CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
181 
K. Pyroxene-andesite, west end of Butte Mountain, Plumas County. 
Prominent phenocrysts of pyroxene and minute ones of plagioclase, 
in a dark groundmass containing much globulitic matter. Analysis by 
W. F. Hillebrand, record No. 411. 
L. Pyroxene-andesite, south base of Burney Butte, Shasta County. 
Numerous small phenocrysts of plagioclase and a few of pyroxene, in 
a gray groundmass containing much amorphous matter. Analysis by 
R. B. Riggs, record No. 684. 
M. Hornblende-andesite, Tuscan Buttes, 7 miles east of Red Bluff. 
A few small phenocrysts or fragments of hornblende, in a groundmass 
consisting mainly of plagioclase and gray microlitic matter. Analysis 
by Hillebrand, No. 412. 
N. Hornblende-andesite, near Buntingville, Lassen County. A few 
phenocrysts of hornblende in a groundmass consisting mainly of small 
feldspars. Analysis by T. M. Chatard, record No. 413. 
O. Hornblende-andesite, northwest summit, head of Burney Creek, 
Shasta County. Inconspicuous plagioclase and, rarely, olivine, in a 
groundmass of plagioclase and pyroxene. Numerous dark spots are 
due to altered hornblende. Analysis by Riggs, No. 683. 
Rocks in this group dried at 105° before analysis. 
Si0 2 . 
Fe 2 3 
FeO_. 
MgO . 
CaO.. 
Na 2 0. 
H 2 0. 
Ti0 2 
PA- 
MnO 
SrO. 
BaO. 
Li 2 
SO, . 
55. 53 
17.63 
2.81 
3.59 
5.85 
8.74 
3.09 
.92 
1.24 
.56 
.21 
.08 
.06 
.02 
none 
100. 33 
62.44 
16.39 
4.66 
1.00 
2.65 
6.22 
3.16 
2.25 
1.02 
.31 
.05 
trace 
trace 
.03 
trace 
trace 
100. 18 
M. 
60. 93 
18.56 
2.68 
2.19 
2.37 
6.63 
3.79 
1.33 
.90 
.61 
.18 
.10 
.12 
.02 
none 
100. 41 
N. 
67.89 
17.29 
2.39 
.21 
.66 
3.01 
5.11 
1.69 
1.34 
.21 
.12 
.12 
.04 
.03 
100. 11 
60.04 
17.43 
5.39 
.53 
3.51 
6.65 
4.15 
1.24 
.90 
.49 
.04 
.08 
? 
.04 
trace 
trace 
100. 49 
