CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
237 
orthocla.se and augite, with less plagioclase and quartz. Analysis by 
Stokes, No. 1642. P. R. C. 789. 
C. Diorite, dike 1^ miles southeasterly from Sonora. Tonalose. 
Contains feldspar largely altered to hornblende. A few black grains 
are probably iron ore. Analysis by W. F. Hillebrand, record No. 
1548. P. n. C. 759. 
D. Quartz-pyroxene-diorite, large area east of Sonora. Harzose. 
Contains plagioclase, quartz, biotite, augite, rhombic pyroxene, and 
a trace of iron ore. Analysis by Hillebrand, No. 1548. P. R. C. 760. 
E. Diorite, dike about 1^ miles southeasterly from Sonora. Canvp- 
tonose. Contains altered plagioclase and hornblende, with epidote, 
chlorite, and iron disulphide as secondary products. Analysis by 
Hillebrand, No. 1548. P. R. C. 761. 
A. 
B. 
c. 
D. 
E. 
SiO., 
67.53 
18. 57 
1.13 
.08 
.24 
.55 
11.50 
.10 
.15 
.31 
.07 
.11 
trace 
61.28 
14.71 
1.21 
2.85 
1.69 
5.61 
2.99 
7.70 
.28 
.43 
.41 
.16 
trace 
58. 05 
15. 46 
1.69 
5.09 
4.84 
6.94 
2.86 
2.14 
.10 
2.02 
.72 
.16 
.14 
none 
trace 
.07 
trace 
57. 80 
16. 43 
1.62 
6.51 
4.14 
7.21 
2.35 
2.29 
.11 
.38 
.70 
.19 
.18 
.03 
trace? 
.09 
trace 
53. 46 
ALO, 
14.81 
Fe,0, 
2.60 
FeO 
5.15 
MgO 
7.27 
CaO. 
8.44 
Na 2 G 
2.64 
K 2 
1.30 
H 2 at 110° 
.12 
H 2 above 110° 
2. 13 
Ti0 2 
.70 
P 2 5 
.16 
MnO. 
NiO 
.18 
.05 
SrO . 
trace 
.04 
.72 
trace 
BaO 
.05 
Li 2 
trace 
so 3 
trace 
.08 
CO, 
none 
none 
.44 
F 
trace 
FeS 2 
none 
none 
.26 
100. 34 
100. 16 
100. 28 
100. 03 
99.76 
