chap, xin.] THE AUSTRALIAN REGION. 465 



few observations will therefore suffice, on the supposed early 

 history of the Australian region as a whole. 



It was probably far back in the Secondary period, that some 

 portion of the Australian region was in actual connection with 

 the northern continent, and became stocked with ancestral forms 

 of Marsupials ; but from that time till now there seems to have 

 been no further land connection, and the Australian lands have 

 thenceforward gone on developing the Marsupial and Monotre- 

 mate types, into the various living and extinct races we now find 

 there. During some portion of the Tertiary epoch Australia pro- 

 bably comprised much of its existing area, together with Papua 

 and the Solomon Islands, and perhaps extended as far east as the 

 Fiji Islands ; while it might also have had a considerable exten- 

 sion to the south and west. Some light has recently been thrown 

 on this subject by Professor McCoy's researches on the Palse- 

 ontology of Victoria. He finds abundant marine fossils of 

 Eocene and Miocene age, many of which are strikingly similar 

 to those of Europe at the same period. Among these are Ceta- 

 ceans of the genus Squalodon ; European species of Plagiostom- 

 ous fishes ; mollusca and corals closely resembling those of 

 Europe and North America of the same age, — such as numerous 

 Volutes closely allied to those of the Eocene beds of the Isle of 

 Wight, and the genus Dentalium in great abundance, almost or 

 quite identical with European tertiary species. Along with 

 these, are found some living species, but always such as now 

 live farther north in tropical seas. The Cretaceous and Meso- 

 zoic marine fossils are equally close to those of Europe. 



The whole of these remains demonstrate that, as in the 

 northern so in the southern hemisphere, a much warmer climate 

 prevailed in the Eocene and Miocene periods than at the present 

 time. This is a most important result, and one which strongly 

 supports Mr. Belt's view, before referred to, that the warmer 

 climates in past geological epochs, and especially that of the 

 Miocene as compared with our own, was caused by a diminution of 

 the obliquity of the ecliptic, leading to a much greater uniformity 

 of the seasons for a considerable distance from the equator, and 

 greatly reducing the polar area within which the sun would ever 



