immense deep lake, which, no doubt, is a thing that may have been,
like many others which actually exist. But then he likewise supposes
a particular revolution of things, in which one side of that stony
circuit, forming the bason of the lake, had been destroyed while the
water was discharged. It is this last hypothesis which appears to me to
be a thing altogether inadmissible, according to the natural order of
things.

In order to see this, it must be considered, that the side of the bason,
which has disappeared, must have been either of similar materials to
those which we see now remaining, or it must be supposed as composed of
loose materials, such as had been more soft, or of those that might be
easily dissolved and washed away by the water. If this last had been
the state of things, there would not have been occasion for any violent
catastrophe, as M. Reboul has supposed; the natural overflowing of the
lake had been sufficient to wear the mound by which the water had
been detained, and to carry away those materials so as one side might
disappear. If, again, this mound had been formed of rock, like what
remains of those mountains, in that case, the catastrophe, which this
author has suggested as the cause of that destruction, would have been
ineffectual to procure that end; for, though such a _debacle_ might have
carried away a great mass of loose materials, it could not have moved a
mound of solid rock.

That of which we have here undoubted information, and that which I am
labouring to generalise by comparing similar phenomena, such as are to
be found over all the earth, is this, That the natural operations of
the atmospheric elements decompose the solid rocks, break down the
consolidated strata, waste and wash away those loosened materials of the
mountains, and thus excavate the valleys, as the channels by which an
indefinite quantity of materials are to be transported to the sea for
the construction of future continents. It is this operation of nature
which we see performed, more or less, every day, which some natural
philosophers have such difficulty in admitting at all, and which others
overlook in seeking for some wonderful operation to produce the effect
in a shorter time. The prodigious waste that evidently appears, in
many places, to have been made of the solid land, and the almost
imperceptible effects of the present agents which appear, have given,
occasion to those different opinions concerning that whi