132 THE PIEDMONT REGION. 



are alike and seem to shade off insensibly into each other. This explains 

 why, in nearly every township, the occurrence of rock, well adapted for 

 building, and called granite, is reported in greater or less quantities. 

 The most marked difference is, that where the stratiform character of the 

 gneiss is most marked the hornblende beds, associated with the granite, 

 and of such high value as a soil yielder, disappear. Although traversed 

 by numerous veins, this rock has so far furnished nothing of importance 

 to the miner in this State. Its general dip is slight and to the southeast. 

 On its southern border, however, the gneiss rock is found with a vertical 

 dip, as at Edgefield C. H. South of the Saluda river, in Lexington, it is 

 found between the granite and the clay slates, dipping X. E. 80°. In 

 Xewberry, near the thirt}- mile post on the Columbia road, a coarse feld- 

 spathic gneiss, alternating with hornblende slate, forms an anticlinal ridge, 

 dipping southeast on its southern, and northwest on its northern slope. 



Immediately overlying the gneiss, belts of hornblende slate, of no great 

 breadth, and having nowhere an ascertained thickness exceeding twenty- 

 five feet, are exposed. 



MICA SLATE. 



These belts of hornblende generally surround isolated areas of mica 

 slate, which overlie them. The}^ are found chiefly towards the north, 

 along the base of the triangle formed by the affluents of the Santee, or to 

 the west of this river system in Abbeville, Anderson, Greenville and Pick- 

 ens. They occupy the summit of ridges, as of King s Mountain, in York. 

 On the water courses they give place, first to the hornblende slate, and 

 then to the gneiss, which forms almost everywhere the beds of the streams. 

 They have an ascertained thickness, exceeding in no single locality one 

 hundred feet. ]\Iines sunk in them have, in several instances penetrated 

 to the underlying gneiss. Mica slate thus occurs as large islands, the 

 remnants, perhaps, of what may once have been a succession of wave-like 

 parallel folds, dipping gently with the Atlantic slope to the southeast and 

 covering the entire surface, but disappearing long ago under the erosive 

 action of the present river system of the State. Numerous gold mines 

 and veins bearing copper, lead and silver, have been found in these rocks, 

 and, to a limited extent, worked. The iron furnaces of Cowpens and 

 Hurricane Shoals are also located in this formation. Mica of excellent 

 quality has been mined in Dark Corner township, Anderson, and in Ab- 

 beville. In the former locality beryl and copper are also found ; corun- 

 dum and zircons are found in Hall township, Abbeville, and in other 

 localities. Asbestos occurs near Glenn Springs, Spartanburg, a noted 

 health resort, the curative virtues of whose waters, with those of many 



