DISTRIBUTION OV MAN. 



59 



elevation of only 300 feet would nearly double the extent of tropical Asia. Over the whole of the 

 Java Sea, the Straits of Malacca, the Gulf of Siam, and the southern part of the China sea, ships 

 can anchor in less than fifty fathoms. A vast submarine plain unites together the ajjparently 

 disjointed parts of the Indian zoological region, and abruptly tenninates exactly at its limits in 

 an unfathomable ocean. The deep sea of the Moluccas comos up to the very Coasts of Northern 

 IJorneo, to the Strait of Lombock in the south, and to near the middle of the Strait of Macassar.* 

 May we not, therefore, from these facts very fairly conclude that, according to the system of 

 alternate bands of elevation and depression, which seems very generally to prevail, the last great 

 rising movement of the volcanic range of Java and Sumatra was accompanied by the depression that 

 now scj)arates them from Borneo, and from the Continent ?"t 



The fauna and flora of the Malayan islands, too, is closely allied to the fauna of the neigh- 

 bouring continent. The elephant, rhinoceros, and tapir, found in Sumatra, are also found in 

 Southern Asia. Every family, most of the genera and many of the species of birds and insects, 

 which are found on these islands, are also to be met with on the continent. On the other 

 hand, the species found in New Guinea, Celebes, and the islands to the east and south, are of a 

 totally different t}'pe, in many respects distinct and peculiar to themselves, but in others showing 

 Australian affinities. 



Reasoning from these facts, geologists have conceived that while Sumatra, Java, Borneo, and 

 the Philippine Islands, are parts of Asia separated from it at no distant period, Celebes, Timor, 

 the Moluccas, New Guinea, and Australia, are remnants of a vast submerged continent, traces 

 of the existence of which appear in the coral islands of the Pacific Ocean, and in the affinities 



* It is perhaps right to say that it ia not to be 

 considered as absolutely settled, that the Straits of Mac- 

 ussar iire of great depth all through. The western or 

 Malayan side is shallow all along the coast of Borneo. 

 The soundings which have been taken show great depth 

 on the east, both to the north and south, but in the centre 

 an equal depth is not so well ascertained. In the largest 

 and most detailed map of soundings which has been 

 published, viz. that by Jacob Swartz, the soundings taken 

 at the middle of the straits gradually increase on the 

 western side from fourteen to thirty-five fathoms, and a 

 few scattered soundings in mid-channel are noted where 

 the depth varies from twenty to forty fathoms : these 

 are continued until within about ten miles of the coast 

 of Celebes, when no more are recorded. 



One is apt to suppose on seeing this, that a bank 

 of from twenty to forty fathoms in depth extends across 

 the middle part of the straits ;_ but in the first place 

 the want of soundings for ten miles across on the side 

 where we know the water to be deepest, and where a 

 little to the north and south no soundings are to be had 

 with a hundred-fathom line, prevent us assuming this ; 

 and in the next place, on personal inquiry at Mr. Wal- 

 lace, he assures me of his firm conviction that there is 

 deep water there as well as on each side of it, and informs 

 rae that the scattered sounding.? to which I have referred 

 are not to be taken as indicating the general depth around 

 the spot marked, but merely the depth at the particu- 



lar spot, usually a reef or a sand-bank, where they occur 

 He had met with residents who remembered the taking 

 of these soundings, and they informed him that the way 

 in which the ofl^cer who was charged with the duty pro- 

 ceeded was this : he allowed his vessel to drift about 

 during the night with a light anchor attached to a forty- 

 fathom cable hanging overboard, and when this caught 

 upon a bank or reef, then soundings were taken and 

 registered, but his forty-fathom anchor might have been 

 swinging about all around, without touching the ground. 

 With this information to guide us in estimating the value 

 of the soundings in Jacob Swartz's map, it is clear that 

 they are worth nothing for our purpo.se, unless where 

 numerous and close together. I therefore have adopted 

 Mr. Wallace's view, and assumed that the water on the 

 eastern side of the Straits of Macassar is throughout of 

 very great depth. 



+ See paper by Mr. Wallace in Linn. Soc. Proc, Feb. 

 1860. See also a communication by Mr. Wallace in the 

 Ibis for October 1859. On this last point I am not pre- 

 pared at once to go unreservedly along with Mr. Wallace. 

 It may be that the surrounding depression was due to a 

 more extensive general previous sinking, and that the area 

 in question has been again raised by the volcanic action 

 referred to by Mr. Wallace, stretching through or run- 

 ning across the general depression. The theory of alter- 

 nate bands of elevation and depression may be ])ushed too 

 far. 



