ons.

But there is another set of facts, which help us on another step towards
the case of the Javanese mountain flora. On the higher slopes of
the Himalayas, on the tops of the mountains of Central India and of
Abyssinia, a number of plants occur which, though not identical with
those of European mountains, belong to the same genera, and are said by
botanists to represent them; and most of these could not exist in the
warm intervening plains. Mr. Darwin believes that this class of facts
can be explained in the same way; for, during the greatest severity of
the glacial epoch, temperate forms of plants will have extended to the
confines of the tropics, and on its departure, will have retreated up
these southern mountains, as well as northward to the plains and hills
of Europe. But in this case, the time elapsed, and the great change of
conditions, have allowed many of these plants to become so modified that
we now consider them to be distinct species. A variety of other facts
of a similar nature have led him to believe that the depression of
temperature was at one time sufficient to allow a few north-temperate
plants to cross the Equator (by the most elevated routes) and to reach
the Antarctic regions, where they are now found. The evidence on which
this belief rests will be found in the latter part of CHAPTER II. of the
"Origin of Species"; and, accepting it for the present as an hypothesis,
it enables us to account for the presence of a flora of European type on
the volcanoes of Java.

It will, however, naturally be objected that there is a wide expanse
of sea between Java and the continent, which would have effectually
prevented the immigration of temperate fortes of plants during the
glacial epoch. This would undoubtedly be a fatal objection, were there
not abundant evidence to show that Java has been formerly connected with
Asia, and that the union must have occurred at about the epoch required.
The most striking proof of such a junction is, that the great Mammalia
of Java, the rhinoceros, the tiger, and the Banteng or wild ox, occur
also in Siam and Burmah, and these would certainly not have been
introduced by man. The Javanese peacock and several other birds are
also common to these two countries; but, in the majority of cases,
the species are distinct, though closely allied, indicating that a
considerable time (required for such modification) has elapsed since the
separation, while it has not been so long as to