Limonite, hydrated
sesquioxide of iron, bog-ore, common on low-grounds; " in globular
forms resembling shot. 55th Street, 6th and 7th Avenues, and elsewhere"
(Chamberlin).
Magnetite, proto-sesquioxide
of iron, in solid cubical black blocks, 170th Street and Eleventh
Avenue; "crystallized in lamellar and radiated forms, between leaves of
muscovite (the magnetic markings), Riverside Park and elsewhere"
(Chamberlin) ; found also in veins of quartz.
Malacolite, a
white pyroxene, quite frequently found in the dolomite (Kingsbridge
limestone), and sometimes stoutly developed in thick-bent and
fractured crystals (E. C. Eckel): usually flat, yellowish-white,
crumbling prisms.
Malachite, green carbonate of copper, stains, blotches, and colorings, in gneiss and granite, from oxydized chalcopyrite or bornite.
Manganese Oxides (Wad, Bog-manganese, Psilomelane, etc.).
Mr. Yeshilian has taken some pains to examine black, burnt-looking
exposures of the schist, especially on Washington Heights at 146th
Street, between Broadway and Amsterdam Avenue. These he found to be
unquestionably accumulations and crusts of manganese oxides. He reports
finding a deposit of it about 20 feet square and one foot deep on the
site of the new Orphan Asylum between Amsterdam and Convent Avenues. He
remarks it is not far from the hornblende schist in its vicinity.
Marcasite, sulphide
of iron, reported from excavations for addition to Metropolitan Museum
of Art, " in reniform and globular masses " (Chamberlin).
Marmolite, a slickensided and indurated serpentine, 63d Street and nth Avenue.
Menaccanite, the
oxide of iron and titanium, is found in flat black plates of
considerable size in granite and on gneiss. The form hystatite
(washingtonite), with a low percentage (15-16) of titanium, is probably
found in thick plates, and may include nearly all the ilmenite on the
island.
Microlite, an
isometric calcium tantalate containing also, with fluorine, a cluster
of rare bases: " small octahedrons in oligoclase, 39th Street, 6th and
7th Avenues" (Hidden).
Molybdenite, the
sulphide of molybdenum, a graphite-looking mineral, is found in
excavations in flat plates or crystals, on gneiss, and quartz in veins.
Mr. F. A. Camp reports that molybdenite was seen in several veins (20
to 30) in the amphibolite dike east of Convent Avenue in " fine clear
sheets " ; the veins were made up of quartz, orthoclase, and garnets.
