CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
231 
Second, rocks from other localities in Placer County. Studied also 
by Lindgren, who furnishes the petrographic data. Analysis A by 
W. H. Melville, record No. 1346; B, C, D, and E by W. F. Hille- 
brand, record No. 1119. 
A. Granite, Rocklin. Lassenose. A normal granite, containing 
quartz, orthoclase, plagioclase, biotite, muscovite, magnetite, apatite, 
and zircon, with some secondary chlorite and epidote derived from 
the biotite, Described by Lindgren in Bull. 150, p. 170. P. R. C. m. 
B. Granodiorite, Donner Pass. Ton/dose. Contains plagioclase, 
orthoclase, quartz, hornblende, biotite, and sphene. 
C. Gabbro, 2 miles south of Emigrant Gap, on road to Onion Val- 
ley. Andose. Contains biotite, hypersthene, diallage, plagioclase, 
and orthoclase. 
D. Gabbro, same locality as C. Vaalose. Contains hypersthene, 
diallage, plagioclase, and orthoclase. 
E. Augite-granite, southeast spur of English Mountain. Placerose. 
Contains u basic" plagioclase, augite, and quartz. 
Si0 2 . 
A1A 
Fe 2 3 
FeO. 
MgO 
CaO. 
Na 2 
K 2 0. 
H 2 above 100 c 
Ti0 2 
MnO 
SrO. 
BaO. 
73.00 
16.38 
none 
.99 
.48 
2.42 
4.53 
1.87 
.52 
100. 19 
B. 
59.48 
17.25 
2.15 
4.06 
2.67 
6.50 
3.53 
2.27 
.09 
.71 
.93 
.33 
.11 
trace 
.09 
trace 
100. 17 
c. 
55.40 
15. 32 
2.70 
5.49 
5. 75 
9.90 
2.89 
1.52 
.03 
.38 
.60 
.22 
.11 
none 
.07 
trace 
100. 38 
D. 
55. 87 
13.52 
2.70 
5.89 
6.51 
8.87 
2.42 
1.72 
.09 
1.56 
.56 
.25 
.10 
none 
.02 
trace 
100. 08 
64.67 
16.62 
.51 
.76 
2.26 
9.50 
4.10 
.34 
.08 
.37 
.51 
.12 
trace 
trace 
.02 
trace 
99.86 
