292 Mr. Lyell on the Freshwater Strata of Hordwell Cliff, S^c. 



individuals are in great abundance, is a circumstance characteristic of recent 

 freshwater deposits : whereas shells, whenever they occur plentifully in ancient 

 marine formations, belong- to a variety of distinct species ; and, from what we 

 know of the living testacea of our seas, we may conclude that this is the case 

 in submarine strata now in the act of forming. The almost entire absence, 

 amid such a multitude of organic remains, of decided marine productions, is, 

 when coupled with the other circumstances, a strong negative fact. Upon the 

 whole, there are sound geological reasons, both in this and in other instances^ 

 for extending the term Freshwater Formations to deposits which may have 

 been formed at the mouths of rivers, and for no longer restricting it to such 

 as have originated in inland lakes. 



