CORUNDUM IN IGNEOUS HOCKS. 
31 
c. Yellowish vermieulites, varyiiij; coiisidei-ubly in thickness, the maximiiin 
being 6 to 8 inches ; in places absent, so that h comes directly in contact with d: 
where present, o often merges into d. 
d. Green chlorite, varying in thickness much like c, and in places absent. 
e. Chlorite and corundum, sometimes with a little vermiculite. In i)laces tliis 
mass may be largely corundum, and it is what is called the " corundum vein," 
varying in thickness from a few inches to 12 or 15 feet. 
f. Green chlorite; so far as observed always present, and varying in width 
from 1 to 12 inches. 
(J. Enstatite; in places hard and comi)act, and in widths of several feet: 
usually merges into h. 
h. Talcose rock, usually fibrous, varying in thickness from a few inches to 
several feet. 
/. Dunite, more or less altered, friable, and stained with ferric oxide. 
k. Dunite, apparently unaltered, quite extensive. 
•iWiiiillii 
'^m 
mm, 
i 
lie 
1 
I 
nl //^VA ]/ /y 
I If I'l; I 
Fig. 6. — Ideal cross section of a corundum border vein at the Corundum Hill mine, Nortli 
Carolina, a, Fresh and unaltered gneiss ; b, decayed and unaltered gneiss ; c, vermicu- 
lites ; d, green chlorite ; e, corundum-bearing zone ; f, green chlorite ; <j, enstatite ; 
h, talcose rock ; ij clay ; /, altered dunite ; k, unaltered dunite. 
Between A and j a seam of yellowish clay (i) is sometimes observed 
which often contains a narrow seam or fragments of chalcedony. 
From Avhat conld be learned by actual observation and inquiry 
among the miners, c and d are sometimes absent, and when this is the 
case, e, a mixture of chlorite, A^ermiculite, and corundum, is seem- 
ingly in direct contact with h. The chlorite, however, on the dunite 
side of the section is constant. The thickness of the several zones 
(«, &, r, etc.) in such sections varies greatly at different places, and 
the distance across the sections may be said to vary at different 
points, even in the same region, from a few feet to 30 or 40 feet. The 
accompanying diagram (fig. 6) represents the cross section of a 
border vein observed at the Corundum Hill mine, Cullasagee, Macon 
County, N. C. 
