CHAP. XVII BORNEO AND JAVA 375 



Peninsula is about 350 miles, and it is nearly as far from 

 Sumatra and Java, while it is more than 600 miles frona 

 the Siamese Peninsula, opposite to which its long northern 

 coast extends. There is, I believe, nowhere else upon 

 the globe, an island so far from a continent, yet separated 

 from it by so shallow a sea. Recent changes of sea and 

 land must have occurred here on a grand scale, and this 

 adds to the interest attaching to the study of this large 

 island. 



The internal geography of Borneo is somewhat peculiar. 

 A large portion of its surface is lowland, consisting of great 

 alluvial valleys which penetrate far into the interior ; while 

 the mountains except in the north, are of no great 

 elevation, and there are no extensive plateaux. A 

 subsidence of 500 feet would allow the sea to fill the great 

 valleys of the Pontianak, Baujarmassing, and Coti rivers, 

 almost to the centre of the island, greatly reducing its 

 extent, and causing it to resemble in form the island^ of 

 Celebes to the east of it. 



In geological structure Borneo is thoroughly continental, 

 possessing formations of all ages, with basalt and crystalline 

 rocks, but no recent volcanoes. It possesses vast beds of 

 coal of Tertiary age ; and these, no less than the great 

 extent of alluvial deposits in its valleys, indicate great 

 changes of level in recent geological times. 



Having thus briefly indicated those physical features of 

 Borneo which are necessary for our inquiry, let us turn to 

 the organic world. 



Neither as regards this great iskmd nor those which 

 surround it, have we the amount of detailed information in 

 a convenient form that is required for a full elucidation of 

 its past history. We have, however, a tolerable acquaint- 

 ance with the two higher groups — mammalia and birds, 

 both of Borneo and of all the surrounding countries, and 

 to these alone will it be necessary to refer in any detail. 

 The most convenient course, and that which will make the 

 subject easiest for the reader, will be to give, first, a 

 connected sketch of what is known of the zoology of 

 Borneo itself, with the main conclusions to which they 

 point ; and then to discuss the mutual relations of some of 



