240 
ANALYSES OF ROCKS, IT. S. GEOLOGICAL SURVEY. [no. 228. 
12. MARIPOSA COUNTY. 
Rocks collected by H. W. Turner, and partly described in his papers 
in the 14th and 17th Annuals. Additional data supplied by Turner. 
A. Soda-granulite or aplite, about 4 miles west of Mariposa. Mari- 
posose. See 17th Ann., Part I, p. 721. Contains plagioclase (albite?) 
and micropegmatite, with less epidote, quartz, sphene, and apatite. 
Analyses by W. F. Hillebrand, record No. 1461. P. R. C. 748. 
B. Micropegmatite, Agua Fria Creek. Lassenose. See 17th Ann., 
Part 1, p. 691. Contains quartz, plagioclase, brown mica, epidote, and 
a little iron ore. Analysis by Hillebrand, No. 1461. P. R. C. 746. 
C. Soda-granite-porphyry, Merced River, below the mouth of the 
north fork. Lassenose. Published in 17th Ann. Contains feldspar, 
largely albite, hornblende, muscovite, abundant epidote, apatite, and 
a little iron ore. Analysis by George Steiger, record No. 1573. 
P. R. C. 774. 
D. Granite-porphyry, about one-fourth of a mile north of Lake 
Tenaya, Yosemite National Park. Toscanose. See 14th and 17th 
Annuals. Contains orthoclase, quartz, plagioclase, and biotite, with 
a little iron ore and sphene. Analysis by Hillebrand, record No. 
1482. P. R. C, 726. 
E. Granite, west of Lake Tenaya, Yosemite National Park. Lassen- 
ose. See 14th and 17th Annuals. Contains quartz, orthoclase, plagi- 
oclase, and biotite, with some hornblende, iron ore, sphene, and 
apatite. Analysis by Hillebrand, No. 1482, P. R. C. 725. 
A. 
B. 
c. 
D. 
E. 
Si0 2 
74.21 
14. 47 
. 35 
.50 
.28 
1.71 
7.62 
.10 
.15 
.23 
.30 
.07 
none 
trace 
none 
trace 
73.18 
L3.66 
.21 
2.24 
.93 
2.10 
3. 70 
2.72 
.10 
.57 
.25 
.09 
.07 
trace 
.10 
trace 
.17 
71.88 
15. 57 
1. 07 
. 30 
.68 
2.03 
5.81 
1.80 
.11 
.68 
.17 
.08 
none 
.08 
.02 
none 
none 
72. 48 
14. 06 
. 89 
1.05 
.62 
2.17 
3. 30 
4.75 
.16 
.35 
.28 
.09 
trace 
trace 
.08 
trace 
66.28 
ALA 
Fe 2 0, 
16.03 
1.80 
FeO 
1.88 
MgO 
1.12 
CaO 
3.75 
Na 2 
4. 10 
K 2 
3.49 
H 2 Oat 110° 
.10 
H.-0 above 110° 
.39 
Ti0 2 
54 
PA 
30 
MnO 
.05 
SrO 
BaO 
08 
Li 2 
C0 2 
99.99 
100. 09 
100. 28 
100. 28 
99.91 
