the
pegmatite contacts studied. It has resulted in the abundant development
of prisms of cinnamon-brown tourmaline from one-fourth to one-half inch
long and one-sixteenth to one-eighth inch in diameter in certain of the
more muscovitic layers. More biotitic portions present a mottled
appearance, due to the occurrence of the biotite, in irregular
aggregates one-eighth to one-fourth inch in diameter. Under the
microscope this mottled rock is seen to consist of brown biotite,
light-green hornblende, quartz, labradorite, titanite, magnetite, and
apatite, the latter in small hexagonal prisms filled with a cloud of
very minute inclusions. The tendency to aggregation of the biotite,
hornblende, titanite, and magnetite gives the mottled appearance, the
white intervening areas being largely quartz and labradorite. The
mineral grains of this rock are interlocking and the texture granular
and indistinguishable from that of an igneous rock. Field relations
show, however, that the rock is a phase of the sedimentary schist wall
rock which has undergone complete recrystallization.
It
is notable that neither of the metamorphosed phases of the wall rock
described above contains any minerals except the common ones, quartz
and muscovite, that are characteristic of the neighboring pegmatite.
The tourmaline, of the schist is brown and wholly dissimilar from any
found in this or any other pegmatite of the State. Additions, if any,
received by the wall rock from the pegmatite during the complete
recrystallization of the former were ionic in their character, the
minerals characteristic of the pegmatite, with the possible exception
of quartz, not being added as such to the intruded rock.
The
quarry was opened in about 1901 by Oliver Gildersleeve and has been
worked for four seasons. About 250 tons of mica is reported to have
been mined in 1905. The quarry was idle throughout 1906, in which year
the writer visited it, and so far as is known has not reopened since.
Steam drills were employed and sheds built for hand picking the mica,
which was packed in 100-pound bags and hauled by team 7 miles to Frye,
on the Rangeley division of the Maine Central Railroad. From Frye it
was shipped to a grinding mill at Gildersleeve, Conn. About 1,000 tons
in all are reported to have been shipped. The quantity of scrap, mica
still available at this quarry is large, but there is no plate mica,
nor is it probable that further excavation will disclose any. It is
doubtful if at present the property can be profitably exploited for
scrap mica in view of the fact that the refuse cuttings from plate mica
properties appear able to meet entirely the present demand for scrap
mica. 63096°—Bull. 445—11------7
