IGNEOUS AND CRYSTALLINE ROCKS. 151 
D. Altered wall rock, Mina Rica vein. Sp. gr., 2.979, 20°. 
E. Altered wall rock, Plantz vein. These rocks, D and E, contain quartz, musco- 
vite, a little chlorite, pyrite, and sphene, with carbonates of calcium, magnesium, 
and iron. 
A B c. D E 
60.09 | 37.01 46.13 
16.43 | 12.99 15. 82 
2.28 +43 -89 
3.01 3. 57 2.27 
4.37 5. 49 2,13 
5.76 9.78 10. 68 
4. 52 «13 -17 
-70 4.02 5.30 
20 -13 12 
1.16 1.92 2. 42 
-85 67 
12 - 06 10 
12 24 09 
99.80 | 99.69 99. 68 
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. 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. 66. 
B. Granodiorite, Donner Pass. Tonalose. Contains plagioclase, orthoclase, quartz, 
hornblende, biotite, and sphene. P. R. C. 1525. 
* C. Gabbro, 2 miles south of Emigrant Gap, on road to Onion Valley. Andose. 
Contains biotite, hypersthene, diallage, plagioclase, and orthoclase. P. R. C. 1523. 
D. Gabbro, same locality as C. Vaalose. Contains hypersthene, diallage, plagio- 
clase, and orthoclase. P. R. C. 1524. 
E. Quartz diorite, southeast spur of English Mountain. /Placerose. Contains 
“basic” plagioclase, augite, and quartz. P. R. C. 1522. 
