| Contrasts of Vegetation. --
Placed immediately upon the Equator and surrounded by extensive
oceans, it is not surprising that the various islands of the
Archipelago should be almost always clothed with a forest vegetation
from the level of the sea to the summits of the loftiest mountains.
This is the general rule. Sumatra, New Guinea, Borneo, the
Philippines and the Moluccas, and the uncultivated parts of Java and
Celebes, are all forest countries, except a few small and
unimportant tracts, due perhaps, in some cases, to ancient
cultivation or accidental fires. To this, however, there is one
important exception in the island of Timor and all the smaller
islands around it, in which there is absolutely no forest such as
exists in the other islands, and this character extends in a lesser
degree to Flores, Sumbawa, Lombock, and Bali.
In Timor the most common trees are
Eucalypti of several species, also characteristic of Australia, with
sandalwood, acacia, and other sorts in less abundance. These are
scattered over the country more or less thickly, but, never so as to
deserve the name of a forest. Coarse and scanty grasses grow beneath
them on the more barren hills, and a luxuriant herbage in the
moister localities. In the islands between Timor and Java there is
often a more thickly wooded country abounding in thorny and prickly
trees. These seldom reach any great height, and during the force of
the dry season they almost completely lose their leaves, allowing
the ground beneath them to be parched up, and contrasting strongly
with the damp, gloomy, ever-verdant forests of the other islands.
This peculiar character, which extends in a less degree to the
southern peninsula of Celebes and the east end of Java, is most
probably owing to the proximity of Australia. The south-east
monsoon, which lasts for about two-thirds of the year (from March to
November), blowing over the northern parts of that country, produces
a degree of heat and dryness which assimilates the vegetation and
physical aspect of the adjacent islands to its own. A little further
eastward in Timor and the Ke Islands, a moister climate prevails;
the southeast winds blowing from the Pacific through Torres Straits
and over the damp forests of New Guinea, and as a consequence, every
rocky islet is clothed with verdure to its very summit. Further west
again, as the same dry winds blow over a wider and wider extent of
ocean, they have time to absorb fresh moisture, and we accordingly
find the island of Java possessing a less and less arid climate,
until in the extreme west near Batavia, rain occurs more or less all
the year round, and the mountains are everywhere clothed with
forests of unexampled luxuriance.
Contrasts in Depth of Sea. -- It was
first pointed out by Mr. George Windsor Earl, in a paper read before
the Royal Geographical Society in 1845, and subsequently in a
pamphlet "On the Physical Geography of South-Eastern Asia and
Australia", dated 1855, that a shallow sea connected the great
islands of Sumatra, Java, and Borneo with the Asiatic continent,
with which their natural productions generally agreed; while a
similar shallow sea connected New Guinea and some of the adjacent
islands to Australia, all being characterised by the presence of
marsupials.
We have here a clue to the most radical
contrast in the Archipelago, and by following it out in detail I
have arrived at the conclusion that we can draw a line among the
islands, which shall so divide them that one-half shall truly belong
to Asia, while the other shall no less certainly be allied to
Australia. I term these respectively the Indo-Malayan and the
Austro-Malayan divisions of the Archipelago.
On referring to pages 12, 13, and 36 of
Mr. Earl's pamphlet, it will be seen that he maintains the former
connection of Asia and Australia as an important part of his view;
whereas, I dwell mainly on their long continued separation.
Notwithstanding this and other important differences between us, to
him undoubtedly belongs the merit of first indicating the division
of the Archipelago into an Australian and an Asiatic region, which
it has been my good fortune to establish by more detailed
observations. |