OF THE SOUTHERN ATLANTIC STATES. 99 



are, as seen by the accompanying catalogue, about eighty species 

 found at this locality. Of these, twelve are recent, and twenty at 

 least heretofore unclescribed. Some yet undetermined remain in 

 the hands of Mr. Conrad, and of these only the genera are given. 

 The Oliva idonea has been previously described by Mr. Conrad ; 

 it is one of the most beautiful shells found here, being finely 

 preserved, and most of the specimens not having lost their nat- 

 ural polish. The people living in the neighborhood know them 

 by the name of " key shells," from their procuring them to attach 

 to a bunch of keys. The cones are of the species adversarius, 

 so named from their being nearly all reversed ; one of mine is 

 the only exception known. The bivalves are only occasionally 

 met with entire. 



It is remarked that the water in the well never varies in fresh- 

 ets nor droughts, and tales are told of ineffectual attempts hav- 

 ing been made to sound it, and of a strong current setting 

 through it, sucking down whatever is thrown in. That there is a 

 current I doubt not, it being nothing unusual for a stream of 

 water to sink suddenly under ledges of limestone, as at the 

 Eutaw springs in South Carolina ; and the limestone of the sec- 

 ondary formation I believe to be not far below the surface of the 

 water, perhaps dh*ectly under the blue sandstone at the surface, 

 which is very likely the upper rock of that formation, and the 

 blue clay the lowest of the middle tertiary, as it often is, (the 

 lowest tertiary is wanting in this part of the country.) The 

 hmestone of Jones county is not far oft, and such sinks as these 

 are frequent over limestone beds ; in Georgia they are called 

 " limestone sinks." 



With my vallise and saddle-bags well stored with specimens, 

 and a keg full strapped behind the saddle, I proceeded to South 

 Washington, on the way to Wilmington. In this neighborhood 

 I discovered again the secondary formation on the northeast banks 

 of Cape Fear river. The rock is a blue sandstone, contain- 

 ing the characteristic Exogyra costata, Belemnites, Plag-iostoma 

 pelagicum, Anomia ephippiwn, &cc. The existence of this rock 

 between the tertiary deposits on the east and the west, seems to 

 indicate an inticlinal axis here, which extending north, accounts 



