OF SOUTH CAROLINA. 137 
At Greenwood, a short distance higher up the river, the sand becomes a solid sandstone, which 
is found alternating with clay. 
I made diligent search for fossils, at this place, yet, notwithstanding the apparently favorable cir- 
cumstances presented by thick beds, evidently deposited in tranquil water, a single species alone 
rewarded me for my trouble, and that was Haumulus onyx, a fossil which had previously been 
found on Lynch’s Creek, by Dr. Blanding. 
Ou the river the shale now gives place to the underlying beds of sand, which become blended 
with the Tertiary beds of sand, clay, and gravel, that cover the surface and overlap the metamor- 
phie rocks above, and cover the whole of Marlborough. 
There are few sections more instructive than those presented by the Cretaceous beds of the Pee- 
dee. It is true that fossil species are not numerous, and, with a few exceptions, the shells occur 
only inthe form of casts, but every fragment is characteristic. The gentle dip of the strata, sel- 
dom exceeding an angle of 10°, marks the quiet manner of their elevation. In proceeding upwards, 
the superincumbent strata disappear at the surface, giving place to those below, as they succes- 
sively emerge from the water. 
The upper surface is very uneven, and at intervals between the bluffs the formation is removed, 
by denudation, altogether; the beds, however, preserve their relative position, and the depressions 
on the surface are often filled with Tertiary beds—to be described in another place. The unifor- 
mity of mineral character of the formation is very remarkable. The sections on the river extend 
over a space of sixty to eighty miles, and yet three or four well marked strata characterise the 
whole. First, beds of dark gray, and generally soft marl, varying somewhat in the amount of lime 
and silicious matter; next a stratum of hard lime or marl stone, much richer than the preceding, 
in caleareous matter, and very uniform in external appearance; and lastly the shale, which con- 
tains no lime, and which can be mistaken for no other rock in the State. It often contains iron 
pyrites, which gives rise to the sulphates found efflorescing on the surface. 
Mr. Ruffin, who examined all these localities with care, pointed out the interesting fact, that 
every one of them occurs upon the right bank of the river. He noticed that this was also the case 
on the Savannah, and rightly concluded that an effect so general could only be the result of some 
common cause. I think that this phenomena is not confined to these rivers, nor to South Carolina, 
but may be seen in those to the Kast and West; but I shall take up this subject in another place. 
It is quite evident that the Cretaceous formation underlies the whole country between the Little 
Peedee and Lynch’s Creek, for I found a fine bed exposed at Hodge’s mill, about eight miles above 
Gallivant’s Ferry, on the former river. This is by far the richest bed in fossils that I have seen ; 
but they were in a chalky state, and the marl being quite soft, it was impossible to preserve them. 
On Willow Creek the formation is exposed for miles; and on Jeffrey’s Creek the shale comes to 
the surface in numerous places. 
Between Mar’s Bluff and Darlington Court House, I observed it, on Black Creek, where it is cov- 
ered by sand, and at other points along the road. Near the village it underlies the Tertiary beds, 
and is exposed in thick fissile beds, at Col. Ervin’s marl pit. 
Direetly south of the Court House the Secondary rocks are exposed, on Sparrow Swamp, near its 
junction with Lynch’s Creek. ‘This locality is found near the point where the corners of Marion, Wil- 
liamsburg, Sumter, and Darlington Districts meet. It is the oldest, and was almost the only locality 
35 
