CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
145 
THIRD GROUP. MISCELLANEOUS ROCKS. 
Analyses, hitherto unpublished, except when otherwise stated, by 
W. F. Hillebrand, record Nos. 1-148, 1453, and 1669. Petrographic data 
supplied by Whitman Cross. Names marked with a query are provi- 
sional designations only. 
A. Trachyte?, near Robbing's ranch. Has scattered phenocrysts of 
alkali feldspar, oligoclase, and biotite in a predominant trachytic 
groundmass of alkali feldspar, tridymite, particles of residual glass, 
and ferritie flakes and grains. 
B. Trachyte?, Wicher Mountain. Shows biotite and a few glassy 
feldspars in a groundmass resembling that $f A. 
C. Andesite?, Bare Hills. Composed mainly of plagioclase and 
alkali feldspar, with small augites and much ferritie matter. Minute 
prisms of a yellowish brown amphibole (?) and scales of tridymite are 
also visible. 
D. Pyroxene-andesite?, Wicher Mountain. Contains phenocrysts of 
plagioclase, a few of augite, minute specks of iddingsite, and flakes 
of limonite. In the groundmass are plagioclase, orthoclase (?), augite, 
iddingsite, and hypersthene. In the pores tridymite appears. Con- 
tains 0.02 V 2 3 . 
E. Plagioclase-basalt?, mesa east of Mac Gulch. Contains plagio- 
clase, augite, olivine, iddingsite, magnetite, biotite, and apatite. 
F. Plagioclase-basalt, Saddle Mountain. Phenocrysts of augite and 
olivine in a groundmass of plagioclase, orthoclase, augite, magnetite, 
biotite, and apatite. Very fresh. See Cross, Journ. Geol., Vol. 5, 
p. 684. 
A. 
B. 
C 
D. 
E. 
F. 
Si0 2 
69.52 
15. 44 
1.90 
.09 
.17 
1.70 
4.54 
5.04 
.33 
.27 
.23 
.14 
.05 
.08 
.04 
.19 
66.12 
17.21 
2.43 
trace 
.35 
2.11 
4.70 
5.57 
.14 
.71 
.29 
.11 
.06 
.08 
.05 
.25 
62.64 
17.82 
3.91 
.31 
.47 
3.22 
4.47 
4.99 
.58 
.65 
.59 
.25 
.08 
.04 
.07 
.28 
57.48 
18.04 
5.73 
.73 
1.17 
5.03 
4.28 
4.15 
.62 
.55 
1.00 
.66 
.01 
trace 
.12 
.20 
.16 
52. 97 
18. 31 
L.86 
6.73 
3.04 
6.51 
3.74 
3. 35 
.44 
.31 
1.04 
.81 
.05 
.00 
. 14 
. is 
48. 76 
15.89 
6.04 
4. 56 
5.98 
8.15 
3. 43 
2.93 
.40 
1.48 
1.65 
.60 
none 
.13 
.06 
.17 
A1 2 3 .. 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl00°.._ 
H 2 above 100° 
Ti0 2 
P 2 5 
Zr0 2 
MnO 
SrO 
BaO 
SO, 
co 2 
.17 
99.90 
100. 18 
100. 37 
99.96 
99.57 
100. 23 
Bull. 168- 
-10 
