for explaining the general appearance of that
which was once the bottom of the sea being now found forming the summits
of our mountains; but surely this philosopher will acknowledge, that
those natural appearances, in any particular place, will be the same,
whether we suppose the bottom of the sea to have been raised, as in the
present theory, or the surface of the sea to have sunk according to his
hypothesis. For, it is equally easy to suppose a portion of the earth
to have been raised all this height, as to suppose all the rest of the
surface of the globe to have sunk an equal space, while a small portion
of the bottom of the sea, remaining here and there fixed in its place,
became the highest portion of the globe. Consequently, whatever evidence
this philosopher shall find in support of his theory of the present
earth, (a subject which it is not our purpose to examine) it cannot be
allowed that he has here brought any argument capable of disproving the
elevation of the bottom of the sea; a supposition which other theories
may require.

I would now observe, in relation to the present theory, that so far
as this author has reasoned justly from natural appearances, his
conclusions will be found to confirm the present supposition, that there
is to be perceived the distinction of primordial, and that of secondary,
in the masses of this earth, without altering the general theory either
with respect to the original formation of those masses, or to their
posterior production.

Here one of two things must be allowed; either that those strata
of schistus had been broken and distorted under a mass of other
superincumbent strata; or that those superincumbent strata had been
deposited upon the broken and distorted strata at the bottom of the sea.
Our author, who has examined the subject, inclines to think, that this
last has been the case. If, therefore, strata had been deposited upon
broken and bare rocks of schistus, it is probable that these had been
sunk in the sea after having been exposed to the atmosphere, and served
the purpose of land upon the globe.[31]

[Note 31: This is also supported by another very interesting observation
contained in this letter. M. de Luc observes, that in this country the
schistus is generally covered by strata of lime-stone, and that these
lime-stone strata are again covered with those of sand-stone, in which
are found a great many fragments of schistus lying flat. Therefore,
while those sand