NATURAL HISTORY OF CREATION. 195 



World, is not much different fi-om saying tlia*: tlie 

 rasorial type is there peculiarly abundant. It should 

 not escape notice that, if it shall be proved that there 

 are detached lines of progress, that these were iso'a'cd in 

 different regions of the earth, and yet the succession of 

 beings was the same in each, as far, at least, as classes 

 and orders are concerned, we shall be furnished with one 

 of the most pow^erf ul proofs of design or pre-arrangement 

 that could be imagined. It does not appear that the 

 idea of independent lines, consisting of particular types, 

 or sets of types, is necessarily inconsistent with the 

 general hypothesis, as nothing yet ascertained of the 

 Macleay system forbids their ha\'ing an independent set 

 of affinities. On this subject, however, there is as yet 

 much obscurity, and it must be left to future inquirers 

 to clear it up. 



We must now call to mind that the geographical dis- 

 tribution of plants and animals was very difterent in the 

 geological ages from what it is now, Down to a time 

 not long antecedent to man, the same vegetation over- 

 spread every clime, and a similar uniformity marked the 

 zoology. This is conceived by M. Brogniart, wdth great 

 plausibility, to have been the result of a uniformity of 

 climate, produced by the as yet unexhausted effect of the 

 internal heat of the earth upon its surface; whereas 

 climate has since depended chiefly on external sources of 

 heat, as modified by the various meteorological influences. 

 However the early uniform climate was produced, 

 certain it is that, from about the close of the geological 

 epoch, plants and animals have been dispersed over the 

 globe with a regard to their particular characters, and 

 specimens of both are found so isolated in particular 

 situations, as utterly to exclude the idea that they came 

 thither from any common centre. It may Ijc asked — 



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