206 NATURAL EISTOEr [chai*. xiv 



The Timor group of isLauds contains : — 



Javan birtla . . . . • 36 Australian birds . , . 13 

 Closely alliiid Bp€cies , . 11 Closely allied spociea . . 35 



Derived from Java . . 47 Derived from Australia . 48 



We have here a wonderful agreement in the number of 

 biitia helongitig to Australian and Javanese groups, but 

 they are divided in exactly a reverse maimer, thi*ee-fom1:.hs 

 of the Javan birds being identical species and one-fourth 

 representatives, while only one-fourth of the AiistraUan 

 forms are identical and three-lburths representatives. Thi& 

 ia the most important fact which we can elicit from a 

 study of the buds of these islands, since it gives us a very' 

 complete clue to mueli of their past history. 



Change of species is a slow process. On that we are alt 

 agreed, though we may differ about how it has taken pltice. 

 The fact that the Australian species in these islands have 

 mostly changed, wliile the Javan species have almost all 

 remained imchanged, would tlierefore indicate that the 

 district was first peopled from Austraha. But, for this to 

 have been the case, the physical conditions must have been 

 very different from what they are now. Nearly tliree 

 lumdred miles of open sea now separate Austnilia from 

 Timor, which island is connecttfd with Java by a cliaiii of 

 broken land divided by straits wdiich are nowhere more 

 than about twenty miles wide. Evidently there are now 

 great facilities for the natural productions of Java to 

 spread over and occupy the whole of these islands, while 

 those of Australia would find very great diliiculty in 

 getting across. To account for the present state of tilings, 

 we should naturally suppose that Australia was once much 

 more closely connected with Timor than it is at present ; 

 and that this w^as the case is rendered highly probable by 

 the fact of a submarine bank extendiug along all the north 

 and west coast of Australia, and at one i)lace approaching 

 witliin twenty miles of the coast of Timor. This indicates 

 a recent subsidence of North Australia, which probably 

 once extended as far as the edge of this bank, between 

 vhich and Timor there is an unlathomed depth of ocean. 



I do not think that Timor was ever actually connected 



