Composition:

Petrographic Description:  A hypidiomorphic rock with moderately well- 
developed gneissoid foliation due to the subparallel alignment of subhedral 
green hornblende, which is partly replaced by biotite.  The anhedral 
plagioclase is frequently zoned gradationally and often shows either 
Carlsbad or albite twinning.  The cores of most of the feldspars are slightly 
sericitized and in a few regions of the sample are heavily sericitized.  
Epidote was a common accessory mineral, much less commonly apatite.  
The modal analyses gave: 5l% plagioclase, 39% hornblende, 3.4% biotite, 
0.8% epidote, with the remaining percentages composed of sericite and 
apatite.

Microprobe Analysis:  The plagioclase composition was rather 
homogeneous, ranging from An40 to An48 (andesine).  However, some 
grains were quite heterogeneous.  One grain had a composition of Or62 at 
the border where Ab dropped to about 10%; another feldspar was 
heterogeneous as well, with a composition ranging from 0.5% to 12% CaO.  
The hornblende analysis revealed a homogeneous composition equivalent to 
pargasite.

Chemical Analysis:
SiO2  49.81
CaO  9.48
TiO2  1.27
Na2O  3.86
Al2O3  19.35
K2O  1.18
Fe2O3  2.38
H2O  1.41
FeO  5.34
P2O5  0.08
MnO  0.08
MgO  6.16
TOTAL  100.4
