anatomists (and those not of the first order) would have been induced by
mere love of detail, as such, to study the minutiae of osteology, were
it not that in such minutiae lie the only keys to the most interesting
riddles offered by the extinct animal world.

These assuredly are great and solid gains. Surely it is matter for no
small congratulation that in half a century (for paleontology, though
it dawned earlier, came into full day only with Cuvier) a subordinate
branch of biology should have doubled the value and the interest of the
whole group of sciences to which it belongs.

But this is not all. Allied with geology, paleontology has established
two laws of inestimable importance: the first, that one and the same
area of the earth's surface has been successively occupied by very
different kinds of living beings; the second, that the order of
succession established in one locality holds good, approximately, in
all.

The first of these laws is universal and irreversible; the second is an
induction from a vast number of observations, though it may possibly,
and even probably, have to admit of exceptions. As a consequence of
the second law, it follows that a peculiar relation frequently subsists
between series of strata, containing organic remains, in different
localities. The series resemble one another, not only in virtue of a
general resemblance of the organic remains in the two, but also in
virtue of a resemblance in the order and character of the serial
succession in each. There is a resemblance of arrangement; so that the
separate terms of each series, as well as the whole series, exhibit a
correspondence.