amount of commercial feldspar of pottery grade still available at the locality.
The
feldspar is excavated by hand drilling and blasting, and after hand
sorting is hauled by wagons 3 miles to Littlefield station, where it is
sold to the Maine Feldspar Company and ground at that company's mill.
Gem tourmalines and minerals of value as cabinet specimens are not
encountered so frequently that it is profitable to work the deposit for
them alone. In 1906 the quarry force consisted of three men. The gems
and other valuable minerals obtained are marketed irregularly through
local collectors, and no estimate of their value is obtainable. The
feldspar output is a few hundred
tons a year.
CUMBERLAND COUNTY.
BRUNSWICK.
The relations between the granite and pegmatite in the town of Brunswick is well shown at the Woodside quarry, about 2\ miles
southeast of Hillside station. This is an old quarry, where granite for
flagging and underpinning has been obtained. The sheeting of the
granite here is very perfect and nearly horizontal.
On
the south wall of this quarry much pegmatite is associated with the
granite. Many of the pegmatite masses of lenticular or extremely
irregular form grade into the granite in the most gradual and complete
manner and are characterized by identical minerals. They differ from
the granite only in texture, and there can be no question that the two
rocks solidified practically contemporaneously from the same magma.
Other pegmatite dikes, however, distinctly cut the granite with sharp
contacts. The entire mincralogic similarity of this second type to the
pegmatite which grades into the granite leads to the belief that the
two types are genetically connected and that the intrusion of the
pegmatite masses that show sharp boundaries followed quickly on the
solidification of the granite which they cut.
Very
similar relations were observed at the Grant quarry, about 1-1/2 miles
east of Hillside and 3 miles west of Brunswick. This quarry has been
described by Dale.0
The
relations between the pegmatite and foliated rocks, which are probably
of igneous origin, is well exhibited in Brunswick village at a quarry
for road materials near the Lewiston branch of the Maine Central
Railroad. The folia in the rocks are in many places very straight and
regular for considerable distances. Much of the rock is a light-gray
schist which has the mineral composition of a hornblende granite.
The
slide of this rock examined shows an interlocking granular texture in
which most of the grains range from 0.15 to 0.60 milli-
<J Dale, T. N., The granites of Maine: Bull. U.S. Geol. Survey No. 313,1907, p. 76.
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