Physical Geography. 21 



a similar shallow sea connected New Guinea and some of the 

 adjacent islands to Australia, all being characterized by the 

 presence of Marsupials. 



We have here a clew to the most radical contrast in the 

 Archipelago, and, by following it out in detail, I have arrived 

 at the conclusion that we can draw a line among the islands, 

 which shall so divide them that one-half shall truly belong to 

 Asia, while the other shall no less certainly be allied to Aus- 

 tralia. I term these respectively the Indo-Malayan, and the 

 Austro-Malayan divisions of the Archipelago. {See Physical 

 Map.) 



On referring to pages 12, 13, and 36 of Mr. Earl's pam- 

 phlet, it will be seen that he maintains the former connection 

 of Asia and Australia as an important part of his view, whereas 

 I dwell mainly on their long continued separation. Notwith- 

 standing this and other important differences between ns, to 

 him undoubtedly belongs the merit of first indicating the di- 

 vision of the Archipelago into an Australian and an Asiatic 

 region, which it has been my good-fortune to establish by 

 more detailed observations. 



Contrasts in Natural Productions. — To understand the im- 

 portance of this class of facts, and its bearing upon the former 

 distribution of land and sea, it is necessary to consider the re- 

 sults arrived at by geologists and naturalists in other parts of 

 the world. 



It is now generally admitted that the present distribution 

 of living things on the surface of the earth is mainly the result 

 of the last series of changes that it has undergone. Geology 

 teaches us that the surface of the land and the distribution 

 of land and water is everywhere slowly changing. It further 

 teaches us that the forms of life which inhabit that surface 

 have, during every period of which Ave jDossess any record, 

 been also slowly changing. 



It is not now necessary to say any thing about how either 

 of those changes took place ; as to that, opinions may differ ; 

 but as to the fact that the changes themselves have occurred, 

 from the earliest geological ages down to the present day, 

 and are still going on, there is no difference of opinion. 

 Every successive stratum of sedimentary rock, sand, or gravel 

 is a proof that changes of level have taken place ; and the dif- 



