202 
ANALYSES OF ROOKS, U. S. GEOLOGICAL SURVEY. 
[bull. 168. 
K. Wollastonite-gneiss, north fork of Mokelumne River. Mainly 
wollastonite, but garnet, quartz, and sphene are also present. P. R. 
C. 766. 
L. Melaphyr-tuff, altered basalt, west of Jackson. Contains augite 
and plagioclase, with secondary quartz, chlorite, and chrysotile. 
Originally glassy in part, but devitrified. See 14th Ann. P. R. C. 722. 
M. Reddish-brown mica separated from pyroxenic-gneiss, north fork 
of Mokelumne River, about 1 kilometer above mouth of Bear River. 
Described by Turner in Amer. Journ. Sci., 4th series, vol. 7, p. 294. 
Analysis by William Valentine, record No. 1736. 
K. 
L. 
M. 
SiO, 
50.67 
6.37 
.31 
.50 
.58 
40.34 
.14 
.22 
.08 
.31 
.20 
none # 
none 
trace 
none 
none 
none 
49.24 
14.79 
1.36 
8.00 
6.89 
10.74 
2.76 
.88 
.20 
2.97 
.96 
.17 
36.62 
14.37 
4.04 
17.09 
9.68 
1.48 
.45 
8.20 
.90 
3.26 
3.03 
none 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 110° 
H 2 above 110° 
Ti0 2 . 
P. 2 0, 
NiO 
MnO 
.18 
trace 
.04 
trace 
.40 
trace 
.33 
trace 
.10 
SrO 
BaO 
Li 2 
F 
CO., 
.52 
.90 
Less ...-. 
100. 24 
100. 08 
99.95 
.04 
99.91 
