286 



stance, and the filling up of the interstices with the lapidifying 

 matter. 



But it still remained to determine if a correspondent organic mat- 

 ter existed in animal fossils. To ascertain this point, therefore, the va- 

 rious kinds of animal fossils noticed in this volume, were subjected to 

 a chemical examination, by which the most satisfactory proofs were 

 obtained of the existence of this animal matter, and even of its re- 

 taining, in several instances, very much of its original form. 



This circumstance was beautifully illustrated by the examination of 

 an entrochus of the lily encrinite, the particulars of which are men- 

 tioned, page 166, and are illustrated by the engraving, Plate XIII. 

 Fig. 47- A similar examination of the fossil tubipore, Plate I. Fig. 1, 

 was equally successful ; the animal membrane belonging to the 

 coral, from which the marble derived its origin, being rendered ex- 

 ceedingly evident Indeed, in a subsequent examination of this mar- 

 ble, the success was far beyond expectation ; the animal membrane 

 was displayed, retaining the general external form, with the original 

 colour of the coral. The experiment was performed with equal suc- 

 cess with several other substances ; particularly with a piece of the 

 Derbyshire entrochal marble, the animal membrane of which was 

 rendered perfectly distinct. 



Other experiments have already convinced me, that the presence of 

 organic matter in animal fossils, of almost every kind, is sufficiently 

 frequent to authorize, in the fullest manner, the opinion which I have 

 already advanced, respecting the principles on which the process 9f 

 petrifaction" is accomplished. In the vegetable fossils, it is true, that 

 the organic matter appears to have undergone a particular change, 

 having been previously brought to the state of bitumen ; and I have 

 strong reasons, the result of actual observation, for believing that, 

 in the animal fossils, a correspondent change has been previously in- 

 duced; and that the animal matter has suffered a conversion into 

 adipocire. 



