120 ANALYSES OF ROOKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
5. MISCELLANEOUS ROCKS. FIRST GROUP. 
Collected and investigated by Arnold Hague and J. P. Iddings. 
A. Black obsidian, Obsidian Cliff. Liparose. Described by Iddings, 
7th Ann. Contains microlites of augite and magnetite, with traces of 
quartz and feldspar. Analysis by J. E. Whitfield, record No. 224. 
B. Red obsidian, Obsidian Cliff. Alaskose. Described by Iddings, 
7th Ann. Like A, with ferric oxide replacing magnetite. Analysis 
by Whitfield, No. 223. 
C. Obsidian, east of Willow Park. Lassenose. Black and opaque. 
Described by Iddings, Bull. Phil. Soc. Washington, vol. 12, p. 204. 
Analysis by Whitfield, No. 222. 
D. Lithoidite, Obsidian Cliff. Lassenose. Described by Iddings, 
Bull. 150, p. 153. Contains quartz and sanidine, with a little magnet- 
ite and augite. Analysis by Whitfield, No. 425. P. R. C. 62. 
E. Rhyolite, Upper Geyser Basin. Ziparose. See Iddings, Bull. 
Phil. Soc. Washington, vol. 12, p. 204. Analysis by F. A. Gooch, 
record No. 114. 
F. Rhyolite, Tower Creek. Toscanose. See Iddings, Bull. Phil. 
Soc. Washington, vol. 12, p. 204. Analysis by Gooch, No. 115. 
A. 
B. 
c. 
D. 
E. 
F. 
Si0 2 
74.70 
L3.72 
1.01 
.62 
.14 
.78 
3. 90 
4. 02 
.62 
none 
none 
trace 
75. 52 
14.11 
1.74 
.08 
.10 
.78 
8.92 
3. 63 
.39 
none 
72. 59 
13. 47 
1.58 
1.32 
1.05 
2.12 
4.63 
2.52 
.18 
.52 
75. 50 
13.25 
1.02 
.91 
.07 
.90 
4.76 
2. 85 
.41 
none 
none 
none 
.06 
.32 
70.92 
13.24 
3. 54 
.66 
.23 
1.42 
4.28 
4.25 
.57 
.16 
.18 
.14 
none 
71.85 
A1 2 3 
13. 17 
Fe 2 3 
FeO 
2.17 
1.34 
MgO 
.63 
CaO 
2.25 
Na 2 
4.06 
K 2 
3.89 
H 2 
.43 
Ti0 2 
.43 
P 2 5 
14 
MnO 
none 
none 
.12 
Li 2 
so 3 
FeS 2 
.40 
.11 
.26 
99.91 
100. 38 
100. 24 
100. 05 
100. 59 
100. 48 
