208 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
S. Biotite-hornblende-quartz-latite, Bullion ville, nearPioche. Ami- 
atose. Analysis by W. F. Hillebrand, record No. 1881. Contains 
abundant quartz, plagioclase, biotite, hornblende, and magnetite, in a 
glassy groundmass. 
T. Biotite-rhyolite, Meadow Creek Canyon. Liparose-toscanose. 
Analysis by Hillebrand, No. 1881. Contains quartz, orthoclase, some 
microcline, and a little biotite, in a glassy groundmass. 
U. Tordrillite, Meadow Creek Canyon. Liparose. Analysis by 
Hillebrand, No. 1881. Contains quartz, orthoclase, and plagioclase, 
with accessory biotite, in a glassy groundmass. 
V. Tordrillite, Sweetwater. Toscanost -liparose. Analysis by George 
Steiger, record No. 1883. Contains orthoclase and a little anorthoclase, 
in a feldspathic groundmass. 
W. Quartz-muscovite rock, Southern Klondike mine. Wear SR. 1 
ofriesenase. Anal} T sis hy Hillebrand, No. 2087. Consists mainly of 
quartz and muscovite. 
X. Another sample like W. SR. 1 <>f dargase. Same analyst, 
number, and description. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 105° . . . 
H 2 above 105 c 
Ti0 2 ... 
ZrO, 
C0 2 
P 2 5 - 
CI 
F 
S 
MnO 
SrO 
BaO 
LLO 
Less . 
s. 
63.08 
15. 74 
4.94 
.42 
1.38 
4.10 
3.16 
3.39 
1.70 
.98 
.71 
.02 
trace 
.17 
72.96 
12. 32 
.76 
.03 
.35 
2.18 
3. 24 
4.88 
.80 
1.63 
.11 
trace 
.92 
.10 
trace 
.07 
.04 
.10 
trace 
100. 00 
none 
trace 
trace 
trace 
trace 
100. 28 
u. 
74.00 
13.48 
1.73 
. 06 
.13 
.63 
4.63 
5.12 
.11 
.15 
.16 
.04 
trace 
.06 
trace 
trace 
none 
.05 
trace 
100..35 
V. 
74.30 
13. 29 
1.15 
.10 
.09 
.85 
3.75 
4.83 
.91 
.50 
.20 
none 
.07 
.03 
trace 
undet, 
none 
w. 
72.69 
« 13. 42 
.97 
.32 
.26 
1.97 
.21 
3.36 
2.36 
2.60 
undet. 
.97 
nndet, 
trace 
.25 
none 
present 
100. 07 
).38 
.10 
99.28 
x. 
75. 51 
"14.28 
1.09 
.38 
.28 
.34 
.20 
4.69 
f> 3. 36 
nndet. 
« Includes Ti0 2 and P 2 5 
6 Loss on ignition. 
undet. 
trace 
.20 
trace 
trace 
100. 33 
.08 
100. 25 
