128 
THE GRANITES OF MAINE. 
The plant consists of 2 derricks, 1 hoisting engine, 1 steam drill, 
and 1 steam pump. 
Transportation is effected by cars and horsepower on a track one 
•half mile long to wharf near Birch Point. 
The Long Core quarry is in the town of Tenants Harbor, on Long 
Cove, St. George River, about 13 miles southwest of Rockland. 
Operator, Booth Brothers & Hurricane Isle Granite Company; 
offices, Rockland, Me., and 207 Broadway, New York. 
The granite is a biotite-muscovite granite of bluish medium-gray 
color and of fine to medium even-grained texture like that of th 
Clark Island quarry, described on page 125. Tests of its compressiv 
Fig. 
Structure at Long Cove quarry, Tenants Harbor. 
strength made by the Columbia School of Mines are reported by th 
firm to have shown an ultimate crushing strength of 22,000 pound 
per square inch, but the original report of these tests has beei 
misplaced. 
The quarry, opened about 1873, measures about 1,000 feet from nortl 
to south by 500 feet from east to west, and ranges in depth from 20 
to 75 feet, averaging about 40 feet. Its drainage involves pumpinj 
with 1-inch pipe during rainy season. This is the only quarry ii 
the State in which tunneling is resorted to in the use of explosives 
(See p. 71.) 
Rock structure: The sheets, from 6 inches to 13 feet thick, an 
horizontal, or dip 10°. Joints and dike courses are shown in fig 
21. A recurs at intervals of from 2 to 30 feet, B dips 25°, C dip 
05° N. E. The east end of the quarry is much broken up by the 
closeness of joints A and the thinness of the sheets for a considerable 
distance below the surface. The rift is vertical with N. 80°-90° W 
course. There is a horizontal dike of pegmatite up to 9 inches thick 
