but which do not occur in Borneo or Sumatra. Anion»b
Mammals the Rhinoceros javanicus is the most striking
example, for a distinct species is found in Borneo and
Sumatra, while the Javanese species occurs in Birmah and
even in Bengal. Among birds, the small ground dove,
Geopelia striata, and the curious bronze-coloured magpie,
Orypsirhina varians, are common to Java and Siam; while
there are in Java species of Pteruthius, Arrenga. Myio-
phonus, Zoothera, Sturnopastor, and Estrelda, the nearest
allies of which are found in various parts of India, while
nothing like them is known to inhabit Borneo or Sumatra.
Such a curious phenomenon as this can only be understood,
by supposing that, subsequent to the separation
of Java, Borneo became almost entirely submerged, and
on its re-elevation was for a time connected with the
Malay peninsula and Sumatra, but not with Java or
Siam. Any geologist who knows how strata have been
contorted and tilted up, and how elevations and depressions
must often have occurred alternately, not once or
twice only, but scores and even hundreds of times, will
have no difficulty in admitting that such changes as have
been here indicated are not in themselves improbable. The
existence of extensive coal-beds in Borneo and Sumatra, of
such recent origin that the leaves which abound in their
shales are scarcely distinguishable from those of the forests
which now cover the country, proves that such changes of
level actually did take place ; and it is a matter of much
interest, both to the geologist and to the philosophic
naturalist, to be able to form some conception of the order
of those changes, and to understand how they may have
resulted in the actual distribution of animal life in these
countries;—a distribution which often presents phenomena
so strange and contradictory, that without taking such
changes into consideration we are unable even to imagine
how they could have been brought about.