less; but, that angular stones of the hardest
substance are thus made into that round gravel, which we find so
abundantly in many places forming the soil or loose materials of the
surface, is a conclusion which does not necessarily follow from
the premises, so far as there is another way of explaining those
appearances, and that by a cause much more proportioned to the effect.

The view which I take of the subject is this; first, that those
water-worn materials had their great roundness from the attrition
occasioned by the waves of the sea upon some former coast. Secondly,
that, after having been thus formed by agitation on the shores, and
transported into the deep, this gravel had contributed to the formation
of secondary strata, such as the puddingstone which has been described
in Part I. Chap 5, and 6; and, lastly that it has been from the decay
and resolution of those secondary strata, in the wafting operations of
the surface, that have come those rounded siliceous bodies, which could
not be thus worn by travelling in the longest river.]

I do not know in what manner M. Gensanne made his calculation; I would
suspect it was from partial, and not from general observations. We have
mountains in this country, and those not made of more durable materials
than what are common to the earth, which are not sensibly diminished
in their height with a thousand years. The proof of this are the Roman
roads made over some of those hills. I have seen those roads as distinct
as if only made a few years, with superficial pits beside them, from
whence had been dug the gravel or materials of which they had been
formed.

The natural operation of time upon the surface of this earth is to
dissolve certain substances, to disunite the solid bodies which are not
soluble, but which, in having been consolidated by fusion, are naturally
separated by veins and cutters, and to carry those detached bodies, by
the mechanic force of moving water, successively from stage to stage,
from places of a higher situation to those below.

Thus the beds of rivers are to be considered as the passages through
which both the lighter and heavier bodies of the land are gradually
travelling; and it is through them that those moveable bodies are from
time to time protruded towards the sea shore. But, in the course of
rivers, it often happens that there intervenes a lake; and this must be
considered as a repository for heavy bodies which had been transported
by