movement, we are to find the source of the clays which cover a large
part of our globe to a depth of hundreds of feet. Where are those
exposures of granite on the face of the earth from which ice or water
could have ground them? Granite, I repeat, comes to the surface only
in limited areas. And it must be remembered that clay is the product
exclusively of granite ground to powder. The clays are composed
exclusively of the products of disintegrated granite. They contain
but a trace of lime or magnesia or organic matters, and these can be
supposed to have been infiltrated into them after their arrival on
the face of the earth.[1] Other kinds of rock, ground up, form sand.
Moreover, we have seen that neither glaciers nor ice-sheets now
produce such clays.

We shall see, as we proceed, that the legends of mankind, in
describing the comet that struck the earth, represent it as
party-colored; it is "speckled" in one legend; spotted like a tiger
in another; sometimes it is a _white_ boar in the heavens; sometimes
a _blue_ snake; sometimes it is _red_ with the blood of the millions
that are to perish. Doubtless these separate formations, ground out
of the granite, from the mica, hornblende, or feldspar, respectively,
may, as I have said, under great laws, acted upon by magnetism or
electricity, have arranged themselves in separate lines or sheets, in
the tail of the comet, and hence we find that the clays of one region
are of one color, while those of another are of a different hue.
Again, we shall see that the legends represent the monster as
"winding," undulating, writhing, twisting, fold over fold, precisely
as the telescopes show us the comets do to-day.

[1. "American Cyclopædia," vol. iv, p. 650.]