260 Cincinnati Society of JSTatural History. 



fossils are frequentl}' water- worn, always with disunited valves, and 

 appear to have been transported. Occasionall}' a specimen occurs not 

 in the least abraded, a circumstance which indicates the vicinit}? of 

 the Petersburg deposits to the mouth of the river. The strata occur in 

 a meadow, and consist of blue marl, of a sand}' texture, often inter- 

 mixed with small gravel and ferruginous sand, full of shells ; there is 

 here also a proportion of gravel, of rounded quartz, occasional!}^ of 

 large size. Water-worn fragments of bivalves are abundantly inter- 

 mingled with entire shells, and many species occur with connected 

 valves. This is particularly the case with the burrowing shells, as 

 Panopana^ but also, though less frequently, with the large Venus tri- 

 dacnoides, Crassatella undulata^ Astarte concentrica^ Cytherea al- 

 baria, two species of Chama, and even two species of Ostrea are not 

 uncommon; but thei-e is nothing like an oyster bed in these strata 

 which might indicate shoal water. The proportion of oysters to the 

 other bivalves is about the same which the dredge furnished at the 

 mouth of Cape Fear river, North Carolina, at the depth of eight 

 fathoms. 



In 1844, Prof. J. W. Bailey* identified numerous living Infusorial 

 forms with the fossil Infusoria, from the Miocene at Petersburg, Va., 

 and Piscataway, Md., and described several new species. 



Mr. Conradf described, from the Miocene, at Petersburg, Va., Crepi- 

 dula cymhceformis ; from the Eocene at Marlbourne, Hanover county, 

 Va., Cytherea eversa, C. liciata, C. subimpressa; from Stafford county, 

 Va., C. pyga ; from Claiborne, Ala., Cardita densata ; and from near 

 Santee, South Cai-olina, Pecten elixatus. 



Dr. Edmund Eavenel described, from the Miocene of South Carolina, 

 Pecten mor ton i ; from the Eocene, Terebratula canipes, and Scutella 

 pilenssinensis, now Mortonia pileussinensis. And Dr. Robert W. 

 Gibbes described, from a bed of green sand near the Santee canal, and 

 about three miles from the head waters of Cooper river. South Carolina, 

 Dorudon serratus.\ 



In 1845, Prof. James Hall§ described, from Tertiary, slaty, bitumin- 

 ous limestone, on the dividing ridge between the waters of Muddy 

 river flowing eastward, and those of Muddy creek flowing into Bear 

 river on the west, in long. Ill deg., lat. 40 deg., 3fya tellinoides, 



'■■' Am. Jour. Sci. and Arts, vol. xlvi. 

 t Proc. Acad. Nat. Sci., vol. ii. 



X This species was erromously mentioned as Cretaceous on page 15, vol. iii,. of tliis 

 Journal, or page 51 of this article. 

 §» Fremont's Expl. Exped. 



