68 
CORUNDUM IN THE UNITED STATES. 
[BUI,I,. 180. 
average depth of 20 feet for the entire distance. Emery varying in 
width from 3 to 20 feet was encountered throughout nearly the entire 
length of the cut. 
This mine was reopened in 1899, a shaft 87 feet deep having been 
sunk on the vein near the southern end of the cut and drifts run out 
from this. Margarite is the most conspicuous accessory mineral, and 
specimens that can rarely be excelled have been found here. 
Continuing nearly half a mile to the north on the vein and near 
the top of the mountain is the Melvin mine. There is a shaft here 
40 feet deep, from which drifts are being run. This shaft is but 
1,250 feet from the head of the upper tunnel of the Old mine, the next 
one to the north. It is 
iu this Old mine that the 
most extensive work has 
been done. Fig. 14 is a 
cross section of its under- 
ground workings. The 
mouth of the lowest tun- 
nel is but 8 feet above 
Walker Brook and 75 feet 
to the south of it. As is 
seen from the diagram, the 
emery does not occur con- 
tinuously throughout the 
vein, but in pockets or 
chimneys which dip into 
the vein about 30° N. 
From the work already 
done these seem to hold 
this direction rather con- 
stantly, so that the pock- 
ets can be approximately 
located at a given depth. 
It was in the first chimney 
of emery (see map, fig. 13) 
for which this mine is noted, 
Fig. 13.— Map showing the location of the emery deposit 
at Chester, Mass. 
that the beautiful specimens of diaspoi 
were found. 
North of Walker Brook and about 500 feet from the Old mine 
is the Macia mine, where a small amount of surface work has been 
done. Near the head of a small ravine a tunnel was started on the 
west of the vein to intercept it, but work was discontinued before the 
vein was reached. 
The next opening is near the highest point of the vein on the 
eastern slope of Gobble (North) Mountain, about three-fourths of a 
mile north of the Macia mine, and is known as the Sackett mine. At 
this part of the vein there was a considerable quantity of magnetite 
