THEORY OF THE EARTH. 433 



In tbc early-portions of the "primary" strata, there 

 are limestones in considerable quantity, and therefore 

 formed under the ocean of the second terraqueous, or 

 fifth earth. In the later, there are organic animal re- 

 mains in abundance ; whence that Earth was assu- 

 redly inhabited, during at least its later periods. I 

 must presume, that it was thus inhabited at as .early a 

 period after its change as it could have been ; partly 

 in consistency with what I have already said, and partly 

 because, having demonstrated that it is the effect of 

 heat to obliterate organic remains in limestone, and 

 that the earlier primary strata have been especially 

 under its action, their absence forms no objection. 

 Thus also does the absence of such bodies from still 

 earlier strata, cease to be a difficulty ; as these facts 

 render the present theoretical view of the origin of 

 limestone more probable. And in further support of 

 such a view, let it also be remarked, that as the organic 

 creation necessarily increases during any period of re- 

 pose in the earth, so is it true that the limestones aug- 

 ment in proportion as we ascend in the order of these 

 primary strata ; as the organic bodies also remain 

 where the heat must have been least. I need only here 

 refer to some former facts respecting the existence of 

 organic animal fragments in even the earlier primary 

 strata: and thus also, from analogous ones respecting 

 primary coal, content myself with simply inferring 

 some vegetable creation. Whether this was marine 

 only, or terrestrial also, will never now be known : but 

 under the preceding metaphysical argument, I can 

 never believe that there was a dry land, covered with 

 alluvia and soil, as it must have been under degrada- 

 tion, which was not occupied by plants at least. If it 

 possessed terrestrial animals, they could not have been 

 preserved, as I formerly showed ; so that this negative 



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