OF SOUTH CAROLINA. 103 
and the amount of denudation, as measured by them, is between 300 and 400 feet. We must not 
suppose that this denudation has always proceeded at the same rate, for we know, when the surface 
is covered with a dense forest growth, that the washing and waste of surface can amount to little, if 
any thing; but there was.a time when no such protection existed, and when this whole country 
was laid. bare, and so continued long after its emergence from the depths of the primeval ocean.— 
That the destructive agents were different and perhaps more violent than those at present in opera- 
tion, we have reason to believe. The beds of rounded pebbles of considerable size, that seem, in 
their downward passage, to have been entangled among the mountains, and that may be traced 
still farther south, show that a violent current has passed over the country—perhaps produced by 
the oscillations to which the surface was subjected during periods of disturbance. 
The cultivation of the Jand and consequent clearing of the surface of its natural covering of 
vegetable growth, is again accelerating denudation. 
If any one wishes to know what has become of the enormous mass of matter removed by this 
force, let him examine the vast beds of clay, gravel, sand, &c. that make up so large a portion of 
the Tertiary series, and Jet him commence this examination at the ferry below Augusta, and around 
Hamburg; and let him calculate the quantity of mud and finely comminuted matter carried down 
by the rivers of the State, even in a single season. He will then fully comprehend the double 
change produced by denudation—a waste in one place, and an accumulation to the same extent in 
another. 
PaLwozo1c AND OLDER SeconparRy Rocks. 
In Chesterfield, not far from the village, on Thompson’s Creek, I observed strata of highly in- 
clined rocks, much more silicious than the clay slates of that locality, and altogether of a coarser 
aspect. I examined them for some distance above the mill, where they are well exposed, yet I was 
unable to find any fossils; nevertheless, they may belong to the rocks which occur in North Caro- 
lina, not far over the line, and which Prof. Mitchel refers to the Transition series. I saw the same 
rocks near 'axahaw, where they barely come to the surface on the slope of a hill. With these 
exceptions I have met with no rocks that can be referred to the Paleozoic period. 
New Rep SanpsTone. 
A strip of this rock, which extends, with little interruption, from Massachusetts, through Con- 
necticut, New Jersey, Maryland, Virginia, and North Carolina, terminates on Clay Creek, Chester- 
field District, about four or five miles from the line. 
In Massachusetts thin seams of bituminous coal are found in this rock; and in North Carolina 
coal was known to exist in it, and was worked in smiths’ forges before the Revolution. Trap 
dykes are common throughout the entire region occupied by this rock, and the coal in their vicinity 
is, in many instances, converted into anthracite. Ata place called the Gulph, on Deep River, in 
North Carolina, a bed over six feet in thickness is exposed, which has been worked near the outcrop 
to supply the blacksmiths. Although bituminous, it has the aspect of anthracite, and scarcely soils 
the fingers, and burns with a white flame. It is overlaid by shale, containing nodules of clay iron- 
stone, enclosing organic remains. I found a specimen of calamites which; if not identical with, is 
