OF SOUTH CAROLINA. 63 
Higher up the river the granite assumes a gneissoid character, and stretching across the bed of 
the stream, forms a series of picturesque cascades over a distance of a quarter of a mile. The 
thickness of the strata exposed here, and consequently the fall of the stream, is about 40 feet.— 
Towards the sources of the river the rock is covered and hid from view by Tertiary sandstone. 
On Twelve Mile Creek, near Lexington, crystalline granite is found forming the fall at the mill; 
it underlies the village, and appears at the surface to the East, and along the creek, to where the 
latter is crossed by the road to Youngner’s Ferry. 
At Granby, on the Congaree, disintegrated granite covers the surface, and from this place to the 
junction of the Saluda and Broad River, excellent localities are every where seen, of a fine-grained, 
compact, grey granite. At the Factory broad veins of red granite, resembling the Egyptian variety, 
penetrate the rock, and a fine sienitic granite is found at this place. On the canal the rock is inter- 
sected, in various directions, by flesh-colored feldspar. 
Near Fisher’s Mills granite is found outcropping from under the beds of clay and gravel upon 
which Columbia stands. Round masses of this Rock occur on the surface, and embedded in loose 
earth, near the bridge over the Saluda, and in various places north of the city. 
The rounded form and apparently detached position which they occupy in the banks of loose 
earth in which they are embedded, have caused them to be referred to true transported boulders. 
They are, however, masses of granite rounded in place, by disintegration. 
The rock originally presented a jointed i seams dividing it, by their intersection, into 
cubic blocks of various sizes. Disintegration commences at the angles, which, being the points of 
least resistance, are removed by exfoliation, or converted into a slightly cohering mass, which 
finally becomes a loose earth, enclosing the rounded pieces of rock. This earth is frequently 
removed from the crevices, and the globular masses remain standing alone, or piled upon each 
other, as they are often seen. It is in this manner that all the rounded masses of granite in the 
State have been formed; which can always be distinguished from transported rocks by their 
identity with the rocks with which they are 
associated. The sketch, Fig. 11, shows the 
mode in which these pseudo boulders are 
formed. 
Besides the granite range thus briefly in- 
dicated, there are other localities in this re- 
gion, which have little more than a local in- 
terest, and need not be minutely described. 
About four miles north of Cambridge, on 
i both banks of the Saluda, extending as high 
up as Neily’s bridge, huge weathered hemispheric masses of granite are seen, which frequently rise 
above the surface, to the height of ordinary houses. Their angles are completely rounded, and the 
masses are frequently fractured throughout their entire height. These fractures are the result of 
the disintegration which takes place at the surface of the ground: an undermining of the rock com- 
mences, and is continued until the projecting portions, by their weight, overcome the cohesive force 
of the rock, when of course they break off. The piling up of rocks upon each other, so often 
noticed, on account of their resemblance to works of art, is also the result of this cause. 
