There is nothing of which we have more distinct experience than this,
That, universally upon the surface of the earth, the solid parts are
dissolving and always going into decay; whereas, at a sufficient
depth below, they are found in their natural consolidated state. The
operations of man in digging into the ground, as well as the sections
of the earth so often formed by brooks and rivers, affords such ample
testimony of this truth that nothing farther need be observed upon this
head only that this is a most important operation in the natural economy
of the globe, and forms a subject of the greatest consequence in the
present Theory of the Earth, which holds for principle, that the strata
are consolidated in the mineral regions far beyond reach of human
observation.

Consistently with this view of things, the strata or regular solid
parts, under the soil or travelled earth, should be found in some shape
corresponding to the represented state of those things, when affected
by the powers which have acted upon the surface of the earth. Here,
accordingly, the strata are always to be observed with those marks of
resolution, of fracture, and of separation, which have most evidently
arisen from the joint operation of those several causes that have been
now explained. But though every operation of the globe be necessarily
required for the explanation of those appearances which we now examine,
it is principally the action of the sun and atmosphere, and the
operations of the waters flooding the surface of the earth, that form
the proper subject of the present investigation.

It must not be imagined that, from the present state of things, we may
be always able to explain every particular appearance of this kind which
occurs; for example, why upon an eminence, or the summit of a ridge of