98 THEORY OF THE EARTH. 



Confusedly, and almost always broken and reduced 

 to fragments, which are the only means left to 

 naturalists for ascertaining the species or genera to 

 which they have belonged. 



It may be stated also, that most observers, alarm- 

 ed by these formidable difficulties, have passed 

 slightly over the foeeil remains of quadrupeds, and 

 iiave satisfied themselves with classing them vague- 

 ly, by means of slight resemblances, or have not 

 even pretended to give them names. Hence this 

 portion of the history of extraneous fossils, though 

 the most important and most instructive, has been 

 investigated with less care than any other.* 



Fortunately, comparative anatomy, when tho- 

 roughly understood, enables us to surmount all 

 these difficulties, as a careful application of its 

 principles instructs us in the correspondence and 

 dissimilarity of the forms of organized bodies of 

 different kinds, by which "each may be rigorously 

 ascertained, from almost every fragment of its va- 

 rious parts and organs. 



Every organized individual forms an entire sys- 



*AsI have already remarked on a former occasion, it is not my 

 intention, by these observations, to detract from the merits of Cam- 

 per, Pallas, Blumenbach, Scemmering, Merk, Faujas, Rosenmuller, 

 and other naturalists, in regard to extraneous fossils : But, though 

 their observations have been of great value in my researches, and are 

 quoted by me hi every stop, they are in general very incomplete. 



."*; <. ..- 



*... 





