142 
THE GRANITES OF MAINE. 
Rock structure: The geological relations at this quarry are of no 
little interest, as will be seen by the references to it on pane- 15, 45, 
and by PL IX, A, and fig. i >( .>. The granite is here in contact with 
the schist mass, which originally covered it and winch at all the other 
Maine quarries, except those at Freeport and Round Pond, has been 
removed. On the northeast side of the quarry a mass of schist 
striking N. 72° W. and dipping 45° X. 72° E. and also 90°, overlie. 
the granite, which sends small dikes into it. The contact between 
the two rocks appears at the east corner of the quarry and is shown 
in PI. IX. .1. At the southwest end of the quarry (wo schist masses 
•ire partially included in the granite, and a large pegmatite mass in- 
tervenes, as is shown roughly in fig. 29. The sheets, from 1 to 7 feet 
thick, lie horizontal and dip 5° W. in the upper part of quarry. 
The joint -md dike courses are shown in fig. 30. Joints A dip 60° 
Pig. 29. Schist inclusions al southwesl cud of Waldoboro quarry. Total bright, 4. r > feet. 
Th<> coarse material, between the two inclusions, i- pegmatite. The liner is muscovite- 
biotite granite. 
SE., and form both longitudinal walls of the quarry, a heading on 
I he northwest side, and recur at intervals of 40 feet. Joints B dip 
85° N. and recur at intervals of 100 feet. The rift is horizontal and 
the grain i^ vertical, with course X. 60° W. Pegmatite dike <i. 51 
inches thick, dips 60 SE.; dike A. 12 inches thick, dips S. 60 Wl 
at an angle of l.V . A dike of aplite, an inch thick, dips 45° XK. 
Sap is confined to the upper sheets. Knots are vrv exceptional. 
That the granite is under compressive strain is shown bv the clos- 
ing up of the channels when the cores are taken out, and also by 
spontaneous north to south Assuring. 
The plant consists of 3 derricks, operated by 3 engines (one of 
these derricks is 108 feet 4 inches high with a 90-foot boom), 3 over- 
head traveling cranes (of 3 and 2 tons capacity), 1 compressor (ca- 
