CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
217 
3. BASALTS. 
The quartz-basalts are described by Diller in Bull. 79. That from 
Mitylene was analyzed for comparison with the Cinder Cone series. 
A. Quartz-basalt, Cinder Cone, 10 miles northeast of Lassen Peak. 
Andose. Contains plagioclase, pyroxene (mostly hypersthene), olivine, 
quartz, and much unindividualized base; the latter about 25 percent. 
Magnetite is also present; augite occurs sparingly. Analysis by W. F. 
Hillebrand, record No. 407. P. R. C. 101. Also described in Bull. 
150, p. 252. 
B. Volcanic bomb from quartz-basalt, Cinder Cone. Andose. 
Analysis by Hillebrand, No. 665. 
C. Lapilli from quartz-basalt, Cinder Cone. Andose. Analysis by 
Hillebrand, No. 667. P. R. C. 96. Also described in Bull. 150, p. 249 
and 791. 
D. Volcanic sand, one-half mile northeast of Cinder Cone. Andose 
Analysis by Hillebrand, No. 663. P. R, C. 792. 
E. White pumiceods inclosure from quartz-basalt, Cinder Cone. 
Alsbachose. Analysis by Hillebrand, No. 664:. Mainly glass. P. R. C. 
793. 
Rocks dried at 100° to 110° before analysis. 
Si0 2 .. 
A1 2 3 . 
Fe 2 3 . 
FeO.. 
MgO . 
CaO.. 
Na 2 0. 
K 2 0.. 
H 2 0. 
Ti0 2 . 
p 2 o 5 . 
O 2 o 3 
MnO. 
SrO. 
BaO. 
Li 2 
A. 
r>7. lt> 
It). 45 
1.67 
4.72 
6.74 
7.65 
3.00 
1.57 
.40 
.60 
.20 
.10 
trace 
.03 
none 
100. 38 
B. 
56.70 
15. 75 
1.29 
5.32 
7.16 
7.67 
3.36 
1.56 
.30 
.65 
.20 
trace 
.19 
trace 
.03 
trace 
100. 18 
56. 53 
17.50 
1.35 
5.03 
5.94 
8.07 
3.51 
1. 55 
.27 
.54 
.15 
trace 
.12 
trace? 
trace 
trace 
100. 56 
D. 
55.93 
17.34 
1.50 
5.20 
7.29 
8.04 
3.32 
1. 35 
.26 
undet. 
undet. 
undet. 
(?) 
(?) 
(?) 
100. 23 
79.49 
11.60 
.33 
.49 
.09 
1.64 
4.04 
1.52 
.68 
undet. 
undet. 
none 
(?) 
(?) 
(?) 
►.88 
