IGNEOUS AND CRYSTALLINE ROCKS. “141 
Kk L M. N oO 
67.89 60. 04 
17.29 17. 43 
2.39 5.39 
21 - 53 
66 3. 51 
3.01 6.65 
5.11 4.15 
1.69 1.24 
1.34 - 90 
21 49 
12 04 
12 - 08 
04 (?) 
- 03 04 
: eee trace 
Pucege trace 
100.11 | 100. 49 
P. Hypersthene andesite, 1 mile west of summit on Bidwell’s road, Butte County. 
Andose. Richin small phenocrysts of plagioclase and pyroxene, mostly hypersthene, 
in agroundmass of the same minerals, with magnetite, and probably some amorphous 
matter. Analysis by W. F. Hillebrand, record No. 410. P. R. C. 1440. 
Q. Hypersthene andesite, old crater at head of Mill Creek. Andose. Contains 
small phenocrysts of plagioclase and hypersthene, in a groundmass of plagioclase, 
pyroxene, magnetite, etc. Some greenish pseudomorphs suggest former olivine. 
Analysis by T. M. Chatard, record No. 409. P. R. C. 1441. 
R. Hypersthene andesite, 2 miles south of Suppans Mountain, Tehama County. 
Tonalose. Abundant plagioclase and hypersthene, with traces of hornblende, in a 
microlitic groundmass. Analysis by Hillebrand, No. 672. P. R. C. 1442. 
S. Secretion in R. Bandose. Composed chiefly of plagioclase and hypersthene, 
with some quartz and amorphous matter. Analysis by Hillebrand, No. 673. 
P. R. C. 1443. 
T. Hypersthene andesite, west base of Suppans Mountain, near Lassen Peak, Tehama 
County. Tonalose: Contains numerous microscopic crystals of plagioclase and 
hypersthene, in a microlitic groundmass. Analysis by Hillebrand, No. 676. 
P. RB. C. 1444. 
Rocks dried at 100° to 110° before analysis. 
P Q R. s T 
55.20 | 57.11} 63.47 | 57.04 58. 08 
18.68 | 17.78 | 16.75) 19.11 18. 37 
3.14 3.54 2.15 4. 37 2.92 
4.42.) 2.74 2.75 2. 48 3. 38 
4.59 3. 41 3.04 3.94 3.35 
8. 02 7.21 5.72 7.34 7.05 
3. 66 3.81 3.94 3. 48 3. 66 
1.01 1.86 1. 62 1.16 1.33 
-d1 - 98 -55 1.09 1.09 
-92 95 37 47 ~44 
124 . 26 -13 08 -16 
14 - 33 09 12 13 
02 | trace? 04 02 02 
03 03 04! trace? 03 
none |........ trace | trace trace 
100. 58 | 100.01 | 100. 66 | 100. 7 100. 01 
