ly by the extinction of the species.

But the strongest argument against double creations may be drawn from
considering the case of mammifers{379} in which, from their nature and
from the size of their offspring, the means of distribution are more in
view. There are no cases where the same species is found in _very
remote_ localities, except where there is a continuous belt of land:
the Arctic region perhaps offers the strongest exception, and here we
know that animals are transported on icebergs{380}. The cases of lesser
difficulty may all receive a more or less simple explanation; I will
give only one instance; the nutria{381}, I believe, on the eastern coast
of S. America live exclusively in fresh-water rivers, and I was much
surprised how they could have got into rivulets, widely apart, on the
coast of Patagonia; but on the opposite coast I found these quadrupeds
living exclusively in the sea, and hence their migration along the
Patagonian coast is not surprising. There is no case of the same
mammifer being found on an island far from the coast, and on the
mainland, as happens with plants{382}. On the idea of double creations
it would be strange if the same species of several plants should have
been created in Australia and Europe; and no one instance of the same
species of mammifer having been created, or aboriginally existing, in
two as nearly remote and equally isolated points. It is more
philosophical, in such cases, as that of some plants being found in
Australia and Europe, to admit that we are ignorant of the means of
transport. I will allude only to one other case, namely, that of the
Mydas{383}, an Alpine animal, found only on the distant peaks of the
mountains of Java: who will pretend to deny that during the ice period
of the northern and southern hemispheres, and when India is believed to
have been colder, the climate might not have permitted this animal to
haunt a lower country, and thus to have passed along the ridges from
summit to summit? Mr Lyell has further observed that, _as in space, so
in time_, there is no reason to believe that after the extinction of a
species, the self-same form has ever reappeared{384}. I think, then, we
may, notwithstanding the many cases of difficulty, conclude with some
confidence that every species has been created or produced on a single
point or area.

{379} "We find no inexplicable cases of the same mammal inhabiting
distant points of the world." _Origin_,