It is thus that, in finding the relics of sea-animals of every kind
in the solid body of our earth, a natural history of those animals
is formed, which includes a certain portion of time; and, for the
ascertaining this portion of time, we must again have recourse to the
regular operations of this world. We shall thus arrive at facts which
indicate a period to which no other species of chronology is able to
remount.

In what follows, therefore, we are to examine the construction of the
present earth, in order to understand the natural operations of time
past; to acquire principles, by which we may conclude with regard to the
future course of things, or judge of those operations, by which a world,
so wisely ordered, goes into decay; and to learn, by what means such a
decayed world may be renovated, or the waste of habitable land upon the
globe repaired.

This, therefore, is the object which we are to have in view during this
physical investigation; this is the end to which are to be directed all
the steps in our cosmological pursuit.

The solid parts of the globe are, in general, composed of sand, of
gravel, of argillaceous and calcareous strata, or of the various
compositions of these with some other substances, which it is not
necessary now to mention. Sand is separated and sized by streams and
currents; gravel is formed by the mutual attrition of stones agitated
in water; and marly, or argillaceous strata, have been collected, by
subsiding in water with which those earthy substances had been floated.
Thus, so far as the earth is formed of these materials, that solid body
would appear to have been the production of water, winds, and tides.