OF SOUTH CAROLINA. Heel 
Or THE PLIOCENE or SourH CAROLINA. 
Overlying the Eocene of Maryland and Virginia there are numerous isolated beds, consisting of 
sand, clay, and marl, which are every where richly fossilliferous. According to Mr. Conrad’s latest 
determination* of the percentage of recent and extinct species of fossil shells in these, he finds, in 
344 species, 49 that are now living, making the proportion a little over 14 per cent. Those who 
follow Mr. Lyell’s classification, therefore, refer these beds to the Miocene period of the Tertiary. 
[t will appear, from the investigations recorded in the following pages, that, in South Carolina, the 
percentage of recent species is far greater than this, and hence I have referred our beds to a newer 
division of the Tertiary—the Pliocene. 
A glance at the map will show how irregularly these beds are scattered over the State. The 
finest exposures are found in the Eastern Districts, resting on the Cretaceous marls. In Darling- 
ton and Sumter the fossils are in a better state of preservation, and hence the deposits in these 
Districts have a more recent appearance, although, as it will appear, the organic remains are iden- 
tical. 
Mineralogically, the Pliocene beds of the State differ widely from the Miocene of Maryland and 
Virginia: in the latter State the amount of carbonate of lime in these beds, according to Mr. Ruf- 
fin’s researches, does not average 40 per cent. whilst, in the South Carolina beds, the average is 70 
per cent. It is, in this respect, even more uniform than the Hocene. 
In Virginia it is not difficult to distinguish the Eocene and Miocene marls, by their mineral char- 
acters alone, but in South Carolina nothing but the evidence of organic remains will enable the 
Geologist to arrive at a reliable conclusion. The sections on the Waccamaw and Peedee show very 
clearly the depressions in the cretaceous rocks, in which the Pliocene beds are situated, and ina 
similar manner they are found resting on the Eocene on the Cooper, and elsewhere. In general, 
they are deposited on a plane that rises gently from the Atlantic, till it reaches its greatest eleva- 
tion, in Darlington District. Although these deposits are confined to mere patches, that have been 
protected from denudation by the more elevated portions of the formations on which they repose, 
yet they may be traced, at short intervals, from Horry to Darlington, and from thence, by Lynch’s 
Creek, to Sumter. Between the localities in the latter District and St. John’s Berkley, where the 
next exposure occurs, there is a considerable gap. It next appears on Cooper River, at Mr. Car- 
son’s, and at the Grove, and still lower, on Goose Creek, which is the most southern point in the 
United States at which Miocene or Pliocene beds have been observed, unless it be a locality on 
the Edisto, which I have not seen, and only determined by some fossils in the possession of Dr. 
Joseph Johnson, of Charleston. 
The best point to commence the examination of our Pliocene deposits is on Little River, a small 
stream, one prong of which rises in North Carolina. It empties into the Atlantic in the south-east- 
ern corner of Horry District. 
At the Timber Landing, below Capt. Randal’s dwelling, and on the same side of the river, a bed 
is exposed, the upper surface of which is about the level of high-water. It is laid bare at low- 
water, in the sloping beach extending into the bed of the stream. A little higher it seems to thin 
*Am. Jour. Sci. and Arts, 2d series, May, 1846. 
