IGNEOUS AND CRYSTALLINE ROCKS. 171 
J. Basalt, Sawtooth Rock. I. 5.3.5. Largely feldspar and pyroxene, with some 
quartz. 
K. Dacite porphyry, 6 miles west of Big Bend of Rogue River. Kallerudose. 
Contains plagioclase and quartz, with some orthoclase, and scattered patches of chlorite 
and hornblende. 
L. Dacite porphyry, head of Boulder Creek. Yellowstonose. Contains abundant 
quartz, altered feldspar, grains of epidote, hornblende, and chlorite. 
M. Dacite porphyry, south slope of Bald Mountain. Alsbachose-lassenose. 
J K L. M 
SiO swe scsneensmtwccinsa memantine oe eeuiseileeuieneis an ectiniomsing £6 sisisinaciede 53.06 | 71.45 | 70.33 75. 32 
AlzO3-. . 12.83 | 14.53 | 15.74 13.17 
Fe203 1.20 49 1. 43 27 
FeO. 5.10 +94 83 98 
MgO. 7.50 30 53 42 
CaO 13.71 2.01 3.38 1. 48 
IN Rasa sca slhss.chcsesatasaiate nce heseacartaaria basi tat aeaag decry le Ne Rl seteaieashesoeo ale Sw Sosleusee 3. 56 7.15 4, 33 4.77 
SSO! oa araassdehcicanrslaeeceesstet a ey tyaieidege ssa eed eA as care SoA Oo eae -05 2.55 1.87 2.14 
PROTA G OS. roca ote Fale dior ee widvrenes Cooddeau hl La Se Sete eee seea aoe 16 15 20 18 
H20 above 105° i 
TiOs. 
COs... 
ZrOz. 
P205. 
Sisco vines SSeS eeeeea yee eEeReeese 
FeSo. MEVSAA sch ERPaRIGNSS 3 Eee SEE 
MnO) os cis ese asceaincteneoeates 
BAO e cnisciPassimcaraceanissigadaces 
sro. 
Cr203 
100. 22 | 100.31 | 100.22 | 100.03 
5. MISCELLANEOUS ROCKS. 
A. Normal granodiorite from near lake at base of Bald Mountain, northwest of 
Sumpter. Yellowstonose. Described by Lindgren in 22d Ann., Part II, p. 587. 
Contains quartz, hornblende, andesine, orthoclase, biotite, and magnetite. Slight 
alterations to epidote and chlorite are sometimes noticeable. Analysis by W. F. 
Hillebrand, record No. 1896. P.R. C. 1529. 
B. Rock from Wilbur, Douglas County. A tuff partly of igneous, partly of organic, 
origin. The igneous matter contains a few grains of feldspar and augite, with particles 
of a rock like diabase. The organic remains are partly calcareous and partly siliceous. 
Description supplied by J. 8. Diller. Analysis by H. N. Stokes, record No. 1737. 
C. Basaltic tuff, Columbia River, 25 miles east of Portland. Described by Diller 
in Bull. 260, p. 3438. Analysis by G. Steiger, record No. 2165. 
K20.-.....- 
20 at 105°... 
H20 above 105° 
TiO. 
100.05 | 99.79 | 100.60 
a Includes TiOg and P20s, if present. 
