MOLLUSCA. 243 



another, as the recent kinds are known to do, so that every 

 country will have its fossil, as well as its recent testacea. 

 Few observations illustrative of this branch of the subject 

 have hitherto been published. 



It has often been remarked, that the fossil shells (and the 

 relics of other animals and plants) found in the strata of this 

 country, are very different in their appearance from those 

 shells of the mollusca which at present exist in the country, 

 but that they bear a close resemblance to the" existing 

 species of the equatorial regions. This very important ob- 

 servation has led some to conclude, that the mollusca which 

 lived in this country at the period of the formation of the 

 strata in which they are now enclosed, were influenced by 

 different physical circumstances, from those by which the 

 forms of the recent kinds are regulated ; while others have 

 imagined that those shells once lived in the equatorial re- 

 gions, and that a mighty deluge transported them to their 

 present situation. This last conclusion can never be ad- 

 mitted by those who have witnessed the perfect preservation 

 of the different parts of fossil shells, their valves, spires, 

 protuberances, and delicate spines, still unbroken. Though 

 these species no longer exist in a living state in this coun- 

 try, nor on the globe, we must admit the conclusion of 

 Werner, with regard to fossil plants, that they lived and 

 died in the country where their relics are now found. 



It would form a very curious subject of inquiry to ascer- 

 tain the character of those fossil shells which are found k in 

 the strata near the equator. If they likewise differ from 

 the recent species of those seas, and if, in appearance, they 

 resemble or differ from the productions of arctic regions, we 

 might then speculate, with more success, upon those mighty 

 revolutions which have taken place on the earth's surface, 



