172 



ing to the characteristic vegetable productions of 

 each the region of vines, of laurels, of pines, of 

 brooms, and of grapes. 



Now, if we picture to ourselves the first in- 

 habited district of the earth to have been a long 

 range of elevated continent, surrounded with 

 islands, we can easily understand how all kinds 

 of animals, as well as vegetables, may at one 

 time have lived, and moved, and had their being 

 on almost the same spot ; and, independently of 

 the subsequent migrations of the former, if we 

 call to mind that great changes, whether occur- 

 ing at once or at successive periods, may have 

 broken up and separated this primeval continent, 

 with its accompanying islands, we shall not be 

 at a loss to imagine how a dispersion, and sepa- 

 ration, and a distinct grouping of the animal 

 kingdom may have taken place. But to aid this 

 dispersion of animals, we have in addition their 

 migratory propensities. A great proportion of 

 animated beings have the power of loco -mo- 

 tion ; some, as quadrupeds, as I have shewn in 

 another place, in a considerable degree, and 

 others, as birds, fishes and insects, to an extent 

 which may embrace the whole circuit of the 

 globe. It is true, we cannot ascribe to quadru- 

 peds the power of traversing oceans by their own 

 unassisted resources, in the same manner as the 

 winged tribes are known to do, and thus of colo- 

 nizing the new world from the old, provided the 

 relations between the two had always been the 

 same as at present. But there is every reason 



