t place,
he says, shells and other marine productions are found all over the
surface and in the interior of the dry land; and all calcareous rocks
are made up of their remains. Secondly, a great many of these shells
which are found in Europe are not now to be met with in the adjacent
seas; and, in the slates and other deep-seated deposits, there are
remains of fishes and of plants of which no species now exist in our
latitudes, and which are either extinct, or exist only in more northern
climates. Thirdly, in Siberia and in other northern regions of
Europe and of Asia, bones and teeth of elephants, rhinoceroses, and
hippopotamuses occur in such numbers that these animals must once have
lived and multiplied in those regions, although at the present day they
are confined to southern climates. The deposits in which these remains
are found are superficial, while those which contain shells and other
marine remains lie much deeper. Fourthly, tusks and bones of elephants
and hippopotamuses are found not only in the northern regions of the old
world, but also in those of the new world, although, at present, neither
elephants nor hippopotamuses occur in America. Fifthly, in the middle of
the continents, in regions most remote from the sea, we find an infinite
number of shells, of which the most part belong to animals of those
kinds which still exist in southern seas, but of which many others have
no living analogues; so that these species appear to be lost, destroyed
by some unknown cause. It is needless to inquire how far these
statements are strictly accurate; they are sufficiently so to justify
Buffon's conclusions that the dry land was once beneath the sea; that
the formation of the fossiliferous rocks must have occupied a vastly
greater lapse of time than that traditionally ascribed to the age of
the earth; that fossil remains indicate different climatal conditions
to have obtained in former times, and especially that the polar regions
were once warmer; that many species of animals and plants have become
extinct; and that geological change has had something to do with
geographical distribution.

But these propositions almost constitute the frame-work of
palaeontology. In order to complete it but one addition was needed, and
that was made, in the last years of the eighteenth century, by William
Smith, whose work comes so near our own times that many living men may
have been personally acquainted with him. This modest land-su