Name:   Biotite Granite

Geologic Name:  Woodbury Granite

Reference:  Dale, T.N., The granites of Vermont:  U.S. Geol. Survey Bull. 404, pp. 11,
12-14, 24, 93-105, 1909.

Microscopic characters:  Hypautomorphic-granular textrue.  The feldspar content includes
microcline showing lattice structure, orthoclase and sodic plagioclase (albite-oligoclase) 
somewhat altered to sericite.  The plagioclase shows zonal structure.  Quartz occurs in
large clear grains or in micropegmatitic intergrowth with feldspar.  Biotite, which is 
sometimes fresh and sometimes partially altered to chlorite, and muscovite complete
the list of essential minerals.  The accessories are apatite and zircon crystals, irregular
grains of titanite and some epidote.