IGNEOUS AND CRYSTALLINE ROCKS. 41 
ARKANSAS. 
Ouachitite, dike near Maple Spring, 4 miles southwest of Hot Springs. SR. 2 of 
etindase. Described by Kemp, in Ann. Rept. 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 con- 
sidered by Kemp to be glass. Calcite and other secondary products are also present. 
According to Pirsson, Jour. Geology, vol. 4, p. 679, the so-called ‘‘glass” in the 
monchiquites is really analcite. Analysis by L. G. Eakins, record No. 1023. P.R.C. 
395. 
SLO Seip scisencecie aces gineied drasine tog mcmes BOUAO) If We Ocec baoradanwaselt an Caweonrmanvnadvedvrnserdaawowaae 3.01 
Yt Ok nenere A ari Rae eae CES nc a AQ SOAD Tl 9 Oe ceoetyere teaver rod pe lore en era iat 2.36 
GIO 9 25k Scstynsd sue ateteeataGcaRererniat Bol | TO gs eicc.eccecaerse sere eoemwennerse eee omceeT 42 
FG Oia. cseataeneGeaimbaterbareneeuernenseee B50. | DaOgissoscisncimieaiee s aineinistimemiiaviciosccn 1.04 
INE OF see es ase csercacas sie rs tcrtacnssmierate ta Sesion kede eae AA CO gs scissors peat he toaninaaicince an eens 3.94 
COO siisicrision cmeimstha nearer dentwensecins 14. 46 ——— 
N89 Obie ccsenciea eae voggtawaeaenosaceens tor 97 99. 84 
OKLAHOMA. 
Granite, west of Mount Sheridan, Wichita Mountains, collected by J. P. Iddings. 
Analysis by G. Steiger, record No. 2335. 
SiOz... 
AlaO3... 
ZrOz and COs absent. 
TEXAS. 
A. Quartz pantellerite, Vieja Mountains, San Carlos, Presidio County. Liparose. 
Description furnished by E. C. E. Lord, Contains anorthoclase, augite, and grains- 
of quartz in a groundmass of egirine-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. 
The following rocks, analyses B to. M, from Uvalde County were collected by T. 
Wayland Vaughan. Petrographic data furnished by Whitman Cross. Analyses by 
W. F. Hillebrand, record No. 1681. 
B. Plagioclase basalt, Pinto Mountain, Brackett quadrangle. Limburgose. Con- 
tains olivine, augite, plagioclase (labradorite), biotite, a very little alkali feldspar (?), 
magnetite, and apatite. Sp. gr., 3.118, 20° P. R. C. 1067. 
C. Basanite, Mount Inge, Uvalde quadrangle. Lujavrose. Contains sanidine, 
nephelite, hornblende, augite, wgirine-augite, olivine, magnetite, apatite, and a trace 
of pyrite. Sp. gr., 2.770, 20°. P. R. C. 1069. 
D. Rock of basaltic habit, allied to C, 1 mile northeast of Big Mountain, Uvalde 
quadrangle. Essexose. Contains alkali feldspar, augite, magnetite, and variable 
amounts of olivine, nephelite, zgirite, biotite, and zeolitic minerals. Sp. gr., 2.742, 
23°, P.R. C. 1068, 
