72 
ANALYSES OF ROCKS, 17. S. GEOLOGICAL SURVEY. 
[NO. 228. 
E. Phonolite, hill between Black and Big mountains, Uvalde quad- 
rangle. Laurdalose. Contains sanidine, nephelite, and segirite, and 
very little brown hornblende, augite, and magnetite. Sp. gr., 2.559, 
19.5 \ P. R. C. 1070. 
F. The portion of E soluble in 1:40 dilute nitric acid. 
G. Nepheline-basalt, Tom Munns Hill, Uvalde quadrangle. Uvald- 
ose. Contains olivine, augite, nephelite, magnetite, and apatite. Sp. 
gr., 3.118, 19°. P. R. C. 1065. 
H. The portion of G soluble in 1:10 dilute nitric acid. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 OatllO°... 
H 2 above 110 c 
Ti0 2 
PA 
ZrO, 
CrA 
NiO 
MnO 
SrO 
BaO 
Li 2 Q 
S 
so 3 
CI 
F 
Less O 
E. 
54. 42 
20.76 
2. 64 
1.33 
.22 
1.34 
10. 41 
4.89 
.22 
2. 50 
.40 
.11 
.15 
none 
none 
.15 
trace 
.04 
trace 
.01 
.23 
none 
99.82 
.05 
99.77 
26. 90 
14. 34 
. 60 
(?) 
.30 
8. 32 
1 . 22 
(?) 
(?) 
1 ! 
51. 79 
G. 
40.32 
«9.46 
4.75 
7.48 
18.12 
10. 55 
2.62 
1.10 
.57 
1.25 
2.66 
.68 
none 
.06 
.25 
.03 
.06 
trace 
.01 
.03 
.05 
.04 
100. 09 
.03 
100. 06 
H, 
12. 27 
6.09 
2.83 
6.48 
1.45 
2.39 
.93 
(?) 
(?) 
68 
33.12 
« Including Cr 2 3 
