ZOOGEOGRAPHY. 153 



(if it was ever actually joined) from Australia very early; and the great develop- 

 ment of peculiar species of birds, insects, etc., is of later date. The real diffi- 

 culty is to account for such large provinces so near to one another being so dis- 

 tinct, not to account for a few forms getting across the narrow passage." 



Muir continues by saying that he could adduce very many facts against a 

 recent connection between the two provinces. It is interesting to see how closely 

 his views, based upon field observations and his studies on insects, agree with 

 my own, based upon the studies of other animals. This two-fold origin of the 

 present Australian fauna certainly seems reasonable enough. I can not, how- 

 ever, agree with Muir in believing that the connection between Papua and 

 Queensland did not persist until after east and west Australia had joined together. 

 That a change of climate, such as Muir suggests, would tend to destroy the 

 Malayan fauna in southern Australia if it reduced the rainfall, is quite certain. 

 It seems, however, more reasonable to assume that the part of Australia so long 

 connected with New Guinea was in reality rather Umited; and that some of the 

 Malayan forms, left isolated in this region, have spread to other favorable areas 

 in the land to which the Cape York region joined. A large proportion of Papuan 

 species in Australia would seem, from what we know of their kindred elsewhere, 

 to be perfectly well able to adapt themselves to somewhat changed conditions; 

 yet they are entirely confined to this Cape York region. It is unlikely that they 

 formerly had a great range in eastern Australia. 



That Suess inclines to an opinion very like that of Muir is proved by the 

 following quotation (4, p. 292) : — 



"The Cordillera [of Eastern Austraha] is continued, according to Haddon, 

 SoUas, and Cole, in islands, formed chiefly of granite, from York Peninsula across 

 Torres Straits, and it terminates on the margin of the great southern plain of New 

 Guinea in the granite hill of Mabudauan." He continues, "The succession of 

 marine strata in Australia presents many more gaps in the Mesozoic series than 

 that of Timor, New Caledonia, or New Zealand. The Cretaceous system, * * * 

 extends over broad Archaean regions; according to recent observations the 

 desert sandstone is assigned to it." 



The statement that the shallow sinking which took place to form the present 

 Torres Straits occurred Init shortly after the changes of level in Australia itself, 

 is supported by the fact that the Solomon Islands and the New Hebrides have a 

 strongly marked Papuan fauna, while typical Australian forms are very rare there. 

 This is also the condition as far as New Zealand, where this connection with 

 Papuasia and isolation from Australia is probably emphasized even by the migra- 



