554 [Feb. 26. 



Soleii ensis Lin. Williamsburg and Wihnijigton. 

 Panopoea Americana. Maryland and Petersburg. 



Same as P. Aldrovandi. 

 Mactra lateralis Say. Petersburg. 



Same as M. simUis. 

 Liicina divaricata Lam. Williamsburg, Maryland ; and Petersburg. 



Identical with a West Indian variety. 

 L. anodonta Say. Evergreen, Virginia ; and Wilmington, North Carolina. 

 L. squamosa. Petersburg. 



L. contracta Say. Wilmington, North Carolina ; and Williamsburg, Mary- 

 land. 



It appears to be the same as L. radula. 

 Astarte lunulata Con. Williamsburg. 



Identical with a recent shell from South Carolina. 

 Venus mercenaria Lam. Wilmington, North Carolina. 

 Nucula limatula Say. Petersburg. 

 N. proxima Say. Williamsburg. 



Identical with recent specimens on the coast of Massachusetts, 

 Modiola glandula Totten. Petersburg. 



Identical with a recent specimen from Massachusetts. 

 Pecten magellanicus Lam. Petersburg. 



The above list would give a proportion of about 17 per cent, of 

 recent species, or about one-sixth ; but I have no doubt that if we 

 possessed in London larger collections of the shells now inhabiting 

 the American seas, I should be able to prove that a greater number 

 of them agreed with fossils of the miocene strata in the United 

 States. Thus I have not included Anomia ephippium, because the 

 specific characters in this genus are so unsatisfactory ; and I have 

 not seen the recent shell which Mr. Conrad identifies with Lucina 

 crenulata ; nor have I been able to identify Artemis acetabulum, 

 given as a recent species by Mr. Conrad, which does not agree 

 with A. concentrica Lam., nor with the species which inhabits the 

 Pacific coast of South America. 



The general resemblance of the American fossils of this era with 

 those of the Suffolk crag and faluns of the Loire was so great, that 

 I was surprised, on a closer comparison, to find that I could only 

 identify 9 species as common to both sides of the Atlantic, and that 

 out of 147 American fossils, I could only find 13 species in the 

 European miocene, which were so closely allied as to be entitled 

 to be regarded as geographical representatives. A great part, 

 therefore, of the analogy consists in the similarity of the genera. 



List of Species common to the American and European Miocene 



Strata. 



1. Fusus rostratus Dujardin. 



Found by me at Burwell's Mill, Williamsburg, Maryland ; and agreeing 

 with a common fossil of the faluns of Touraine. 



2. Purpura lapillus Lin. Petersburg, Virginia. 



American variety : probably the same species as P. crispata of the red 

 crag, Suffolk, some varieties of which agree with the European P. lapillus. 



3. Turritella plebeia Say. Maryland. 



This agrees perfectly with an abundant fossil of the Touraine faluns, to 

 which Dujardin has given the name, incorrectly perhaps, of T. Linnaa. 



