THEORY OF THE EAUTH. 



Plan of this Essay. 



W : HAT I especially propose to present in this 

 discourse, is the plan and the result of my lahours 

 regarding Fossil Bones. I shall also attempt to 

 trace a rapid sketch of the efforts that have heen 

 made up to the present day, to restore the history 

 of the revolutions of the glohe. The facts which 

 I have been enabled to discover, form, without 

 doubt, only a small portion of those which would 

 be necessary to complete this ancient history ; but 

 several of them lead to decisive consequences, and 

 the rigorous manner in which I have proceeded in 

 their determination, affords me reason to think 

 that they will be regarded as points definitively 

 fixed, and which in their aggregate will form an 

 epoch in science. Lastly, I trust their novelty 

 will be a sufficient excuse for me, if I claim for 

 them the earnest attention of my readers. 



My object will first be to shew by what rela- 

 tions the history of the fossil bones of terrestrial 

 animals connects itself with the theory of the 

 earth, and for what reasons a peculiar importance 

 is to be attributed to it, with reference to this 

 subject. I shall then unfold the principles upon 

 which is founded the art of determining these 

 bones, or, in other words, of recognizing a genus, 

 and of distinguishing a species, by a single frag- 

 ment of bone, an art, on the certainty of which 



