Discovery of a Chambered Univalve Fossil. 187 



Art. XVI. — Discovery of a Cliamhered Univalve Fossil in the Eocene 

 Tertiary of James River, Virginia ; by M. Tuomey. 



Thinking that it may have sufficient interest for the pages of this 

 Journal, the following notice of the discovery of a Nautilus in the Eo- 

 cene on James River, Va., is communicated. 



Mr. Lyell during his visit to this portion of the tertiary of the United 

 States, directed my attention to the broken link in our great cretaceous 

 formation, presented by Virginia. At his suggestion, I determined to 

 observe any fossils that may come under my notice, with a view to the 

 elucidation of this interesting point. The liberality of Capt. H. H. 

 Cocke, U. S. N., afforded me a good opportunity of examining the fos- 

 sils of the well known eocene locality at Evergreen, near City Point, 

 James Rivei*. Capt. C. at the instance of Edward Ruffin, Esq. editor 

 of the Farmer's Register, who is engaged in the investigation of the ter- 

 tiary of Lower Virginia, caused a shaft to be sunk at the base of the 

 escarpment at the locality just mentioned. In this shaft and at a depth 

 of about twenty feet below the level of tide water the fossil referred to 

 was found. It was imbedded in the dark colored tenacious clay con- 

 taining much green sand, common to some of the eocene strata of this 

 region. The exterior of the shell is much decayed, but the pearly 

 surface of the interior is well preserved, and by removing portions 

 parallel to the aperture the concave septse and siphunculus can be 

 seen. It was associated with eocene species of Turritella, Crassa- 

 tella, Pectunculus, a small Panopsea, and a little lower in the same 

 stratum was found a gigantic Ostrea, measuring in height eight and a 

 half inches, breadth five and a half inches, and weighing five pounds. 

 The upper valve of this Ostrea agrees with the description of O. per- 

 crassa, Conrad, but in the lower valve the cartilage fosset is deep. The 

 muscular impression in each valve exhibits a cavity extending upwards 

 into the substance of the shell about two inches. A person seeing but 

 this huge individual, and the common form of O. compressirostra. Say, 

 found in the same stratum, would pronounce them distinct species ; but 

 I am in possession of a suite of specimens showing the intermediate 

 forms between the two, and am convinced that this enormous fossil is 

 but a full gi'own O. compressirostra. 

 Petersburg, Va., June 10, 1842. 



