550 



THE AMERICAN NATURALIST [Vol. XL V 



Australia as that of Sumatra, Borneo and Java lias de- 

 rived from the mainland of Asia. 



A general survey of all conditions leads to the conclu- 

 sion that in post-Cretacean times there was a broad con- 

 nection between the three Greater Sunda Islands and 

 Asia on the one baud, and between Xew Guinea and Aus- 

 tralia upon the other; that further also between the 

 Sunda Islands and Xew Guinea a connection must have 

 existed which was really less easy to pass over. The con- 

 figuration of the bottom of the ocean supports this opin- 

 ion. The western half of the archipelago is united with 

 Asia, standing on a plateau of not more than fifty fathoms 

 depth; Xew Guinea is separated from Australia by a 

 similarly shallow sea. An elevation of the sea bottom 

 of 45 meters would connect the Greater Sunda Islands 

 with the mainland of Asia ; while on the other hand a rise 

 of 20 meters is all that is necessary to bring about the 

 joining of Xew Guinea with Australia. The seas inter- 

 vening between these two regions have, on the contrary, 

 for the most part a great depth. 



There still remains much to do in substantiation of the 

 proof of these conclusions; and the islands and island 

 groups of the archipelago are still a fruitful field of in- 

 quiry for those who may be interested. 



lie upon a shallow submarine pint can which hinds them to 

 further India. Upon this same plateau lie also a host of 

 lesser islands such as Banca and Billeton, Madura and 

 Bali. All of these islands, as well as those which lie along 

 the west coast of Sumatra, and which are surrounded by a 

 sea of considerably greater depth, possess a fauna which 

 in all its principal characteristics is essentially that of the 

 Malay Peninsula. Here alone one finds the great Indian 

 mammals, such as the Orang Utan, the tiger, the leopard, 

 the Malayan hear, elephant, tapir, rhinoceros and bantang. 

 Even still more evident is the relationship of the mainland 

 when one takes into account the finds among the fossils. 

 Dubois lias uncovered a Tertiary fauna upon Java that 

 bears the most marked resemblance to the Pliocene Siwalik 



