Theoretical Considerations. 401 



in some portions of the sedimentary rock, the necessary ingredients 

 for the production of feldspar were wanting. In the same manner, 

 the quartz rock associated with the gneiss, might have proceeded from 

 a sandstone composed chiefly of siliceous sand. 



According to this view of the subject, granite, and perhaps other 

 primary rocks, must have existed anterior to those which now form 

 the crust of the globe ; and from the detritus of which, the existing 

 primary rocks were produced; being subsequently indurated and 

 crystalized by a new eruption of granite and other unstratified rocks. 

 Thus we trace a number of successive epochs of renewal and destruc- 

 tion, before the earth assumed its present form : and now we see the 

 process of destruction going forward. To these changes the mathe- 

 matician who first developed the fundamental principles of this theory 

 saw no marks of a commencement, no prospect of an end ; and 

 hence he has been supposed to defend the hypothesis of the world's 

 eternity, and to exclude a Deity from its creation and government. 

 But surely his own theory did not teach him that the earth had exist- 

 ed in more than two states anterior to the present ; viz. the state that 

 preceded the existence of our present primary strata, and that which 

 included these only. And had he been acquainted with the history of 

 organic remains, as the subject is now understood, he might have 

 known that there is no proof of more than five or six extinctions of 

 animals and plants antecedent to the creation of the present races; and 

 still farther, he might have known that each successive creation exhib- 

 ited a greater degree of perfection in animal natures ; thus proving 

 a progressive state of things ; which implies a commencement. And 

 the whole history of the rock strata shows a corresponding improve- 

 ment in the state of the globe, pointing us back to an original begin- 

 ning. Further, had this philosopher been as well acquainted with 

 the chemistry of nature as with her mathematics, he must have 

 known, that an intensely heated globe could not have existed eternally 

 in that state ; andthat as there must ha\e been a period when it began, 

 so there will be a period when it will cease to radiate heat ; and, there- 

 fore, the fundamental principle of his theory should have taught him, 

 that probably the world had a beginning, and will have an end. In- 

 deed if I understand geology aright, so far from teaching the eternity 

 of the world, it proves more directly than any other science can, that its 

 revolutions and races of inhabitants had a commencement, and that it 

 contains within itself the chemical energies, which need only to be set at 

 liberty by the will of their Creator, to accomplish its destruction. Be- 

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