392 FOSSIL FISH. 



In the Vivarrais, at a league from Privas, a department of the 

 Ardeche, on one side of a mountain, are found impressions of 

 skeletons, and skeletons themselves, of fossil fish of a single 

 species, in a marly, fissile, greyish earth, so light that it will 

 float in water, and situated below more than two hundred feet 

 of different kinds of lavas, which are surmounted by vast ba- 

 saltic causeways. Fossil fish are known which come from the 

 environs of Cadiz, and which are contained in a fissile marl, 

 extremely light, a little partaking of steatite. They have even 

 been found in China, according to the testimony of Lebrun ; 

 in Bohemia; in Nottingham, and other parts of England, in 

 certain quarries. They have also been found at Saarbruck, in 

 the upper part of the formation of pit-coal, and also in the 

 coal-mines of this country. 



At Elve, near Villefranche, a department of the Aveyron, 

 ichthyolites have been found in a limestone containing many 

 fossil shells. The geological affinities of this rock are not 

 known. It is a hard, marly, bituminous limestone, by no 

 means schistose, but very fetid. The place where the fish is 

 found is bluish, and forms a sort of globule surrounded with 

 white. 



M. C. Prevost found the head of a fish, in a fossil state, 

 near Villers-sur-Mer, in Normandy, in a bluish marly lime- 

 stone, which, in its geological position, corresponds to the 

 upper lias of our geologists, and to the middle layers of the 

 limestone of Jura of the French. It is this formation, as we 

 have before had much occasion to notice, which yields such 

 immense quantities of remains of ichthyosaurus. Near 

 Caen, also, in a stratum of the same character, M. de Magne- 

 ville found an ichthyolite apparently of the same species as 

 one found in aur lias by M. de la B^che, and called by him 

 Dapedium, 



We are very far indeed from having given a complete enu- 

 meration of the different localities in which ichthyolites have 

 been found. To do so would be impossible within the limits 

 to which we are of necessity confined. Imperfect, however, 



