Ragnarok : the age of fire and gravel

4

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WAS IT CAUSED BY ICEBERGS? 15

Again: if we suppose the supply to have existed on the Arctic coasts, the question comes,

Would the icebergs have carried it over the face of the continents? :

Mr. Croll has shown very clearly * that the icebergs nowadays usually sail down into the oceans without a

“scrap of débris of any kind upon them.

Again: how could the icebergs haye made the continuous scratchings or strie, found under the Drift nearly all over the continents of Europe and America ? Why, say the advocates of this theory, the icebergs press upon the bottom of the sea, and with the stones adhering to their base they make those striz.

But two things are necessary to this : First, that there should be a force great enough to drive the berg over the bottom of the sea when it has once grounded. We know of no such force. On the contrary, we do know that wherever a berg grounds it stays until it rocks itself to pieces or melts away. But, suppose there was such a propelling force, then it is evident that whenever the iceberg floated clear of the bottom it would cease to make the striz, and would resume them only when it nearly stranded again. That is to say, when the water was deep enough for the berg to float clear of the bottom of the sea, there could be no striw; when the water was too shallow, the berg would not float at all, and there would be no strix. The berg would mark the rocks only where it neither floated clear nor stranded. Hence we would find strie only at a certain elevation, while the rocks below or above that level would be free from them. But this is not the case with the drift-markings. They pass over mountains and down into the deepest valleys; they are

* “Climate and Time,” p. 282.