FOSSIL INVERTEBRATED ANIMALS. 457 



trse, selenes, bound together with a coarse and quartzose sand. 

 These shells can scarcely be said to differ in any respect from 

 those of the same species which came from the same forma- 

 tion in our own parts of the world. 



In North Carolina are found naticse, large pernae (perna 

 maxillata), venericardise, pectines, and other shells, which 

 have many relations with similar species which have been met 

 with in the Placentine. These shells are free, filled with a 

 yellow quartzose sand, and seem to depend on the coarse 

 limestone, or on other formations less ancient than the chalk. 

 But M. de France states, that he has never seen any fossil 

 from America which exhibits any relations to the strata of the 

 last-mentioned formation. 



In the coarse limestone, which is certainly a marine deposi- 

 tion, shells are to be found, whose genera are no longer in 

 existence, except in the fresh water : — such are the ampullarise, 

 the melaniae, and the cyclostomata. These genera, too, with 

 the exception of the last, are found, at the present day, only 

 in chmates warmer than our own. Indeed, respecting the 

 subject of climate, in relation to fossils, every thing is calculated 

 to excite astonishment, and nothing admits of explanation. 

 The case is very nearly the same, in relation to the genera 

 which formerly inhabited the sea, and which are no longer 

 found except in fresh waters, unless we admit a difference in 

 the degree of saltness in the former. This, indeed, must be 

 more considerable at present, than it was before the number of 

 ages, since the sea occupied our continents, had elapsed ; — 

 during which, the rivers and streams have been, and still are, 

 incessantly supplying it with saline particles, which it receives 

 to return no more. But, if we admit that the sea, having been 

 less saline, might have allowed of the existence of certain 

 genera in its waters, in former days, but which can exist there 

 no longer, we must also admit that such genera as live there 

 in the present day, and which lived there at the era in which 

 the coarse limestone was formed, have been enabled to support 



