LARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
61 
The following rocks from Uvalde County were collected by T. Way- 
ind Vaughan. Petrographic data furnished by Whitman Cross. 
Analyses by W. F. Hillebrand, record No. 1681. 
B. Plagioclase-basalt, Pinto Mountain, Brackett quadrangle. Con- 
ains olivine, augite, plagioclase (labradorite), biotite, a very little 
lkali feldspar (?), magnetite, and apatite. Sp. gr. 3.118, 20°. P. R. 
}. 1067. 
C. Basanite, Mount Inge, Uvalde quadrangle. Contains sanidine,, 
ephelite, hornblende, augite, segirine augite, olivine, magnetite, apa- 
ite, and a trace of pyrite. Sp. gr. 2.770, 20°. P. R. (5 1069. 
D. Pock of basaltic habit, allied to C, 1 mile northeast of Big 
fountain, Uvalde quadrangle. Contains alkali feldspar, augite, mag- 
etite, and variable amounts of olivine, nephelite, aegirite, biotite, and 
eolitic minerals. Sp. gr. 2.742, 23°. P. R. C. 1068. 
A. 
B. 
c. 
L>. 
Si0 2 
68.71 
13.45 
5.31 
.75 
.19 
.96 
4.63 
5.51 
.13 
.36 
.21 
.04 
45.11 
a 12. 44 
2.67 
9.36 
11.56 
10.61 
3.05 
1.01 
.16 
.78 
2.34 
.51 
(?) 
48.13 
18.44 
3.41 
4.30 
3.06 
5.89 
8.00 
3.80 
.18 
1.59 
1.74 
.49 
.05 
none 
48.23 
17.43 
2.77 
5.92 
2.99 
6.38 
6.87 
2.78 
.54 
2.84 
2.00 
.69 
.04 
none 
.04 
trace 
.18 
.08 
.08 
trace 
.08 
AL0 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatll0° 
H 2 above 110° 
Ti0 2 
P 9 0, 
Zr0 2 
Cr 2 3 
v 2 o, 
.04 
.04 
.22 
trace 
trace 
none 
.01 
NiO 
.02 
.19 
.10 
.10 
trace 
.09 
MnO 
.14 
none 
none 
none 
SrO 
BaO 
Li 2 
S 
S0 3 
.05 
CI 
.11 
undet. 
.29 
.06 
.03 
undet. 
F 
Less O , 
100.44 
100.02 
.02 
99.93 
.09 
99.97 
100.00 
99.84 
a Including Cr 2 3 . 
