106 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[NO. 228. 
2. SEPULCHRE MOUNTAIN. 
Rocks described by Iddings, 12th Ann., p. 633. Also in Bull. Phil. 
Soc. Washington, vol. 11, p. 210, and in Mon. XXXII, Pt. II. 
A. Pyroxene-andesite. Tonalose. Essentially composed of augite, 
hypersthene, and plagioclase. Analysis by J. E. Whitfield, record 
No. 923. 
B. Pyroxene-andesite. Andose. Composition like A. Analysis 
by Whitfield, No. 923. 
C. Hornblende-andesite. Andose. Essentially plagioclase and horn- 
blende. Analysis by Whitfield, No. 922. 
D. Hornblende -pyroxene-andesite. Tonalose. Contains augite, 
hypersthene, plagioclase, and hornblende. Analysis by T. M. 
Chatard, record No. 712. 
E. Hornblende-pyroxene-andesite. Tonalose. Minerals as in D, 
with magnetite also. Analysis by Chatard, No. 712. 
Si0 2 
A1A 
Fe 2 3 .--- 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 105 < 
105° 
Ti0 2 
F 2 5 
OA 
MnO 
BaO. 
SrO. 
Li 2 
S0 3 . 
01... 
55. 83 
17. 11 
4.07 
3. 75 
5. 05 
7.40 
2.94 
1.71 
1.28 
1.05 
.21 
none 
trace 
none 
100. 40 
57.17 
17.25 
2. 48 
4. 31 
4.83 
6.61 
3.44 
2.03 
1.20 
1.03 
.05 
trace 
trace 
trace 
100. 40 
55. 92 
17.70 
3.16 
4.48 
4.34 
5.90 
4.08 
2.24 
1.42 
.94 
.18 
trace 
.09 
trace 
none 
100. 45 
56. 61 
L3.62 
5. 89 
2. (id 
5. 48 
6.61 
3. 13 
2.71 
1.20 
1.07 
.79 
.06 
.05 
.35 
. 14 
trace 
(?) 
100. 31 
60. 30 
16.31 
4.35 
1.41 
2.39 
5.62 
3.99 
2.36 
.64 
1.86 
.76 
.20 
trace? 
.13 
.15 
trace 
10 
100. 57 
