III. The action of glaciers.

IV. The action of a continental ice-sheet.

We will consider these several theories in their order.

[1. "Popular Science Monthly," July, 1876, p. 290.]

{p. 10}

CHAPTER III.

THE ACTION OF WAVES.

WHEN men began, for the first time, to study the drift deposits, they
believed that they found in them the results of the Noachic Deluge;
and hence the Drift was called the Diluvium, and the period of time
in which it was laid down was entitled the Diluvial age.

It was supposed that--

"Somehow and somewhere in the far north a series of gigantic waves
was mysteriously propagated. These waves were supposed to have
precipitated themselves upon the land, and then swept madly over
mountain and valley alike, carrying along with them a mighty burden
of rocks and stones and rubbish. Such deluges were called 'waves of
translation.'"[1]

There were many difficulties about this theory: