OF SOUTH CAROLINA. 123 
or else in the slate itself. Wherever the slates are at all arenaceous or rough to the touch, they 
invariably become hard below the surface, and it is only where the slates are entirely talcose that 
they remain soft even to a short depth—facts highly interesting to those who would engage in 
mining speculations; for rocks that at the surface appear soft, and yield readily to the pick, thirty 
or forty feet lower become so hard as to require the force of gun-powder at every step; and besides 
this, the difficulty of grinding is increased in a greater degree. 
The quartz veins that are found on the ridges, in the vicinity of the mines, contain not a particle 
of gold. 
But I have, in the preceding pages, already described the gold region of Lancaster. Besides gold, 
other minerals occur in the District, that may, at some future period, have some economic value. 
I observed indication of the existence of iron ore in a thick bed near Blackman’s mine, which has 
never been examined below the surface. 
The pyritous slate thrown out of the mines yields, on disintegration, a considerable amount of 
sulphate of iron, or copperas. This salt is easily extracted by the simple process of lixiviation. 
At Hale’s mine it occurs in great abundance. In the talcose slates there are numerous localities. 
I examined the trap dykes of the gold formation, with some care, in order to determine whether 
or not they had exerted any influence on them; but, although many of the mines are intersected 
by dykes, I could find no alteration produced in the gold-bearing portions, notwithstanding that 
they have, in many cases, been worked on both sides of the dykes. 
The granite of Lancaster is best exposed in the south-western corner, along the Catawba, where 
the superincumbent slates have been removed by denudation. 
York District. 
Yorkville stands upon a granitic ridge, which presents favorable opportunities for the study of 
the granite of the District. This ridge, which extends towards King’s Mountain, is composed of a 
erystalline granite with white feldspar and black mica. Huge rounded masses are left standing 
above the surface, which are often, as elsewhere, mistaken for boulders. Similar appearances are 
presented by the granite in the south-eastern corner of the District. Between this point and the 
village an unbroken ridge exhibits granite overlaid by gneiss, and cut by trap dykes of considerable 
extent. A series of these dykes may be traced from the intersection of the Chesterville and Herron 
Ferry road and the York road, almost to the village. Near the 13-mile post one is found, which 
occupies a considerable space. Strange to say, it was cultivated, exhausted, and tumed out, as 
waste. No where is the alternation of trap and granite more conspicuous than along this section. 
The dark brown soils of the trap contrasting with the light gray of the granite. 
The south and south-eastern part of York is more broken, and presents many interesting geolo- 
gical sections. 
At Smith’s Ford hornblende slates occupy a considerable space on both sides of the river. On 
the left bank, or York side, it reposes against the granite exposed on the hill side. The gold mines 
of this locality are highly interesting, as showing the connection between the auriferous veins and 
the underlying granite. At one place a vein of quartz, containing gold, is seen passing from the 
granite through the superincumbent slates; at another a similar vein intersects hornblende rock. 
