Evidently There Are Now
Great Facilities For The Natural Productions Of Java To Spread Over
And Occupy The Whole Of These Islands, While Those Of Australia Would
Find Very Great Difficulty In Getting Across.
To account for the
present state of things, we should naturally suppose that Australia
was once much more closely
Connected with Timor than it is at present;
and that this was the case is rendered highly probable by the fact of
a submarine bank extending along all the north and west coast of
Australia, and at one place approaching within twenty miles of the
coast of Timor. This indicates a recent subsidence of North Australia,
which probably once extended as far as the edge of this bank, between
which and Timor there is an unfathomed depth of ocean.
I do not think that Timor was ever actually connected with Australia,
because such a large number of very abundant and characteristic groups
of Australian birds are quite absent, and not a single Australian
mammal has entered Timor - which would certainly not have been the case
had the lands been actually united. Such groups as the bower birds
(Ptilonorhynchus), the black and red cockatoos (Calyptorhynchus), the
blue wrens (Malurus), the crowshrikes (Cracticus), the Australian
shrikes (Falcunculus and Colluricincla), and many others, which abound
all over Australia, would certainly have spread into Timor if it had
been united to that country, or even if for any long time it had
approached nearer to it than twenty miles. Neither do any of the most
characteristic groups of Australian insects occur in Timor; so that
everything combines to indicate that a strait of the sea has always
separated it from Australia, but that at one period this strait was
reduced to a width of about twenty miles.
But at the time when this narrowing of the sea took place in one
direction, there must have been a greater separation at the other end
of the chain, or we should find more equality in the numbers of
identical and representative species derived from each extremity. It
is true that the widening of the strait at the Australian end by
subsidence, would, by putting a stop to immigration and intercrossing
of individuals from the mother country, have allowed full scope to the
causes which have led to the modification of the species; while the
continued stream of immigrants from Java, would, by continual
intercrossing, check such modification. This view will not, however,
explain all the facts; for the character of the fauna of the Timorese
group is indicated as well by the forms which are absent from it as by
those which it contains, and is by this kind of evidence shown to be
much more Australian than Indian. No less than twenty-nine genera, all
more or less abundant in Java, and most of which range over a wide
area, are altogether absent; while of the equally diffused Australian
genera only about fourteen are wanting. This would clearly indicate
that there has been, until recently, a wide separation from Java; and
the fact that the islands of Bali and Lombock are small, and are
almost wholly volcanic, and contain a smaller number of modified forms
than the other islands, would point them out as of comparatively
recent origin. A wide arm of the sea probably occupied their place at
the time when Timor was in the closest proximity to Australia; and as
the subterranean fires were slowly piling up the now fertile islands
of Bali and Lombock, the northern shores of Australia would be sinking
beneath the ocean. Some such changes as have been here indicated,
enable us to understand how it happens, that though the birds of this
group are on the whole almost as much Indian as Australian, yet the
species which are peculiar to the group are mostly Australian in
character; and also why such a large number of common Indian forms
which extend through Java to Bali, should not have transmitted a
single representative to the island further east.
The Mammalia of Timor as well as those of the other islands of the
group are exceedingly scanty, with the exception of bats. These last
are tolerably abundant, and no doubt many more remain to be discovered.
Out of fifteen species known from Timor, nine are found also in Java,
or the islands west of it; three are Moluccan species, most of which
are also found in Australia, and the rest are peculiar to Timor.
The land mammals are only seven in number, as follows: 1. The common
monkey, Macacus cynomolgus, which is found in all the Indo-Malayan
islands, and has spread from Java through Bali and Lombock to Timor.
This species is very frequent on the banks of rivers, and may have
been conveyed from island to island on trees carried down by hoods. 2.
Paradoxurus fasciatus; a civet cat, very common over a large part of
the Archipelago. 3. Felis megalotis; a tiger cat, said to be peculiar
to Timor, where it exists only in the interior, and is very rare. Its
nearest allies are in Java. 4. Cervus timoriensis; a deer, closely
allied to the Javan and Moluccan species, if distinct. 5. A wild pig,
Sus timoriensis; perhaps the same as some of the Moluccan species. 6.
A shrew mouse, Sorex tenuis; supposed to be peculiar to Timor. 7. An
Eastern opossum, Cuscus orientalis; found also in the Moluccas, if not
a distinct species.
The fact that not one of these species is Australia or nearly allied
to any Australian form, is strongly corroborative of the opinion that
Timor has never formed a part of that country; as in that case some
kangaroo or other marsupial animal would almost certainly be found
there. It is no doubt very difficult to account for the presence of
some of the few mammals that do exist in Timor, especially the tiger
cat and the deer. We must consider, however, that during thousands,
and perhaps hundreds of thousands of years, these islands and the seas
between them have been subjected to volcanic action.
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