76 PEGMATITES AND ASSOCIATED ROCKS OF MAINE.
but
containing numerous small crystals of black tourmaline. In the larger
pit there is a small amount of feldspar of commercial grade at its
northwest end, but in the smaller pit and in the unopened ledge near
the pits black tourmaline is so intimately and abundantly associated
with the feldspar as to render most of the latter valueless for pottery
purposes under present commercial conditions. The coarsest and most
highly feldspathic portion of the deposit as exposed in the larger pit
contains some clevelandite and granular lepidolite and a few colored
tourmalines of pink and green tints, which are translucent to opaque. A
few small pockets occur and several less than a foot in diameter were
exposed at the time of the writer's visit. In some of the pockets a few
transparent tourmalines of gem quality were found during the mining
operations. South of the workings the ledge shows very little feldspar
of pottery grade and within 200 feet there begins to be some admixture
of schist with the pegmatite.
Muscovite
has been saved during the mining, but most of it is what is known as
wedge mica and would be valueless except as a source of ground mica.
Biotite or black mica is very rare, black tourmaline being the
principal iron-bearing impurity.
The
trend and exact limits of this deposit could not be determined, but
there is every indication that the supply of feldspar suitable for use
in the pottery trade is very small, most of the material showing too
great an abundance of black tourmaline. An examination of the whole
coast of the hill south of the pits showed no spar or other minerals of
commercial grade. Even if the mica and tourmalines were marketed as
accessories it is probable the deposit could not be made to pay.
No
mining machinery was installed at this locality. The feldspar was
hauled 5 miles, mostly down grade, to South Paris, on the Grand Trunk
Railway. Only a few tons of it was shipped, and much spar now lies in
stock piles at the quarry.
NEWRY.
The rocks of Newry were studied only in the extreme northeast corner of the town at a quarry formerly operated for gem tourmalines.
The
Dunton tourmaline mine is situated near the summit of a considerable
hill that rises back of the farm of Joshua Abbott, about 1 to 1-1/2 miles
west of the wagon road between North Eumford and South Andover. It was
operated in the summers of 1903 and 1904 by H. C. Dunton, of Eumford
Falls.
The
pegmatite mass appears to be sill-like in form, with an average
thickness of about 20 feet and a dip of about 40° SE. The wall rock has
been intensely altered, but whether this is largely due to contact
metamorphism by the pegmatite is uncertain. It is a light-green rock,
exceedingly tough, and is composed largely of muscovite, actin-
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