126 GEOLOGY OF NORTH CAROLINA. 
coarse pottery, and sand for mortar. There is also on the edge 
of Tossnot swamp, in Nash, a bed of bog iron ore in this forma- 
tion. It is generally about five feet beneath the surface, IS inches 
thick, and with lumps, or nodular masses, of the same, above. 
Iron of an indifferent quality was manufactured from it at a forge 
on the Big Swamp, in 1814-15, and a part of 1816, when the 
forge was burnt. The quantity of the ore is not such as to war- 
rant the expectation that the enterprize will be renewed. 
Below the limits of the fixed rocks, the same associations and al- 
ternations of clay and sand are continued, with the addition, either 
there, or at no great distance below, of marine organic remians. 
The upper limit of these, is at Murfreesboro' on the Meherrin, 
Scotland Neck on Roanoke, near Enfield on Fishing Creek, a little 
below the Falls on Tar River, at Bass's Ferry (a small quantity) 
on the Neuse and 12 miles above Elizabeth on the Cape Fear. 
None have been observed within the limits of the state, on Lum- 
ber River. They occur at intervals from the points just na- 
med to the ocean. 
Maclure, in a sketch or outline of tne geology of the United 
States, prepared thirty years ago, represents as one alluvial for- 
mation, a tract commencing at the eastern extremity of Long Is- 
land, and extending through the Middle and Southern Atlantic 
States, embracing the whole of the south-eastern half of North 
Carolina that is now the subject of remark. But it has been as- 
certained that different and distant parts of this district, are unlike 
each other, in age and character. So much of it as lies within the 
limits of the state of New Jersey, isproved by the imbedded fos- 
sils, to be contemporaneous with the cretaceous system of Europe. 
There are only a few small patches of tertiary in that state. In 
Maryland the tertiary formations come in in great force, occu- 
pying both sides of the Chesapeake bay, and passing through Vir- 
ginia, are represented as attaining their greatest width in North 
Carolinia, and to be succeeded by secondary formations in the low- 
country of South Carolina. But the tertiary of North Carolina, 
is different from that of the states lying north-east of it, exhibiting a 
much larger proportion of recent shells — species of which the ani- 
mal is still living on the coast. The proportion of living species 
in the deposits of Maryland and Virginia, is about 20, whilst in 
those of North Carolina, it rises as high as 50 or 60 per cent.* 
* For these facts, and of course for the conclusions drawn from them, the 
geologist is compelled to acknowledge himself indebted to the Conchologists, 
and to Mr. T. A. Conrad of Philadelphia, more largely than to any other indi- 
vidual. Two boxes of shells have been forwarded by the writer for exami- 
nation by him, from the valley of the Cape Fear; one from Walker's Bluff, in 
Bladen, and the other from the natural well in Duplin, from which, in part, the in- 
ferences just stated were drawn. If it be enquired why greater activity has 
not been displayed in collecting and forwarding the materials for determining 
the geological era of a large portion of the state, it may be replied, that the 
University is at a distance of between 70 and 80 miles in a straight line, from 
the nearest fossil shell. 
