Composition:

Petrographic Description:  An inequigranular rock with some foliation due to
the subparallel alignment of the long axes of feldspars and mica.  The
plagioclase is subhedral with albite and ocasionally Carlsbad twinning as
well.  The alkali feldspar anhedra can show grid-iron or Carlsbad twinning.
The nepheline anhedra often contain rounded inclusions of microcline, are
slightly turbid and frequently contain sericitic alteration along fractures.
Some of the nepheline contain abundant grains of a clear mica (muscovite) 
as an alteration product; in some cases the nepheline is almost completely
replaced by mica grains.  In addition, there are scattered subhedra of brown
biotite and less abundant anhedra of dark green (Fe-rich) biotite.  The
average modes were 45% plagioclase, 26% alkali feldspar, 3% muscovite
(including sericite) and 1.5% biotite.  No carbonate was seen in thin section,
but very weak spectral features indicate that some is present.

Microprobe Analysis:  The microprobe analysis revealed two modes of 
feldspar composition; Or94 and pure albite.  The nepheline analyses were 
consistent and indicated a composition equivalent to 17% kalsilite.

Chemical Analysis:
SiO2  59.85
CaO  0.16
TiO2  0.03
Na2O  9.69
Al2O3  22.07
K2O  5.18
Fe2O3  0.23
H2O  0.93
FeO  1.06
P2O5  0.0
MnO  0.02
MgO  0.04
TOTAL  99.26  (CO2 not analyzed)
