QUARRIES IN WALDO COUNTY. 
153 
[uarrv, gives it an ultimate crushing strength of 32,635 pounds per 
qua re inch. 
The quarry was opened before 1837 on the east side of the moun- 
ain. The later opening on the top measures 1,000 feet by 500, with 
depth ranging up to 25 feet, There is no drainage problem nor 
tripping. 
Rock structure: The sheets, from 6 inches to 15 feet thick, dip 
rently northwest and east from the summit of the dome, and below, 
kd the east side, they dip 45°, as shown in PL III, B. Some of the 
ipper sheets taper out at the sides. (See, further, p. 34.) Vertical 
oint courses and dike courses are shoivn in fig. 34. The rift is hori- 
zontal and the grain vertical, with course N. 80°-85° W. Some of 
he joint surfaces are coated with chlorite and pyrite of secondary 
irigin. A dike of quartz monzonite, 10 feet thick, dips 40° E. 
V\ 
G . 34.. Structure at the Mosquito Mountain quarry, Frankfort. 
this is described on page 48. There are branching dikes of aplite 
from 1 to 3 feet thick. At the south end of the quarry is a diabase 
iike 7 feet thick, crossing from east to west. This is described 
jnore fully on page 48. Somewhat abundant knots up to 12 inches 
it diameter and of circular or elliptical cross section occur. Sap 
Measures up to 12 inches in thickness in the upper sheets, but is 
!bsent lower down. 
The plant consists of 7 derricks and 3 engines, 1 traveling steam 
rane, 1 compressor (with capacity of 640 cubic feet of air per 
l^inute), 2 steam drills, 10 pneumatic plug drills, 3 surfacers, and 25 
pneumatic hand tools. 
Transportation is effected by about 7,000 feet of track, and gravity 
ars from quarry to cutting shed and wharf on Marsh River (South 
branch stream), which admits schooners of 14 feet draft. 
