1898.] NATURAL SCIENCES OF PHILADELPHIA. 417 



The three species previously noted as having been collected from 

 the bottom of the old south level near South Mills, N. C, were Uro- 

 salpinx cinerea, Fulgur carica and Ostrea virginica — the elevation 

 of the surface at this point being about 11 feet. 



All the forms, however, listed below, excepting Urosalpinx cin- 

 erea Say, were obtained from a locality along the Deep Creek level 

 of the Old Canal, at a point four miles north of Wallaceton, Va., 

 and from a depth of about ten feet, the elevation of the surface being 

 about sixteen feet. The Deep Creek level is next north of the sum- 

 mit level of the old canal, the latter having an elevation of about 

 twenty feet. 



Ostrea virginica, generally much larger and more numerous than 

 at South Mills or at north of Wallaceton, was likewise brought up 

 in the dredgings from the bottom of the feeder leading from Drum- 

 mond Lake, say at approximately ten feet below the surface level, 

 which, at the point under consideration, is about twenty feet above 

 tide, the elevation of the surface of the lake being, according to a 

 survey made by the U. S. Engineers during the winter of 1895-1896, 

 22 T VV feet. 



Mollusks from the base of a low escarpment on the western bor- 

 der of the swamp near Suffolk, Va., and near the Jericho Canal, 

 which leads north-westwardly from Lake Drummoud to the Nanse- 

 mond River, have been noted by Prof. N. S. Shaler. After listing 

 the species as identified by Dr. W. H. Dall, he says: "Traces of 

 this same deposit occur a few miles south of Suffolk, and I suspect 

 the existence of similar beds near Elizabeth City. From certain 

 comminuted fragments taken from the bottom of the main Dismal 

 Swamp Canal, it seems to me not improbable that the beds were 

 touched in making that excavation. I am, therefore, disposed to 

 believe that the foundation rocks beneath the swamp district consist 

 mainly of the beds indicated by the foregoing list of fossils." 2 



Prof. Shaler thus indicates fossil beds which the recent deepening 

 of the Dismal Swamp Canal has abuudantly verified, though very few 

 of the species in Prof. Shaler's collection and our own are the same ; 

 and yet, as will be seen further on, upon analyzing the forms in the 

 two collections, they tell a similar geological tale. 



We now insert tables of the mollusks from the Dismal Swamp 

 and the Jericho Canal localities. 



2 Tenth Annual Eeport U. S. Geol. Survey, page 316. 



