198 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
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. Hillebrand, 
record No. 1419. 
A. Granite, Rocklin. A normal granite, containing quartz, ortho- 
clase, 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. W, 
B. Granodiorite, Donner Pass. Contains plagioclase, orthoclase, 
quartz, hornblende, biotite, and sphene. 
C. Gabbro, 2 miles south of Emigrant Gap, on road to Onion Val- 
ley. Contains biotite, hypersthene, diallage, plagioclase, and ortho- 
clase. 
D. Gabbro, same locality as C. Contains hypersthene, diallage, 
plagioclase, and orthoclase. 
E. Augite-granite, southeast spur of English Mountain. Contains 
" basic" plagioclase, augite, and quartz. 
A. 
B. 
c. 
D. 
E. 
Si0 2 
73.00 
16.38 
none 
.99 
.48 
2.42 
4.53 
1.87 
| .52 
59.48 
17. 25 
2.15 
4.06 
2.67 
6.50 
3.53 
2.27 
.09 
.71 
.93 
.33 
.11 
trace 
.09 
trace 
55.40 
15. 32 
2.70 
5.49 
5. 75 
9.90 
2.89 
1.52 
.03 
.38 
.60 
.22 
.11 
none 
.07 
trace 
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 
64.67 
16.62 
.51 
.76 
2.26 
9.50 
4.10 
.34 
.08 
.37 
.51 
.12 
trace 
trace 
.02 
trace 
ALO, 
Fe 2 0, 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl00° 
H 2 above 100° 
Ti0 2 
P 2 5 
MnO 
SrO... 
BaO 
Li 2 
100. 19 
100. 17 
100. 38 
100. 08 
99.86 
