28 The Philippine Journal of Science im 



that Palawan has been submerged and most or all of its vegetation 

 destroyed since the existence of its earlier connection with the 

 Philippines by which our dipterocarps and numerous other west- 

 ern Malaysian types in all probability reached the Philippines 

 (see p. 8) ; whatever the case, the Palawan-Calamian group 

 has been severed from the Philippines proper by the Min- 

 doro Strait since Pleistocene times, and received much of its 

 present fauna from Borneo in the middle or late Pleistocene. 

 At the same time it has also received certain very definite 

 Bornean elements of its flora that have failed to reach the 

 Philippines proper, although its flora is by no means strictly 

 Bornean, but presents approximately as many Philippine ele- 

 ments as it does Bornean ones. In other words, its flora has 

 been derived in part from Borneo and in part from the Phil- 

 ippines proper. 



There must have been extensive and especially prolonged 

 connections between Borneo and the Philippines, but there is no 

 evidence that these connections were more than the Sulu and 

 Palawan isthmuses. It is highly improbable, although not 

 impossible, that some of our western Malaysian elements came 

 in from eastern Java over the Java-Celebes and the Celebes-Min- 

 danao bridges ; but, had there been any extensive migrations over 

 this route, we would naturally expect to find a much greater 

 mingling of Australian and Asiatic types in Celebes than actually 

 exists, with corresponding Australian types in Java. In the 

 Mindoro flora we find certain western Malaysian types that 

 extend from Borneo through Palawan to Mindoro but do not 

 occur farther east. We cannot ignore the fact that our one large 

 indigenous mammal, the timarao, is confined to Mindoro, and 

 that it must have been derived from Asiatic stock; it unques- 

 tionably reached Mindoro over the Palawan bridge. It is cur- 

 rently stated that the timarao is most closely allied to the anoa 

 of Celebes, but this seems not to be the case, as Doctor Hollister 

 informs me that the timarao is not congeneric with the anoa but 

 is congeneric with a form that occurs in Borneo. 

 CONCLUSIONS 



1. From the geologic and hydrographic data so admirably 

 presented by Molengraaff, it is perfectly evident that the geologic 

 history of eastern Malaysia has been radically different from that 

 of western Malaysia. The area approximately delimited by the 

 Asiatic continental shelf, which carries upon it all of the Sunda 

 Islands, was a continental area in the Pleistocene and probably 



