IGNEOUS AND CRYSTALLINE ROCKS. 57 
SOUTH DAKOTA. 
A. Phonolite, Black Hills. Miaskose. Described by Whitman Cross in Bull. 150, 
p. 191. Contains sanidine, nephelite, xgirite, nosean, and sodalite, with accessory 
sphene, apatite, and zircon, and possibly some rare zirconates or titanates. Also, 
sparingly, secondary zeolites and calcite. No magnetite, but minute ferritic flakes 
are disseminated through the rock. Analysis by W. F. Hillebrand, record No. 1618. 
P.R. C. 73. 
B. An earlier analysis of A, by H. N. Stokes, record No. 1314. This was made along 
the ordinary lines as regards ‘‘completeness,’’ as requested by the collector, and with- 
out regard to minor accessory constituents. It serves well to illustrate the difference 
between the two modes of treatment, in comparison with the fuller analysis. 
C. Tourmaline-biotite schist, north of Harney Peak, Black Hills. Described by 
Bayley in Bull. 150, p. 327. Contains quartz, biotite, tourmaline, a little garnet and 
rarely muscovite, iron ore, and apatite. Analysis by Stokes, record No. 1296. P. 
R. C. 130. 
D. Volcanic ash, 3 miles west of Argyle, Custer County. Amiatose. Collected by 
N.H. Darton. Analysis by George Steiger, record No. 1875. P. R. ©. 599. 
WYOMING. 
Rocks A to J, inclusive, studied by Whitman Cross. The Leucite Hills series is 
described in Am. Jour. Sci., 4th ser., vol. 4, p. 115. Analysis J is by L. G. Eakins, 
record No. 1078. The others are by W. F. Hillebrand, one made in the Denver 
laboratory, and record Nos. 343, 355, 362, 368, 403, 463, 1668, and 1682. 
A. Wyomingite, Boars Tusk, Leucite Hills. Wyomingose. Contains phlogopite, 
leucite, diopside, and apatite. Sp. gr., 2.779, 13.5°. P. R. ©. 566. 
B. Wyomingite. Fifteenmile Spring, Leucite Hills. Orendose. Composition like 
A. Sp. er., 2.627, 30° P. R. C. 567. 
C. Portion of B soluble in 2.5 per cent nitric acid. 
D. Phlogopite from wyomingite. 
E. Madupite, Pilot Butte, Leucite Hills. Madupose. Contains predominating 
diopside and phlogopite, with perofskite and magnetite, in a glassy base which has 
approximately the composition of leucite. Sp. gr., 2.857, 22°. P. R. ©. 576. 
