IGNEOUS AND CRYSTALLINE ROCKS. 1638 
41 44 22 
K2O.... i 5 trace |........ 16 
H20 at 100°. ..... Lunveinleierieiia weunlcalhen meno NgamUelIgs sanmdislGameNt : -44 3.32 . 39 
He BDOVE! 100? o 5 cueveractascnenadt a aesaasags ssheeweeinaes aereeerar 15.72 | 12.40} 12.51 20. 43 
BOs: vsasascagigians arueeaens at a4 Aoeeeeen es eeamemey 
GEO sh ca ctin dine ciachaasaig bioresaiecinemia ae ae ce tees MER 
NiO. 
MnO ssc cateiaisaie FeSirtieniieigh an aed keieayseS abies 
BOgscraasecces 
99.56 | 100.70 | 101.06 | 100.15 
15. MISCELLANEOUS ROCKS. 
A. Rhyolitic obsidian, Medicine Lake, Modoc County. Toscanose. Collected by 
J. 8. Diller, who reports it to be a banded obsidian, containing a few minute feldspar 
crystals. The banding is due to a multitude of trichites. Analysis by L. G. Eakins, 
record No. 1072. 
B. Rhyolite, Hyampom, south fork of Trinity River, Trinity County. Tehamose. 
Almost wholly made up of particles of clear glass. Collected and described by Diller. 
Analysis by George Steiger, record No. 1427. P. R. C. 1455. 
C. Tuff from Redding Creek basin, Trinity County. Collected by J. 8. Diller. 
Analysis by E. T. Allen, record No. 2020. 
D. Diabase porphyrite, one-half mile west of Browns Valley, Yuba County. 
Auvergnose. Collected and described by W. Lindgren. Contains augite, plagioclase, 
magnetite, chlorite, and epidote. Analysis by W. F. Hillebrand, record No. 1419. 
E. Amphibolitic schist, 1 mile northeast of Browns Valley, Yuba County. Col- 
lected and described by W. Lindgren. From metamorphosis of C. Contains chiefly 
green hornblende and feldspar. Analysis by Hillebrand, No. 1419. 
Ko 
H,0 at 100°........ 
H20 above 100° 
F. Basalt, base of a lava flow, east of the head of the San Joaquin River, Madera 
County. Andose. Description supplied by Turner. Hitherto unpublished. Con- 
tains pyroxene, partly augite, plagioclase, olivine, and iron ores, Analysis by W. F, 
Hillebrand, record No, 1767, 
