142 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
U. Hypersthene andesite, 1 mile southwest of Thumb, head of Bailey Creek, near 
Lassen Peak. Tonalose. Abundant but inconspicuous plagioclase and hypersthene, 
in a microlitic groundmass containing many small crystals of plagioclase. Analysis 
by W. F. Hillebrand, record No. 675. BP. R. C. 1445. 
V. Hypersthene andesite, west summit of Crater Peak, Shasta County. Yellow- 
stonose. Microphenocrysts of feldspar and hypersthene in a groundmass consisting 
largely of the same minerals, with some amorphous matter. Analysis by Hille- 
brand, No. 679. P. R. C. 1446. ; 
W. Hypersthene andesite, north slope of Crater Peak. Tonalose. Phenocrysts of 
plagioclase and hypersthene in a groundmass containing much dark amorphous 
matter. Analysis by Hillebrand, No. 680. P. R. C. 1447. 
X. Secretion in W. Hessose. Composed chiefly of plagioclase, hypersthene, and 
a globulitic base. Analysis by Hillebrand, No. 681. P. R. C. 1448. 
Y. Andesitic tuff, Stillwater Creek, 8 miles northeast of Redding. Contains pla- 
gioclase, hornblende, rare hypersthene, magnetite, and glass. Fragments of andesite 
are inclosed. Analysis by W. H. Melville, record No. 1346. Described by Diller 
in Bull. 150, p. 211. P. R.C. 79. 
Rocks dried at 100° to 110° before analysis. 
100. 07 | 100. 28 | 100.00 | 100.09 | 100. 23 
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. Con- 
tains plagioclase, pyroxene (mostly hypersthene), olivine, quartz, and much unindi- 
vidualized base; the latter about 25 percent. Magnetite is also present; augite occurs 
sparingly. Analysis by W. F. Hillebrand, record No. 407. P. R. G. 101. Also 
described in Bull. 150, p. 252. 
B. Volcanic bomb from quartz basalt, Cinder Cone. Andose. Analysis by Hille- 
brand, No. 665. P. R. C. 1449. ‘ 
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 pumiceous inclosure from quartz basalt, Cinder Cone. Alsbachose. 
Analysis by Hillebrand, No. 664. Mainly glass. P. R. GC. 793. 
Rocks dried at 100° to 110° before analysis. 
