of its being complete, it threw light upon the most minute processes of
the arts. In our time the numerous points of affinity existing between
it and the curious discoveries of the geologists, have made it, if I may
use the expression, a work for the occasion. To point out the ultimate
relation which exists between these two kinds of researches would be to
present the most important part of the discoveries of Fourier, and to
show how happily our colleague, by one of those inspirations reserved
for genius, had chosen the subject of his researches.

The parts of the earth's crust, which the geologists call the
sedimentary formations, were not formed all at once. The waters of the
ocean, on several former occasions, covered regions which are situated
in the present day in the centre of the continent. There they deposited,
in thin horizontal strata, a series of rocks of different kinds. These
rocks, although superposed like the layers of stones of a wall, must not
be confounded together; their dissimilarities are palpable to the least
practised eye. It is necessary also to note this capital fact, that
each stratum has a well-defined limit; that no process of transition
connects it with the stratum which it supports. The ocean, the original
source of all these deposits, underwent then formerly enormous changes
in its chemical composition to which it is no longer subject.

With some rare exceptions, resulting from local convulsions the effects
of which are otherwise manifest, the order of antiquity of the
successive strata of rocks which form the exterior crust of the globe
ought to be that of their superposition. The deepest have been formed at
the most remote epochs. The attentive study of these different envelops
may aid us in ascending the stream of time, even beyond the most remote
epochs, and enlightening us with respect to those stupendous revolutions
which periodically overwhelmed continents beneath the waters of the
ocean, or again restored them to their former condition. Crystalline
rocks of granite upon which the sea has effected its original deposits
have never exhibited any remains of life. Traces of such are to be found
only in the sedimentary strata.

Life appears to have first exhibited itself on the earth in the form of
vegetables. The remains of vegetables are all that we meet with in the
most ancient strata deposited by the waters; still, they belong to
plants of the simplest structure,--to ferns, to spec