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which had been formerly organized, acquired a considerable polish, and 

 projected beyond the general surface, which was more rubbed down, 

 and which, although somewhat smoothed, had not obtained any polish. 

 The difference of the two substances was more accurately determined, 

 by immersing this same surface for a few minutes in marine acid, since 

 although a considerable degree of effervescence, and a removal of 

 some of the substance, evinced its action on the interposed lime-stone, 

 no trace of its influence on the polished projecting parts was discern- 

 ible ; even the polish was not in the least impaired. 



To what a remote period of past time, and to what astonishing 

 changes in the structure of the surface, at least, of this globe, does 

 this circumstance direct our contemplation ! A body, differing from 

 any animal substance now known, has been^formed, by the energies of 

 animal life, in the depths of the ocean of a former world ; and is now 

 found imbedded in a rock, many miles inland, and at a considerable 

 height above the sea : and these, wonderful as they are, are not the 

 only circumstances of this case, which, in the present state of our 

 knowledge, may be considered as inexplicable. The substance, of 

 which this body is composed, has undergone a most extraordinary 

 change : originally formed chiefly of carbonic acid and lime, with a 

 small portion of animal matter, it has now become a mass, in which, 

 except perhaps a portion of animal matter, these substances are no 

 longer to be found : the space which was formerly allotted to them 

 being now filled almost entirely with the earth of flint : and to add to 

 the wonder, the silicified mass is found imbedded in lime. 



In what situation this body was placed at the period it suffered this 

 change of its substance ? By what process its original constituent 

 principles were removed, and those of which it is now composed were 

 added, and how so great a change could be effected, with apparently no 

 alteration whatever of its form ? These are questions which perhaps 

 cannot be answered, until a considerable farther advance is made 

 . 



