The Malay archipelago : the land of the orang-utan ... - Wallace Online

;112 THE MALAY ARCHIPELAGO. [chap.Although on the map Banca appears so close to Sumatra, thisdoes not arise from its having been recently separated from itfor the adjacent district of Palembang is new land, being a greatalluvial swamp formed by torrents from tlie mountains a hundredmiles distant. Banca, on the other hand, agrees with Malacca,Singapore, and the inter\'ening island of Lingen, in being formedof granite and laterite ; and these have all most likely onceformed an extension of the Malay peninsula. As the rivers ofBorneo and Sumatra have been for ages filling up the interveningsea, we may be sure that its depth has recently beengreater, and it is very probable that those large islands werenever directly connected with each other excej^t through theMalay peninsula. At that period the same species of squirreland Pitta may have inhabited all these countries ; but when thesubterranean disturbances occurred which led to the elevation ofthe volcanoes of Sumatra, the small island of Banca may liavebeen separated first, and its productions being thus isolatedmight be gradually modified before the separation of the largerislands liad been completed. As the southern part of Sumatraextended eastward and formed the narrow straits of Banca,many birds and insects and some ^Mammalia would cross fromone to the other, and thus produce a general similarity of i^roductions,while a few of the older inhabitants remained, toreveal by their distinct forms their different origin. Unlesswe supjDose some such changes in physical geography to haveoccurred, the presence of peculiar species of birds and mammalsin such an island as Banca is a hopeless puzzle ; and Ithink I have shown that the changes required are by no meansso imjirobable as a mere glance at the map would lead us tosuppose.For our next example let us take the great islands of Sumatraand Java. These approach so closely together, and the chain ofvolcanoes that runs through them gives such an air of unity tothe two, that the idea of tlieir having been recently disseveredis immediately suggested. The natives of Java, however, gofurther than this ; for they actually have a tradition of thecatastrophe which broke tliem asunder, and fix its date at notmuch more than a thousand years ago. It becomes interesting,therefore, to see what support is given to this view by thecomparison of their animal jjroductions.The Mammalia have not been collected with suificient completenessin both islands to make a general compai'ison of muchvalue, and so many species have been obtained only as livespecimens in captivity, that tlieir locality has often been erroneouslygiven—the island in whicli they were obtained beingsubstituted for that from which they originally came. Takinginto consideration only those whose distribution is more accuratelyknown, we learn that Sumatra is, in a zoological sense,more nearly related to Borneo than it is to Java. The greatman-like apes, the elephant, the tapir, and the Malay bear, are