Oct. 1847.] 



281 



Mississippi Eocene, and observed that not* more than 10 species would be found, 

 on comparison, identical with Claiborne shells. I had reference to the sand at 

 Claiborne, and not including the limestone above it. A careful comparison has 

 reduced the number to two species, for the Dentalium, which when at Vicks- 

 burg (without a Claiborne specimen for comparison) I had supposed to be D. 

 tkalloides, is a distinct, though closely allied species. 



This newer portion of the Eocene in Mississippi is represented in Alabama 

 by the white limestone at St. Stephens on the Tombeckbe river, and the simi- 

 lar rock which constitutes the uppermost stratum at Claiborne, on the Alabama 

 river ; all being admirably connected by the abundance of Nummulites Mantelli. 

 There is a similar limestone in Charleston County, South Carolina, in which I 

 found Scutella Lyelli and Peclen calvatus, fossils, of the Claiborne limestone, 

 and both rocks are probably of the same geological age. The limestone of 

 Tampa Bay, Florida, is included in the Upper Eocene series, but as yet no 

 fossil has been obtained from it identical with a species of the Carolinas, Mis- 

 sissippi or Alabama, unless it is a specimen of C'archarias megalodon, which 

 Capt. Powell, of the Navy, found on the bay shore. 



The only species of Crassaiella which occurs at Vicksburg, is more nearly re- 

 lated to C. lumida of the Paris basin than to C. alia of Claiborne. 



Ostrea sellceformis characterises the lower division of the Eocene formation. 

 It occurs abundantly beneath the fossiliferous sands of Claiborne ; at Vance's 

 Ferry, South Carolina: and on the right bank of James river, below City 

 Point, "Virginia. I also refer to this section, the localities at Fort Washington, 

 Piscataway, and Upper Marlborough, Maryland. Other characteristic fossils 

 are Cardila planicosta and Turritella Mortoni, the former occurring at Piscata- 

 way ; at Claiborne, Alabama ; and also at Marlbourne, on Pamunkey river, 

 Virginia, the residence of Edmund Ruffin, Esq. 



The following table illustrates the two editions of the Eocene : 



CHARACTERISTIC FOSSILS. 



DIVISIONS. 



LOCALITIES. 



Upper 



or 



Newer Eocene. 



Vicksburg, Miss., white limestone 

 of St. Stephens, and of Claiborne, 

 Alabama, and part of that in Charles- 

 ton Co., South Carolina. 



Scutella Lyelli. 



S Rogersi. 



Pecten Poulsoni. 

 Nummulites Mantelli. 



limestone in the vicinity of Tampa 

 Bay, Florida. 



Nummulites Floridana. 

 Cristellaria rotella. 

 Ostrea Georgiana. 



Lower 



or 



Older Eocene. 



Fossilliferous sands of Claiborne, 

 and St. Stephens, Al. of the Washita 

 river, near Monroe, La.; Pamunkey 

 river at Marlbourne, and Eocene 

 green sand, on James river, below 

 City Point, Va.; Fort Washington, 

 Piscataway, and Upper Marlborough, 

 Md. 



Cardita planicosta. 

 Blandinga. 



Crassatella alta. 

 Ostrea sellaeformis. 

 Turritella Mortoni, &c. 



*In the paragraph alluded to, this word was accidentally omitted. I did not, 

 when it was written suppose that 10 fossils would be found to correspond with 

 the species of the Claiborne sands. 



