IGNEOUS AND CRYSTALLINE ROCKS. 131 
Ik. Dacite, near summit of Diamond Peak. Harzose near tonalose. Contains pla- 
gioclase, hornblende, augite, biotite, quartz, apatite, magnetite, and glass. 
G. Altered dacite, Combination mine. Contains quartz, kaolin, sericite, pyrite 
and possibly alunite. 
H. Biotite dacite vitrophyre, 1 mile southwest of Black Cap Mountain. Amiatose. 
Contains labradorite, biotite, and quartz in a glassy base. 
I. Dacite, one-half mile northeast from summit of Columbia Mountain. Tonalose. 
Contains the same minerals as F. 
J. Mica dolerite, 2 miles east of Black Butte. Hessose. Contains anorthite, augite, 
biotite, olivine, magnetite, occasional hornblende, scanty apatite, and a little calcite. 
The olivine is serpentinized. 
K. Olivine dolerite, mesa above Rabbit Spring. Hessose. Contains anorthite and 
olivine in a groundmass of plagioclase, augite, olivine, magnetite, andapatite. Avery 
little hornblende is also present, with a trace of calcite. The olivine isserpentinized. 
Ee G. H I J. kK 
OF cece kt ledateiae din Bosom cerca aesisten SSS sfeiereie 59.99 | 59.95 | 48.59 48.20 
AlDOS yi sace twats Seeisioeiwea neceeiimawentens 16.14] 15.77) 17.80 21. 47 
POO 3 ecciccaiicnen ani nese sveamnwrnae ssa 4.42 3.34 8.70 5.89 
BG O's os srsicines cps crorsanstarnaions inaraamnisiagcte aa 13 2.34 93 2.20 
ME Ole crarzsicisis tiatemrnunciotd tsisiawictoere sw a 1.51 2.73 4,85 3. 33 
CAO seca oumich wtvny een acnemnieaimenessin 4.17 5.84 | 10.49 10. 60 
Na2O ievoccecive oveinceauate siemeeese sess 3. 04 3. 07 3. 06 3.10 
BESO oc aseiataiels cesbicl igang sci AEROS ORE 2.82 2. 52 1.70 1.33 
TOG 00 aig 2.5 ssc ciara nce siaisinnrateinwrnbets 3.35 95 -76 96 
H20 above 105° 4. 06 2.00 67 1.20 
