Name:   Amygdaloidal Basalt

Geologic Name:  None

Reference:  Butler, B.S., Burbank, W.S., and others, The copper deposits of
Michigan: U.S. Geol. Survey Prof. Paper 144, p. 26-47, 1929.

Microscopic characters:  The groundmass is composed of small lath-shaped
plagioclase crystals with interstitial chlorite and in it are grains of augite and
large crystals of labradorite.  The augite grains are partially altered around the
edges to hematite and an opaque dust-like material.  There are circular or oval
ares consisting of clear lath-shaped plagioclase with a small amount of 
interstitial augite.  The amygdules are filled with epidote, granular quartz, 
calcite, and chlorite.