214 



THE GEOLOGIST. 



impalpable siliceous powder derived from the cases of infusorise. It 

 rests on eocene strata of greenish sand, and is overlaid by miocene clays 

 containing Artemis acetabulum, &c. ; and it has been referred by Professor 

 W. Rogers to the former epoch. A similar tertiary green sand occurs 

 at Petersburg, thirty miles south of Richmond, and contains a Vene- 

 ricardium and an Ostrea, undistinguishable from V. planicosta and 

 0. bellovicina. It is there also covered by miocene marls, which yield a 

 rich series of fossils distinct from those of the sub-adjacent sands, but 

 bearing a great resemblance to series from the Suffolk crag and the 

 faluns of Touraine, several species of Virginia testacea, Crustacea, 

 echinodermata, &c. being very analogous to crag and Touraine fossils ; 

 but the most important point is shown to be the correspondence which 

 exists in the proportion of recent to extinct species of shells, sixteen out 

 of eighty-two species being regarded by Mr. Conrad as identical with 

 recent shells, the greater part inhabiting the coasts of the United States. 

 This proportion of one-fifth agrees well, Mr. Lyell says, with the results 

 obtained by him in 1840, in different localities of the faluns of Touraine. 

 The total numher of American miocene shells known to Mr. Conrad is 

 238, of which 38 are recent. 



North Carolina. — Near South Washington, on a branch of Cape Fear 

 River, the author found, in the dark bluish marls of the cretaceous 

 series, previously noticed by Mr. Hodge in a paper on the Southern 

 States, several fossils, characteristic of the cretaceous series of Europe, 

 and he states that the marls very much resemble beds containing similar 

 shells in New Jersey, about 3G0 miles to the northwards. The marls 

 extend from South Washington to Rocky Point, fifteen miles from Wil- 

 mington, where they are covered by an eocene deposit, to which has 

 been apphed the name of Wilmington limestone and conglomerate. 

 This formation has been considered to be an upper secondary rock, but 

 Mr. Lyell says that he could find no organic remains in it which sup- 

 ported this opinion, and though the specimens he obtained at Wilming- 

 ton were only casts, yet many of them belong to the genera Oliva, 

 Cyprgea, Conus, Calyptrcea, and Sihquaria; and further, two of them 

 appeared to agree with casts of Pecten membranosus and Lucina pendata, 

 eocene fossils ; aud he afterwards found that a Pectunculus, a Vermetus, 

 and a Lunulite, which he obtained at Rocky Point, occur also in the 

 limestone of the Santee Canal, in South Carolina. The Wilmington 

 limestone and conglomerate extend to the town after which they are 

 named, and thence along the coast to the mouth of Cape Fear River, 

 and they are almost everywhere overlaid by a miocene deposit. 



