Name:  Anorthosite 

Geologic Name:  Adirondack anorthosite (Mount Marcy type)

Reference:  Kemp, J.F. and Ruedemann, R., Geology of the Elizabethtown and
Port Henry quadrangles: New York State Mus. Bull. 138, p. 27-37, 1910.

Microscopic characters:  Granular rock consisting almost entirely of labradorite
showing albite and pericline twinning.  There is a small amount of hornblende
altering to chlorite and a few grains of titaniferous magnetite.  Flakes of sericite
and stringers of calcite occur as secondary minerals.
