a4 A FOSSIL CONTINENT 



their collateral dcsccndanta in Europe and Asia and America 

 or elsewhere went on progressing into far hit,'her, stronger, 

 and better adapted forms— the great central mammalian 

 fauna. In place of the petty phalangers and pouched ant- 

 eaters of the oolitic period, our tertiary strata in the larger 

 continents show us a rapid and extraordinary development 

 of the mammalian race into monstrous creatures, some of 

 them now quite extinct, and some still holding their own 

 undisturbed in India, Africa, and the American prairies. 

 The palffiotherium and the deinoceras, the mastodon and 

 the mammoth, the huge giraffes and antelopes of sunnier 

 times, succeed to the ancestral kangaroos and wombats of 

 the secondary strata. Slowly the horses grow more horse- 

 like, the shadowy camel begins to camelise himself, the 

 buffaloes acquire the rudiments of horns, the deer branch 

 out by tentative steps into still more complicated and more 

 complicated antlers. Side by side with this wonderful out- 

 growth of the mammalian type, in the first plasticity of its 

 vigorous youth, the older marsupials die away one by one 

 in the geological record before the faces of their more 

 successful competitors ; the new carnivores devour them 

 wholesale, the new ruminants eat up their pastures, the 

 new rodents outwit them in the modernised forests. At 

 last the pouched creatures all disappear utterly from all the 

 world, save only Australia, with the solitary exception of a 

 single advanced marsupial family, the familiar opossum of 

 plantation melodies. And the history of the opossum 

 himself is so very singular that it almost deserves to receive 

 the polite attention of a separate paragraph for its own 

 proper elucidation. 



For the opossums form the only members of the mar- 

 supial class now living outside Australia ; and yet, what is 

 at least equally remarkable, none of the opossums are 

 found ]^cr contra in Australia itself. They are, in fact, the 



