Page:Popular Science Monthly Volume 14.djvu/100

90 The rising glories of the new era far outshine the splendors of the past.



OME months ago we described very rapidly the principal features of that widely-extended and enigmatical formation known as the Drift, and in conclusion indicated an intention to consider the views of geologists as to its cause, and in particular illustrate the paramount claims to our acceptance of the so-called Glacial Theory. In this paper those hypotheses are given, accompanied by a proof of the manifest power of existing ice-streams, thus offering the most striking argument for their colossal potency in times when their size and duration were factors in their influence, fully commensurate with the continental ravages we attribute to them.

A great variety of theories have been submitted to the world as possible explanations of the appearances we have reviewed, and, though we cannot occupy ourselves with their discussion, it may be interesting, from their singularity and number, to enumerate such as have arisen.

First is the theory of Deluc, who supposed the erratics to have been thrown upward in the air by the same force that elevated the mountains, and that in their promiscuous descent they rolled and tumbled everywhere.

Second in order is the hypothesis of De Buch and Escher, who imagined that an immense deluge swept the bowlders along its surging course, and landed these blocks upon the acclivities of mountains, through the stupendous impetus they had acquired in its midst. 