GO 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
A. 
B. 
C. 
D. 
Si0 2 
69.94 
15.19 
1.88 
.60 
.92 
1.15 
3.95 
4.29 
.14 
.85 
.25 
.13 
trace 
.03 
72.35 
13.78 
1.87 
.36 
.42 
.87 
4.44 
4.49 
.22 
.54 
.44 
.13 
.20 
.06 
71.33 
12. 55 
3.75 
.85 
.58 
.94 
4,52 
4.20 
.12 
.30 
.55 
.16 
.15 
.04 
71.88 
12.88 
3.05 
1.05 
.33 
1.13 
4.21 
4.46 
.17 
.26 
.22 
.15 
.02 
trace 
A1 2 3 
FeoOo 
FeO 
MeO 
CaO 
Na 2 
K 2 
H 2 at 100° 
H 2 above 100° 
Ti0 2 
P 9 (X 
NiO 
MnO - 
99.32 
99.87 
100. 04 
99.81 
ARKANSAS. 
Ouachitite, dike near Maple Spring, 4 miles southwest of Hot 
Springs. Described by Kemp, in Ann. Rep. Geol. Survey Arkansas, 
1890, vol. 2, p. 399. A dike rock of the monchiquite group. Contains 
abundant and conspicuous augite and biotite, magnetite, and minor 
accessory minerals in a groundmass considered by Kemp as glass. 
Calcite and other secondary products are also present. According to 
Pirsson, Journ. Geol., vol. 4, p. 679, the so-called "glass" in the mon- 
chiquites is really analcite. Analysis by L. G. Eakins, record No. 1023. 
Si0 2 ., 
A1 2 3 . 
Fe 2 3 
FeO.. 
MgO. 
CaO.. 
Na 2 0. 
36.40 
12.94 
8.27 
4.59 
11.44 
14.46 
.97 
K 2 
H 2 
Ti0 2 
PA 
co 2 
3.01 
2.36 
.42 
1.04 
3.94 
99.84 
TEXAS. 
A. Quartz-pantellarite, Vieja Mountains, San Carlos, Presidio 
County. Description furnished by E. C. E. Lord. Contains anortho- 
clase, augite, and grains of quartz in a groundmass of aegirine augite, 
a brown hornblende, which is probably barkevikite, orthoclase, and 
quartz. Magnetite and apatite are present as accessory minerals. 
Analysis by George Steiger, record No. 1581. 
