146 GEOLOGICAL SURVEY 
Whenever the porcelain clays of the State come into use, the pure, white deposits of Congaree 
Creek will hold a prominent place. 
Second Creek exposes, on its banks, a fine section, where it passes over the outcrop of the sand- 
stone. The first three feet, in the descending order, is composed of silicified shells, passing into 
sandstone, five feet thick, the whole resting upon a bed of sand and gravel, nine feet. The sur- 
face of the sandstone contains embedded fragments of bones. ; 
Among the shells I recognised Cardita planicosta, Pectunctulus pulvinatus, and Cytherea, sp? 
but the whole seem thrown together in confusion, and not a single valve is found in juxtaposition 
with its fellow. 
These localities are highly interesting, as placing beyond doubt the relative position of the sili- 
cified shells and sandstone. 
Between Congaree Creek and Lexington Court House, on Red Branch Creek, vast beds of varie- 
gated clays are exposed, in the ravines, on the southern slope of the hills, which are protected from 
further denudation by horizontal beds of iron ore and ferruginous sandstone. The ore is good, but 
does not occur in sufficient quantity to be of any economic value.. Congaree Creek is the most 
eastern point to which I have traced the sandstone of the Hocene. 
The spring branches, and even streams of considerable size, sink into the sands of this region, 
and are lost, or re-appear at distant points, in the form of springs; and to this fact is due the almost 
entire absence of swamps, and the consequent healthfulness of the sand-hills of the State. 
Near one of the head streams of Congaree Creek the silicious clay bed may be seen, cropping 
out on a hill 80 or 100 feet high—it is four feet thick, and rests, as at Aiken, on beds of kaolin, sand, 
and gravel, and is covered by ferruginous sandstone. 
There is a quarry opened in the bed, at this place, which has furnished materials for chimneys 
for the surrounding country. For this purpose this indurated clay is admirably adapted, for it may 
be sawed into blocks, and fashioned with the axe into its proper shape, and it resists disintegration 
well. Add to this, that its extreme lightness renders the carriage and subsequent handling compa- 
ratively easy. 
The next remarkable locality of silicified shells, towards the northern boundary of the Buhr-stone 
formation, is found on Beaver Creek, not far from its junction with the Congaree, and at Mr. Oliver’s 
mill. The bed of silicious clay, which is ten feet thick, at this place, is quite dark, and when wet, 
almost black. It is laminated and quite hard, and breaks with a conchoidal fracture. It contains 
much iron pyrites, and a spring that issues from it is highly chalybeate. It is, as usual, associated 
with silicified shells of Eocene species. 
A short distance west of this is another instructive exposure, near a little mill, on Ball Creek. 
Here the bed of laminated hard clay, is twenty feet thick; and, like that at the last locality, it breaks 
with a conchoidal fracture. 
At Col. Rumph’s, a few miles east of Oliver’s, I examined a fine section, composed, towards the 
bottom, of beds of quartzose sand, porcelain clay, &c. This is overlaid by the bed of silicious clay, 
which is thirty feet thick; and above this, a bed of iron ore, already mentioned, containing very 
perfect casts of Cardita planicosta, which must have existed in vast numbers, for some of the 
masses of jron ore are completely filled with them. 
The bold hills of this locality show the great thickness of the Buhr-stone formation of the north- 
