IGNEOUS AND CRYSTALLINE ROOKS. 
261 
E. Gabbro, Brush Creek, 1| miles southwest of Bald Mountain. 
Tellowstonose. Rich in quartz and feldspar, with subordinate biotite 
and hornblende. Contains some chlorite. 
F. Gabbro, west of Brush Creek, near summit of Mussel Creek 
divide. SB. 5 ofkilauase. Chiefly feldspar and pyroxene, the latter 
partly changed to hornblende. A little quartz is present. 
G. Gabbro, left bank of Rogue River, 2 miles below the mouth of 
Illinois River. SR. 5 of monzonase. Consists mainly of plagioclase 
and hornblende. 
H. Basalt, Cedar Creek, 1J miles northeast of Ophir. Auvergnose. 
Consists mainly of hornblende and feldspar. Grains of pyroxene are 
present, and a black dust which appears to be magnetite. 
I. Basalt, near fork of West Bend trail, 2£ miles south of Johnson 
Creek. Beevbaclwse. Contains plagioclase and pyroxene, with sec- 
ondarv chlorite and hornblende. 
Si0 2 .. 
A1A- 
Fe 2 3 
FeO.. 
MgO. 
CaO.. 
Na 2 0. 
K,0 . . 
H 2 above 105° 
Ti0 2 
ZrO, 
co 2 
NiO . 
S ... 
FeS 2 
MnO 
BaO. 
SrO. 
0.88 
7.71 
2. 92 
2.17 
2. 21 
4.32 
4.17 
2. 68 
.54 
1.47 
.41 
.16 
none 
none 
trace 
trace 
.06 
trace 
99.70 
F. 
56. 45 
13. 81 
1.73 
3. 95 
8.67 
6. 69 
5.03 
.46 
.67 
2.02 
.31 
.02 
none 
trace 
trace 
trace 
trace 
.02 
99.83 
57.43 
17.69 
1.59 
3.48 
2.73 
5. 72 
7.19 
.58 
.48 
1.81 
.66 
none 
.17 
.10 
.02 
.17 
none 
.02 
99.84 
50. 56 
14.49 
1.78 
10.20 
5.90 
10. 13 
2.91 
.38 
.20 
1.50 
1.67 
none 
trace 
(?) 
trace 
.28 
.25 
trace 
none 
100. 25 
I. 
52.12 
15. 21 
1.83 
8.95 
6.01 
3.75 
4.83 
.48 
.90 
3.74 
1.38 
none 
.14 
.09 
none 
.03 
trace 
.19 
trace 
none 
99.65 
