chap, i.] PHYSICAL GEOGRAPHY. 25 



the hot damp luxuriant forests which everywhere clothe 

 the plains and mountains of New Guinea. 



In order to illustrate more clearly the means by which 

 1 suppose this great contrast has been brought about, let 

 us consider what would occur if two strongly contrasted 

 divisions of the earth were, by natural means, brought 

 into proximity. No two parts of the world differ so 

 radically in their productions as Asia and Australia, but 

 the difference between Africa and South America is also 

 very great, and these two regions will well serve to illus- 

 trate the question we are considering. On the one side 

 we have baboons, lions, elephants, buffaloes, and giraffes ; 

 on the other spider-monkeys, pumas, tapirs, ant-eaters, 

 and sloths ; while among birds, the hornbills, turacos, 

 orioles, and honeysuckers of Africa contrast strongly with 

 the toucans, macaws, chatterers, and humming-birds of 

 America. 



Now let us endeavour to imagine (what it is very 

 probable may occur in future ages) that a slow upheaval 

 of the bed of the Atlantic should take place, while at the 

 same time earthquake-shocks and volcanic action on the 

 land should cause increased volumes of sediment to be 

 poured down by the rivers, so that the two continents 

 should gradually spread out by the addition of newly- 

 formed lands, and thus reduce the Atlantic which now 

 separates them to an arm of the sea a few hundred miles 



