38 
CORUNDUM, ITS OCCUREENCE AND DISTRIBUTION. 
7 miles west of Statesville, the amphibolite was exposed during explo- 
ration for corundum, which, according to Lewis,^ was found to 
occur in fine brown vermiculite, developed in zones along the borders 
of and penetra'ting the amphibolite, and varying in thickness from a 
few inches to 3 or tt feet. Fig. 11 is an ideal illustration of the occur- 
rence of corundum in the amphibolite at Hunters. In this figure, a 
represents a feldspar zone that is sometimes encountered in the midst 
of the vermiculites, h; the feldspar is more or less altered to kaolin, 
and often bears corundum, although most of it was found in the 
vermiculite zones, h represents the vermiculite zones carrying the 
corundum, which is in crystals and in rounded masses of crystals clus- 
tered together. Margarite sometimes accompanies it, and large masses 
■2];sn>^ 
Fig. 11. — Ideal vertical cross section of corundum in amphibolite at Hunters, Iredell 
County, N. C. 
made up almost entirely of these two minerals have been found on 
the surface in this region, c represents radiating borders of actino- 
lite that inclose large masses of what was once amphibolite, but what 
is now nothing but a mass of ocherous clay, bearing occasional needles 
of hornl)lende and scales of vermiculite. The outer portions, d, are 
dark-green amphibolite. 
CORUNDUM (emery) TN AMPHIBOLITE AT CHESTER, MASS. 
The most widely known occurrence of corundum in amphibolite is 
that of the emery at Chester, Mass., an elaborate description of wliich 
is given by Prof. B. K. Emerson ^' in his exhaustive work on the geol- 
ogy of old Hampshire County, Mass. 
« Bull. Oeol. Survey North Carolina No. 11, 1896, p. 59. 
"Mon. U. S. Geol. Survey, vol. 29, 1898. 
