CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
165 
F. Tinguaite?, Two Buttes. Collected by (>. K. Gilbert; petro- 
graphic data supplied by Whitman Cross. Consists chiefly of pale- 
green augite, hornblende, apatite, magnetite, and occasional crystals 
of alkali feldspar, in an obscure, largety isotropic groundmass. Sp. gr. , 
2.79, 25°. 
G. Pyroxene from F. Sp. gr., 3.43, 28°. 
H. Portion of F soluble in ^ nitric acid. 
I. Syenitic lamprophyre?, Two Buttes. Collected by Gilbert; 
description by Cross. Chief constituents, diopside, alkali feldspar, 
considerable biotite, magnetite, and olivine. The ferromagnesian 
minerals predominate. Sp. gr., 2.88, 29°. Also contains 0.03 V 2 3 . 
J. Pyroxene from I. Sp. gr., 3.45, 25°. 
K. Portion of I soluble in T V nitric acid. 
Analyses F to K by W. F. Hillebrand, record No. 1604. 
F. 
G. 
H. 
I. 
J. 
K. 
Si0 2 .. 
47.61 
14.26 
4.90 
4.07 
2.62 
8.71 
6.70 
4.08 
.26 
1.89 
1.38 
1.38 
.18 
trace? 
trace 
.30 
.36 
.41 
trace 
1.17 
.03 
.37 
trace 
47.54 
4.14 
5.64 
6.42 
10.05 
21.57 
1.38 
.12 
none 
undet. 
3.00 
13. 27 
9.40 
trace 
trace 
1.70 
5.41 
.66 
undet. 
undet. 
50. 41 
12.30 
5.71 
3.06 
8.69 
7.08 
.97 
7.53 
.46 
1.80 
1.47 
.46 
none 
trace 
.04 
.15 
.06 
.23 
trace 
none 
none 
trace 
trace? 
51. 27 
3.05 
3.08 
4.34 
14.21 
22. 58 
.67 
.06 
none 
undet. 
.70 
1.58 
1.00 
none 
.87 
1.22 
.68 
undet. 
undet. 
none 
undet. 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 OatllO°... 
H 2 above 110° 
Ti0 2 
P 2 5 
1.34 
.46 
Zr0 2 
none 
trace? 
trace 
.36 
none 
none 
trace 
none 
none 
.03 
.28 
none 
none 
Cr 2 3 
NiO 
MnO . 
trace 
.11 
none 
(?) 
.77 
.03 
.37 
trace 
trace 
(?) 
none 
SrO 
BaO 
Li 2 
so 2 
S 
CI 
trace 
F 
100. 68 
100. 21 
33.06 
100. 42 
100. 27 
5.81 
