I III: AUSTRALIAN REGION 35 



Section VI. — Past History of the Mammal- 

 fauna of the Austral Sub-region 



The past history of the Australian nianiinals is still 

 very obscure ; the only remains of extinct species yet 

 discovered have been found in certain bone-caves and 

 in surface-deposits generally attributed to the Pleistocene 

 Epoch. 



Putting aside the Dingo, all the Pleistocene mammals 

 of Australia belong to the Monotremes or to the Mar- 

 supials, and, with two exceptions, can be accommodated 

 in still existing families. These exceptions are Noto- 

 t/trriiun and Diprotodon, the latter of which was a very 

 Large animal, equalling a Rhinoceros in bulk, but both of 

 them were probably allied to the existing Kangaroos. 



Recently a deposit containing bones of these and other 

 large Marsupials has been found in a dry salt lagoon, 

 called Lake Mulligan, in South Australia, and when these 

 remains have been worked out, a great deal more informa- 

 tion as regards this pliocene or pleistocene fauna may be 

 expected. As in South America, these extinct animals 

 appear in many cases to have attained a size far surpassing 

 that of their degenerate descendants. 



None of the remains hitherto found in Australia 

 throw much light on the origin of its remarkable fauna. 

 But quite recently evidence of an extensive mammalian 

 fauna has been discovered in certain beds, of probably 

 Upper Eocene age, in Santa Cruz, Patagonia. In addition 

 to a number of other forms, this series contains the re- 

 mains of many Marsupials, and though the most promi- 

 nent of them belong to the Didelphyidse — the Marsupial 



