470 FOSSIL INVERTEBRATED ANIMALS. 



certain M. le Royer de la Sauvagere, who, assisted by his 

 vassals and his neighbours, had twice witnessed, in the space 

 of four-and-twenty years, a part of the soil of the environs of 

 his estate of Desplaces, in Touraine, metamorphosed into a 

 bed of tender stone. The shells seen there were at first so 

 small, that they could not be discerned without the assistance 

 of a microscope ; but afterwards they increased with the stone, 

 so as to assume, by invisible degrees, ten lines in thickness. 

 If, however, we set aside this observation, and pay attention 

 to those of more practised naturalists than M. le Royer de la 

 Sauvagere, we may say that the present formation of petrifac- 

 tions, at least in the interior of the earth, is not established on 

 any positive fact, and that simple reason does not warrant the 

 affirmative of this part of the question. In the bosom of the 

 waters, however, such an operation may take place ; for it ap- 

 pears, that the immersion of bodies in a fluid, dissolving the 

 matter which petrifies, is a necessary condition to the petri- 

 faction. 



A great number of petrifactions being siliceous, the fluid in 

 which they have been found must have had the property of 

 dissolving the silex. Now, we are acquainted with no fluid, at 

 present in abundance in nature, which possesses this property. 

 The same may be said of solvents of carbonates, fluates, or 

 phosphates, which are also equally unknown *. 



Two facts only seem to prove the possibility of the recent 

 formation of fossils. The first is, that many travellers, who 

 have examined the coasts of New Holland, have seen, in dif- 

 ferent parts, some very curious and singular petrifactions. 

 Riche, in the bay which the French call De I'Esp^rance, hav- 

 ing penetrated into a valley sunk between downs of sand, found 

 it covered with calcareous trunks of trees, broken towards the 

 root, and the stumps of which, standing upright, were not 



* We have merely heard of certain hot waters containing potash in 

 solution, which had the property of dissolving silex, and which deposited 

 stalactites of chalcedony. 



