays have been proved to have been so formed, either in the Arctic regions, where the ice-sheet has retreated, or in the districts forsaken by the glaciers in the Alps or Pyrenees, or in any other mountain-chain. . . .
The English bowlder-clays, as a whole, differ from