Tertiary Formations of the United States. 305 



almost eqnally near to the Ostrea bellovacina and the 0. sellaformis, so 

 widely disseminated throngh the eocene formations of South Carolina 

 and Georgia, is found in the uppermost beds of the formation at 

 Coggin's Point, on the James River. The part of Virginia to which 

 these remarks refer, is a flat region, forty or fifty feet above the level 

 of the sea. The miocene strata which compose the upper beds con- 

 sist sometimes almost exclusively of shells, and in the neighbourhood 

 of Williamsburg Mr. Lyell collected eighty species, which bear a 

 great resemblance generically, and in their relative numerical force, 

 to collections from the Suffolk crag and the Faluns of Touraine. 

 Among these Testacea are several species of Astarte, some very analo- 

 gous to those of Suffolk, the Voluta mutabilis, which resembles the 

 V. Lamberti, also Conus diluvianus, Lucina squamosa, and L. divari- 

 cata. Mr. Lyell says there are many other analogies among the 

 Mollusca, besides the occurrence of several corals, Echinodermata, 

 fishes' teeth and bones of Cetacea ; but he shows that the most im- 

 portant point of comparison is in the proportion of recent to extinct 

 Testacea. Out of eighty-two species which he collected at Williams- 

 burg, sixteen are considered by Mr. Conrad to be recent, and found 

 for the greater part living on the coasts of the United States. The 

 existing species, therefore, are in the proportion of one-fifth of the 

 whole, which agrees well, says the author, with the average per-centage 

 in the shells obtained by him in 1 840 from the Faluns of Touraine. The 

 entire number of American miocene shells known to Mr. Conrad is 

 238, of which thirty-eight have been identified with recent species. 



North Carolina. — In the neighbourhood of South Washington, on 

 the north-east branch of Cape Fear river, Mr. Lyell found the dark, 

 bluish marls of the cretaceous series, to which his attention had been 

 directed by Mr. Hodge's paper in Silliman's Journal*. They closely 

 resemble, in composition and organic contents, those in New Jersey, 

 and abound with Belemnites mucronatus, Exogyra costata, and a spe- 

 cies of Gryphsea resembling G. columba ; Mr. Lyell also found in 

 them Ostrea vesiculous and O. pusilla of Nillson, likewise Anomia 

 tellinoides, a species of Plagiostoma, and several new shells. These 

 marls extend to the south of Lewis Creek, for several miles along the 

 banks of the north-east branch of Cape Fear river, nearly to Rocky 

 Point, where they are covered by the Wilmington limestone and 

 conglomerate. This formation, which is overlaid by miocene strata, 

 and ranges to Wilmington, as well as along the coast to Cape 

 Fear river, has been considered by Mr. Hodge, and other geolo- 

 gists, to be an upper secondary deposit, or interposed between the 

 eocene and cretaceous series; but Mr. Lyell could find in it no or- 

 ganic forms which supported this opinion, nor could he learn that any 

 had been discovered. On the contrary, the only determinable species 

 apparently agree with the Lucina pendata, an Alabama shell, and 

 Peclen membranosus, both eocene fossils. The organic remains at 

 Wilmington are only casts, but are referable to the genera Cardium, 

 Nucula, Corbula, Cardita, Venus, Area, Natica, Oliva, Cypraea, 

 Conus, Calyptraea, and Siliquaria. Associated with these remains 

 * Vol. xli. p. 332, 1841. 



Phil. Mag. S. 3. Vol. 23. No. 152. Oct. 1843. X 



