40 CORUNDUM, ITS OCCURRENCE AND DISTRIBUTION. 
from a feAV feet to 10 or 12 feet, the average width of the emery 
being about 6 feet. Upon both 'sides of the emery there are usually 
developed thin seams of chlorite, varying from 1 inch to 6 inches or 
more in width. During the early history of the mine a seam of 
feldspar was encountered, about V2 inches w^ide, lying to the east of 
the emery and bordered on both sides by chlorite 3 or 4 inches Avide. 
There is also more or less chlorite developed in the mass of the ore 
body, which varies from an almost pure magnetite to an intimate 
admixture of magnetite and corundum. At the Sackett mine (de- 
scribed on p. 135) the corundum, of a bronze color and luster, is 
coarsely crystallized, giving the ore a porphyritic appearance. Some- 
times the corundum has crystallized out in blue and white crystals 
and in masses of a pound or two in weight. 
Dr. F. Von Camerlander '' describes the occurrence of corundum 
in the amphibolites of the n.orthwestern i)art of Austrian Silesia. It 
is found in Avhite or l)luis]i grams and masses up to the size of a 
hazelnut. CV)rundum with hercynite also occurs in the amphibolites 
at Konsberg, at the eastern foot of the Bohmerwald, in Bohemia. 
CORUNDUM IN ANORTHOSITE. 
The amphibolite, with its prevailing light-green amphibole and 
small amount of feldspar, that so frequently accompanies and inter- 
sects the peridotites of Clay County, N. C, and of Towns County, 
Ga., becomes in places highly feldspathic, and by the dwindling and 
disappearance of the amphibole it passes into the anorthosite facies 
at several localities. 
Anorthosites of this character, with more or less corundum in 
grains and irregular masses distributed through the rock, are found 
on the western slopes of Chunky Gal Mountain, Clay County, N. C, 
and in association with some of the amphibolites of the Buck Creek 
area in the same county. These rocks are always greatly subordinate 
in quantity to the associated amphibolites and peridotites, and never 
constitute more than an insignificant part of the outcrops. 
An occurrence that may be contrasted in some respects with the 
anorthosites of North Carolina and Georgia is found in South Sher- 
l)ro()ke, Lanark County, Ontario, Canada, vv^here the rock is composed 
hu'gely of basic plagioclase and a little green hornblende, but is 
somewhat more basic than the typical Canadian anorthosite. The 
corundum occurs sparingly in the rock in crystals of almost uniform 
size, about half an inch in length. Their color varies from light gray 
to almost white, and sometimes to light pink. 
Verhandl. K.-k. geol. Reichsanstalt, Wien, 188G, p. 356. 
