Ragnarok : the age of fire and gravel

80 THE COMET.

But it would be absurd to suppose that the beds of rivers could haye furnished the immeasurable volumes of gravel found over a great part of the world in the driftdeposits. :

And the drift-gravel is different from the gravel of the sea or rivers.

Geikie says, speaking of the “till”:

“There is something yery peculiar about the shape of the stones. They are neither round and oval, like the pebbles in river-gravel, or the shingle of the sea-shore, nor are they sharply angular like newly-fallen débris at the base of a cliff, although they more closely resemble the latter than the former. They are, indeed, angular in shape, but the sharp corners and edges have invariably been smoothed away. . . . Their shape, as will be seen, is by no means their most striking peculiarity. Each is smoothed, polished, and covered with striz or scratches, some of which are delicate as the lines traced by an etching-needle, others deep and harsh as the scores made by the plow upon arock. And, what is worthy of note, most of the scratches, coarse and fine together, seem to run parallel to the longer diameter of the stones, which, however, are scratched in many other directions as well.” *

Let me again summarize :

I. Comets consist of a blazing nucleus and a mass of ponderable, separated matter, such as stones, gravel, claydust, and gas. °

II. The nucleus gives out great heat and masses of burning gas.

II. Luminous gases surround the nucleus.

IV. The drift-clays are the result of the grinding up of granitic rocks.

VY. No such deposits, of anything like equal magnitude, could have been formed on the earth.

* “The Great Ice Age,” p. 13.