CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
87 
YELLOWSTONE NATIONAL PARK AND THE ABSAROKA RANGE. 
1. ELECTRIC PEAK. 
Rocks described by Iddings in 12th Ann. , p. 577. Also in Bull. Phil. 
Soc. Washington, vol. 11, p. 206. For analyses O, P, see Mon. XXXII, 
Pt, II. 
A. Pyroxene-mica-diorite. Contains augite, hypersthene, plagio- 
clase, quartz, biotite, hornblende, magnetite, and apatite. Analysis by 
J. E. Whitfield, record No. 830. P. R. C. 94. 
B. Pyroxene-mica-diorite. Same minerals as under A. Analysis by 
Whitfield, No. 921. 
C. Pyroxene-mica-diorite. Like A and B. Analysis by W. II. 
Melville, record No. 1231. 
D. Pyroxene-porphyry. Contains augite, hypersthene, biotite, mag- 
netite, plagioclase, and quartz. Analysis by Whitfield, No. 830. 
E. Quartz-pyroxene-mica-diorite. Contains biotite, hornblende, 
augite, hypersthene, magnetite, plagioclase, orthoclase, and quartz. 
Analysis by Melville, No. 1231. 
Si0 2 
ALA 
Fe 3 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl00° 
H 2 above 100° . 
Ti0 2 
PA _ 
MnO 
NiO 
so 3 
CI. 
A. 
56.28 
14.23 
4.69 
4.05 
6.37 
7.94 
2.98 
1.23 
.93 
.84 
.40 
.16 
.01 
trace 
.17 
100. 28 
B. 
58. 05 
18.00 
2.49 
4.56 
3.55 
6.17 
3.64 
2.18 
.86 
1.05 
.17 
none 
none 
.07 
trace 
100. 79 
61.22 
16.14 
3.01 
2.58 
4.21 
5.46 
4.48 
1.87 
.04 
.40 
.61 
.25 
trace 
.09 
100. 36 
57.38 
16.86 
2.49 
5.17 
5.51 
7.32 
3.33 
1.45 
.42 
trace 
trace 
trace 
.39 
.21 
.17 
100. 70 
64.07 
15.82 
3.40 
1.44 
3.39 
4.43 
4.06 
2.27 
.10 
.42 
.45 
.18 
trace 
.05 
100. 08 
