THE PIEDMONT REGION. 133 



other similar springs in this region, is clue to the minerals dissolved from 

 these mica slates during their j^assage through them. 



TALC SLATES. 



Next in the order of superposition above the.-mica slates occur extensive 

 areas of talc slate. These rocks seem to have yielded more completelj^ to 

 the erosive action of the rivers even than the mica slates. They scarcely 

 appear at all in the angle enclosed between the Catawba and the Saluda. 

 Their largest outcrops are east of the Catawba, in Lancaster and Chester- 

 field, and separated from these by the whole width of the river system of 

 the State, eighty miles, to the southwest they occur on the further side of 

 the Saluda, in Edgefield and Abbeville. These two localities are the great 

 gold-bearing regions of the State. 



ITACOLUMITE. 



On Broad river, near the northern boundary of the State, where Union, 

 York and Spartanburg corner, an interesting series of rocks occur, the 

 most peculiar of which is a flexible* sandstone, the itacolumite or diamond 

 bearing rock, which gives its name to the group under the designation of 

 the itacolumitic series. Thus far only one diamond has been found in 

 South Carolina, though several have been obtained from the continuation 

 of these rocks, both in Georgia and in North Carolina. 



CLAY SLATE. 



South of the rocks above mentioned, and extending along the edge of 

 the tertiary from Edgefield to Chesterfild, a broad belt of clay slates 

 occur. On their southern border, among the sands of Lexington and 

 Chesterfield, or just north of the granite in Kershaw, Richland and 

 Edgefield, these clay slates dip northwest 14° to 18°. This angle increases 

 further north, until the slates stand vertically ; still further on the dip is 

 reversed to the southeast. In Edgefield and Lexington, where they occupy 

 the widest areas, these rocks seem to have had their positions much dis- 

 turbed, and Avhile the edges of the strata preserve their northeasterly 

 strike, their faces are turned alternately northwest and southeast — now 

 towards the mountains, and again towards the sea. These clay slates are 

 contiguous to the Jurassic strata of North Carolina. Mr. Tuomey found 

 in Chesterfield fossils which he credited to the new red sandstone, and in- 

 timated that these slates themselves might possibly be identified with the 

 paleozoic series. It seems at least certain that they overlie, and are, there- 



