3462. GEOLOGY, Theories of.—
With respect
to the inclination of the strata of rocks,
I had observed them between the Blue Ridge
and North Mountains in Virginia, to be parallel
with the pole of the earth. I observed the
same thing in most instances in the Alps, between
Cette and Turin; but in returning along
the precipices of the Apennines, where they
hang over the Mediterranean, their direction
was totally different and various. You mention
that in our Western country they are horizontal.
This variety proves they have not been
formed by subsidence, as some writers of the
theories of the earth have pretended; for then
they should always have been in circular strata,
and concentric. It proves, too, that they have
not been formed by the rotation of the earth
on its axis, as it might have been suspected,
had all these strata been parallel with that axis.
They may, indeed, have been thrown up by
explosions, as Whitehurst supposes, or have
been the effect of convulsions. But there can
be no proof of the explosion, nor is it probable
that convulsions have deformed every spot of
the earth. It is now generally agreed that rock
grows, and it seems that it grows in layers in
every direction, as the branches of trees grow
in all directions. Why seek further the solution
of this phenomenon? Everything in nature
decays. If it were not reproduced then
by growth there should be a chasm.—
To Charles Thomson. Washington ed. ii, 276.
Ford ed., iv, 448.
(P.
1787)
