n thickness of solid rock
once extended over many square miles where the open sea now rolls;
without fully believing that the same sea which he sees beating the rock
at his feet has been the sole removing power.

{514} This question forms the subject of what is practically a
section of the final chapter of the _Origin_ (Ed. i. p. 480, vi. p.
657).

{515} _Origin_, Ed. i. p. 481, vi. p. 659.

Shall we then allow that the three distinct species of rhinoceros{516}
which separately inhabit Java and Sumatra and the neighbouring mainland
of Malacca were created, male and female, out of the inorganic materials
of these countries? Without any adequate cause, as far as our reason
serves, shall we say that they were merely, from living near each other,
created very like each other, so as to form a section of the genus
dissimilar from the African section, some of the species of which
section inhabit very similar and some very dissimilar stations? Shall we
say that without any apparent cause they were created on the same
generic type with the ancient woolly rhinoceros of Siberia and of the
other species which formerly inhabited the same main division of the
world: that they were created, less and less closely related, but still
with interbranching affinities, with all the other living and extinct
mammalia? That without any apparent adequate cause their short necks
should contain the same number of vertebrae with the giraffe; that their
thick legs should be built on the same plan with those of the antelope,
of the mouse, of the hand of the monkey, of the wing of the bat, and of
the fin of the porpoise. That in each of these species the second bone
of their leg should show clear traces of two bones having been soldered
and united into one; that the complicated bones of their head should
become intelligible on the supposition of their having been formed of
three expanded vertebrae; that in the jaws of each when dissected young
there should exist small teeth which never come to the surface. That in
possessing these useless abortive teeth, and in other characters, these
three rhinoceroses in their embryonic state should much more closely
resemble other mammalia than they do when mature. And lastly, that in a
still earlier period of life, their arteries should run and branch as in
a fish, to carry the blood to gills which do not exist. Now these three
species of rhinoceros closely resemble each other; more closely t