CHAP. I.] 



PHYSICAL GEOGRAPHT, 



17 



the toucans, macaws, chatterers, and liimiming-birda of 

 Aijierica. 



Now let us endeavour to imagine (wbat it is very 

 probable may occur in future ages) that a slo\7 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 inci-eased volumes of sediment to he 

 pouiied 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 tlie sea a few hundred miles 

 wide. At the same time we may suppose islands to be 

 upheaved in mid-channel ; and, as the subterranean forces 

 varied in intensity, and shifted their points of greatest 

 action, these islands would sometimes become connected 

 with the land on one side or other of the strait, and at 

 other times again be separated from it. Several islands 

 would at one time be joined together, at another "would be 

 broken up again, till at last, after many long ages of such 

 intermittent action, we might have an irregular arcliipelago 

 of islands fiUiug up the ocean channel of the Atlantic, in 

 whose appearance and arrangement we could discover 

 tiothuig to tell us which had been connected with Africa 

 and which with America. The animals and plants in- 

 liabiting these islands would, however, certainly reveal 

 this portion of their former liistory. On those Islands 

 which had ever formed a part of the South American 

 continent we sliobld be sure to find such common birds 

 as chatterers and toucans and humming-birds, and some 

 of the i>eculiar American quadrupetls ; while on those 

 which had l)een separated from Africa, hombills, orioles, 

 and honeysuckers would as certainly be found. Some 

 portion of the uprui^ied laml might at different times have 

 had a temporary connexion with both continents, and 

 would then contain a certain amount of mixture in its 

 U^dng inhabitants. Such seems to have been the case 

 with the islands of Celebes and the Philippmes. Other 

 islands, again, though in such close proximily as Bali and 

 I^mbock, might each exhibit an almost unmixed sample 

 of the productions of the continents of which they bad 

 diiectly or iudirectly once formed a part. 



c 



