Geology of North Carolina. 233 



on exposure to the air, they speedily crumble to pieces. They 

 are met with at different depths, from three to eight feet, and 

 the marine deposits are chiefly in beds or ridges crossing the ca- 

 nal from east to west. Conch-shells, scollops and clams, are 

 the most common varieties of shells, and they correspond both 

 in kind and appearance with the marine aggregates accumula- 

 ted on the sandy beach near cape Look-out. The clam shells, 

 however, are frequently of a larger size than those met with 

 at present. 



4. A soft deep blue clay, which is sometimes in contact with 

 the potter's clay, (number 2.) though it is frequently separated 

 from it by the layer of sand, (number 3.) The inhabitants as- 

 sert, that this blue mud corresponds in its character precisely 

 with that which is now found in the bed of the adjacent ocean. 



Shell Marl. 



In ascending the Neuse towards Newbern, the banks gen- 

 erally appear low, but occasional bluffs present themselves, all 

 of which I should have examined more minutely, had not the na- 

 ture of my conveyance, (a public boat,; prevented. The most 

 conspicuous bank, however, I had an opportunity of inspecting 

 with some attention. It occurs at Johnson's Point, four and a 

 half miles below Newbern, on the south side of the river. This 

 contains an extensive deposit of marine shells, more or less de- 

 cayed, and blended with clay, constituting that valuable species 

 of manure, called shell marl. The bed occupies a space of 

 about five feet above low water mark, and consists of a vast col- 

 lection of marine substances, among which are scollops, oysters, 

 clams, conchs, corals and madrepores. Immediately above the bed 

 of shells, is a thin layer of clay, exhibiting prints of shells only, 

 the shells themselves having apparently mouldered entirely 

 away. Above the clay, the remainder of the bank, about fif- 

 teen feet, is occupied by sand. 



The Report describes several varieties of limestone and 

 stone marl in the low country. In an economical point of 

 view, these are interesting, especially as it is probable one of 

 the varieties will form the water proof cement. The oolitic 

 limestone and stone marl are thus described. 



Limestone of the Sarpony Hills. 



In the eastern part of the county of Wayne, is a high ridge 

 of land extending along the south sWe of the river for several 

 miles, and dividing the waters of this river from those which 

 pursue a longer course to the Cape Fear. These hills are covered 

 with large round blocks of fine stone marl, beneath which, at the 

 Vol. XIV.— No. 2. 4 



