Name:   Monzonite

Geologic Name:  None

Reference: Cross, C.W., and Howe, E., Description of the Silverton
Quadrangle: U.S. Geol. Survey, Geol. Atlas, Silverton folio (No. 120),
1905.

Microscopic characters:   Hypautomorphic-granular texture.  Orthoclase
and plagioclase crystals are developed to a considerable size.  The
orthoclase is clouded with secondary kaolin while the plagioclase is
altered to sericite and epidote.  Biotite crystals are partly altered to 
chlorite, with epidote and titanite as by-products.  Hornblende crystals
are still quite fresh.  A granular aggregate of quartz, orthoclase and plagioclase
fills the space between the larger crystals.  Magnetite is quite abundant 
while small crystals of apatite and grains of zircon are less common.
