7 b THE GRANITES OF MAINE. 
medium-gray shade with a slight bluish tinge and very fine, even- 
grained texture, with particles ranging from 0.36 to 1.28 and, excep- 
tionally, from 0.18 to 2.5 mm. in diameter. Its minerals, in descend- 
ing order of abundance, are potash feldspar (microcline, orthoclase), 
smoky quartz, soda-lime feldspar (oligoclase), black mica, and white 
mica. The soda-lime feldspar is considerably altered to kaolin and 
a white mica and both feldspars often have intergrowths of quartz 
circular in cross section. The rock contains accessory apatite. It 
takes a fine polish. The specific gravity was reported by F. L. Bart- 
lett, of the Maine State assay office, as 2.627." It is free from pyrite. 
The quarry, first opened in 1886, now measures about 600 feet 
from northeast to soutlrwest by 100 feet across, and has a working 
face 55 feet high. It is not below the general surface at the road 
Fig. 5. — Structure" at Freeporl y 
swick. 
that passes in front of it. The drainage offers no difficulites. The 
stripping consists of 2 to 5 feet of loam and sand. 
Rock structure: The granite at the northeast end of the quarry is 
capped by about 5 feet of schist, and in its center the excavation, in 
proceeding in a direction parallel to the axis of the hill, has bisected 
an inclusion of this same schist 3 feet thick and about 40 feet long, 
dipping 35° E. to a point 30 feet below the surface of the granite. 
This schist inclusion is described on page 1 51. (See also PI. VII, 
B.) About 150 feet southeast of it is another inclusion of similar 
material. The presence of these inclusions necessarily involves some 
dead work and waste. The sheets are from 1 to 8 feet thick, increas- 
ing in thickness downward, and dipping up to 10° SE. and 10° NW. 
Joint courses are given in fig. 5. A forms the northeast wall of 
quarry and recurs every 20 to 50 feet; B, at southwest end of 
See Twentieth Ann. Kept. U. S. Geol. Survey, pt. 6, continued, 1898-9, p. 389. 
