er of heat and operation
of fusion must have been employed in consolidating strata of loose
materials, which had been collected together and amassed at the bottom
of the ocean. It will, therefore, be proper to consider, what are the
appearances in consolidated strata that naturally should follow, on the
one hand, from fluidity having been, in this manner, introduced by means
of heat, and, on the other, from the interstices being filled by means
of solution; that so we may compare appearances with the one and other
of those two suppositions, in order to know that with which they may be
only found consistent.

The consolidation of strata with every different kind of substance was
found to be inconsistent with the supposition, that aqueous solution
had been the means employed for this purpose. This appearance, on the
contrary, is perfectly consistent with the idea, that the fluidity of
these bodies had been the effect of heat; for, whether we suppose the
introduction of foreign matter into the porous mass of a stratum for its
consolidation, or whether we shall suppose the materials of the mass
acquiring a degree of softness, by means of which, together with an
immense compression, the porous body might be rendered solid; the power
of heat, as the cause of fluidity and vapour, is equally proper and
perfectly competent. Here, therefore, appearances are as decidedly in
favour of the last supposition, as they had been inconsistent with the
first.

But if strata have been consolidated by means of aqueous solution, these
masses should be found precisely in the same state as when they were
originally deposited from the water. The perpendicular section of those
masses might show the compression of the bodies included in them, or of
which they are composed; but the horizontal section could not contain
any separation of the parts of the stratum from one another.

If, again, strata have been consolidated by means of heat, acting in
such a manner as to soften their substance, then, in cooling, they must
have formed rents or separations of their substance, by the unequal
degrees of contraction which the contiguous strata may have suffered.
Here is a most decisive mark by which the present question must be
determined.

There is not in nature any appearance more distinct than this of the
perpendicular fissures and separations in strata. These are generally
known to workmen by the terms of veins or backs and cutters; and there
is no