278 EXPLORATION OF THE CAVES OF BORNEO. 



Sarawak caves, at least to a height of many hundred feet, will 

 prove equally recent, and for the following reason : The contents 

 of the Sarawak caves must have been accumulated since the date 

 of the last submergence of north-west Borneo, unless the subsi- 

 dence of the land was very trifling indeed. But the submergence 

 actually went on to a depth of 500 feet, and probably much more, 

 as is abundantly evidenced by the indications of purely marine 

 denudation on the inland hills ; and that it was very recent in a 

 geological sense, may with fairness be deduced, I think, from the 

 slight amount of differentiation which the present Fauna of the 

 island has undergone since its last connection with continental 

 Asia, coupled with the rapid rate at which the Sarawak coast is 

 even now advancing seaward, which argues that the tract of land 

 now intervening between the sea and the limestone hills cannot be 

 of much antiquity. The absence of any heavy floors of crystalline 

 stalagmite in the caves seems to add confirmatory testimony in 

 this direction, as does, perhaps, the absence of the large mammals 

 of Borneo (elephant, rhinoceros, tapir, and wild ox), from the 

 north-west districts. It may be worth remarking, that all the 

 tribes of Land Dyaks have most circumstantial traditions current 

 among them on the subject of a great subsidence of the land. 



With' regard to the rate of accumulation of the cave-deposits 

 in Sarawak, it seems probable that it would be in excess of that 

 generally observable in the case of other countries, for the rocks 

 are of an extremely decomposable class, and, as I have noted above, 

 the rainfall is prodigious. 



"With respect to the possible future discovery of ossiferous 

 deposits other than those mentioned above, I think it probable 

 that such will be found. They cannot, however, be very numerous 

 in proportion to the number of caves. The natives have been in 

 the habit for many years past of excavating the contents of the 

 caves and fissures for the purpose of washing out the alluvial gold 

 they afford. The caves examined in this way are situated at all 

 elevations up to 100 feet. Both Malays and Chinese set a value 

 on fossil teeth, which they preserve as charms or use for medicinal 

 purposes ; nevertheless, they have never met with a regular ossi- 

 ferous deposit in the course of their explorations. Had they done 

 so, it would have been certain to attract their attention. Bones 



