WE, come now to the theory which is at present most generally
accepted:

It being apparent that glaciers were not adequate to produce the
results which we find, the glacialists have fallen back upon an
extraordinary hypothesis--to wit, that the whole north and south
regions of the globe, extending from the poles to 35° or 40° of north
and south latitude, were, in the Drift age, covered with enormous,
continuous sheets of ice, from one mile thick at its southern margin,
to three or five miles thick at the poles. As they find
drift-scratches upon the tops of mountains in Europe three to four
thousand feet high, and in New England upon elevations six thousand
feet high, it follows, according to this hypothesis, that the
ice-sheet must have been considerably higher than these mountains,
for the ice must have been thick enough to cover their tops, and high
enough and heavy enough above their tops to press down upon and
groove and scratch the rocks. And as the _striæ_ in Northern Europe
were found to disregard the conformation of the continent and the
islands of the sea, it became necessary to suppose that this polar
ice-sheet filled up the bays and seas, so that one could have passed
dry-shod, in that period, from France to the north pole, over a
steadily ascending plane of ice.

No attempt has been made to explain where all this

{p. 24}

ice came from; or what force lifted the moisture into the air which,
afterward descending, constituted these world-cloaks of frozen water.