Ragnarok : the age of fire and gravel

CAUSED BY CONTINENTAL ICE-SHEETS? 25

sea at a higher level than now, were the warm inter-glacial periods, when the country was free of snow and ice, and a mild and equable condition of climate prevailed. This is the conclusion toward which we are being led by the more recent revelations of surface-geology, and also by certain facts connected with the geographical distribution of plants and animals during the Glacial epoch.” *

H. B. Norton says:

“When we come to study the cause of these phenomena, we find many perplexing and contradictory theories in the field. A favorite one is that of vertical elevation. But it seems impossible to admit that the circle inclosed within the parallel of 40°—some seven thousand miles in diameter—could have been elevated to such a height as to produce this remarkable result. This would be a supposition hard to reconcile with the present proportion of land and water on the surface of the globe and with the phenomena of terrestrial contraction and gravitation.” +

We have seen that the surface-rocks underneath the Drift are scored and grooved by some external force. Now we find that these markings do not all run in the same direction ; on the contrary, they cross each other in an extraordinary manner. The cut on the following page illustrates this.

If the direction of the motion of the ice-sheets, which caused these markings, was,—as the glacialists allege,always from the elevated region in the north to the lower ground in the south, then the markings must always have been in the same direction ; given a fixed cause, we must have always a fixed result. We shall see, as we go on in this argument, that’the deposition of the “till” was instantaneous; and, as these markings were made before or at the same time the “till” was laid down, how could the land

* “Olimate and Time,” p. 391. + “ Popular Science Montlily,” October, 1879, p. 833.