terials of which the soil is formed; this soil then
partakes of the nature of those solid parts, whether more simple or
more compound. There is, however, another subject of variety, or still
greater composition in soils; this is the transportation of materials
from a distance; and this, in general, is performed by the ablution of
water, in following the declivity of the surface. But sand is sometimes
travelled by the wind, and proceeds along the surface of the earth,
without regard to the declivity, and changes the nature of soil in those
places which happen to be exposed to this accident.

There cannot be any extensive, great, or distant travelling of sand or
soil by means of the wind, except in those places which are sterile for
want of rain, and thus are destitute of rivers and of streams; for,
these running waters form every where a bar to this progressive movement
of the soil, even if the sterility or dryness should permit the blowing
of the sand. But the operation of streams and rivers, carrying soil and
stones along the surface of the earth, is constant, great, and general
over all the globe, so far as a superfluity of water, in the seasons of
rain, falls upon the earth.

From the amazing quantity of those far travelled materials, which in
many places are found upon the surface of the ground, we may with
certainty conclude, that there has been a great consumption of the
most hard and solid parts of the land; and therefore that there must
necessarily have been a still much greater destruction of the more soft
and tender substances, and the more light and subtile parts which,
during those operations of water, had been floated away into the sea.
This appears from the enormous quantities of stones and gravel which
have been transported at distances that seem incredible, and deposited
at heights above the present rivers, which renders the conveyance of
those bodies altogether inconceivable by any natural operation, or
impossible from the present shape of the surface. This therefore leads
us to conclude, that the surface of the earth must have been greatly
changed since the time of those deposits of certain foreign materials
of the soil. Examples of this kind have been already given. I shall now
give one from the Journal de Physique.

"Les bords du Rhone aux environs de Lyon, et sur la longueur de quarante
lieues, et de plus, des montagnes entieres, dans le meme pays, sont
formes de pierres dont on ne trouve les anal