s also been a
great lapse of time or a great change of conditions. The animals, for
instance, of the newest tertiary rocks, in any part of the world, are
always, and without exception, found to be closely allied with those
which now live in that part of the world. For example, in Europe,
Asia, and Africa, the large mammals are at present rhinoceroses,
hippopotamuses, elephants, lions, tigers, oxen, horses, etc.; and if
you examine the newest tertiary deposits, which contain the animals
and plants which immediately preceded those which now exist in the same
country, you do not find gigantic specimens of ant-eaters and kangaroos,
but you find rhinoceroses, elephants, lions, tigers, etc.,--of different
species to those now living,--but still their close allies. If you turn
to South America, where, at the present day, we have great sloths and
armadilloes and creatures of that kind, what do you find in the newest
tertiaries? You find the great sloth-like creature, the 'Megatherium',
and the great armadillo, the 'Glyptodon', and so on. And if you go to
Australia you find the same law holds good, namely, that that condition
of organic nature which has preceded the one which now exists, presents
differences perhaps of species, and of genera, but that the great types
of organic structure are the same as those which now flourish.

What meaning has this fact upon any other hypothesis or supposition than
one of successive modification? But if the population of the world, in
any age, is the result of the gradual modification of the forms which
peopled it in the preceding age,--if that has been the case, it is
intelligible enough; because we may expect that the creature that
results from the modification of an elephantine mammal shall be
something like an elephant, and the creature which is produced by the
modification of an armadillo-like mammal shall be like an armadillo.
Upon that supposition, I say, the facts are intelligible; upon any
other, that I am aware of, they are not.

So far, the facts of palaeontology are consistent with almost any
form of the doctrine of progressive modification; they would not be
absolutely inconsistent with the wild speculations of De Maillet, or
with the less objectionable hypothesis of Lamarck. But Mr. Darwin's
views have one peculiar merit; and that is, that they are perfectly
consistent with an array of facts which are utterly inconsistent with
and fatal to, any other hypothesis of progressive m