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134 GEOLOGY OF NEW YORK CITY
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ported this mineral before Levison's find. Found since by Alfred C. Hawkins and Edgar T. Wherry.
Chrysotile, in serpentine.
Cleavelandite, lamellar albite, reported by Cozzens in boulders at Corlear's Hook.
Coccolite, reported (a granular pyroxene usually disseminated in limestone, characteristic of the Adirondacks).
Copper Alum (Copper Sulphates), reported by Hidden as " precipitating copper on a knife blade in a weak solution."
Colombite, the
niobate and tantalate of iron and manganese, beautiful doubly
terminated black crystals in the Kunz collection, from Fort George,
associated with l?eryl.
Crichtonite, phase of menaccanite; reported.
Datolite, reported in trap; drift.
Dolomite, the
carbonate of calcium and magnesium, the so-called dolomite of
Kingsbridge, is a magnesian limestone, and is abundant at the north end
of the island, holding sporadic occurrences of pyrite, chalcopyrite,
rutile, chlorite, tremolite, quartz, and white pyroxene. Coarse pink,
nodular streaks at Mott Haven. As Chamberlin remarks, good crystals
unusual.
Dumortierite, basic,
aluminum silicate, sometimes containing boric acid. This mineral is
sparingly developed in the United States. It is an unusual mineral
anywhere. Formerly, as found on Manhattan Island, it was thought to be
a blue tourmaline (indicolite). It was first discovered near
Beaunan, France. It occurs there in fine grains or needles enclosed in
pegmatite, and associated with gneiss. The Harlem specimens were
separated from tourmaline by Riggs, and it was supposed to be a new
mineral. Later E. S. Dana identified it. It is found also at Clip,
Arizona, and in San Diego County, California. W. E. (Ford found boric
acid in specimens from all three localities, the boric acid in the
Harlem specimen being 6.14 per cent.; gravity of the same, 3.211 to
3.302. Found in red granite extending from 123d Street and 4th Avenue
to Madison Avenue and 116th Street; usually in thread-like bunches
penetrating orthoclase or oligoclase, rarely in quartz or mica.
Epidote, a
silicate of aluminum, iron, and calcium, forms some of the pleasing
mineral combinations on the island. It occurs in very pretty
crystallizations of dark green prisms, associated with and agreeably
complementary to light pink orthoclase on gneiss surfaces. A singular
association of epidote and glassy orthoclase is exhibited by Dr. Kunz
from Columbus Avenue.
Very good specimens have been taken from the region about
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