236 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
7. TRAVIS COUNTY, TEXAS. 
Analyzed by L. G. Eakins, record No. 1097, and described in Bull. 
78, p. 91. Sp. gr. 3.513, 20°. According to Cross, the stony portion 
contains olivine and enstatite, with a small amount of a colorless min- 
eral, which is probably feldspar. Chromite is also present. 
Approximate composition of the ?nass. 
Nickel-iron 2. 23 
Troilite 5. 03 
Soluble silicates 39. 84 
Insoluble silicates 52. 42 
99.52 
A. Total analysis. 
B. Nickel-iron. 
C. Silicates soluble in hydrochloric acid, calculated to 100 per cent. 
D. Insoluble silicates, calculated to 100 per cent. 
A. 
B. 
c. 
D. 
Si0 2 
A1 2 3 
44.75 
2.72 
.52 
trace 
16.04 
1.83 
.52 
.22 
.01 
trace 
2.23 
27. 93 
.13 
1.13 
.41 
1.83 
.84 
38.13 
2.58 
56. 14 
3.73 
1.00 
Cr 2 3 
CuO 
FeO ... 
19. 76 
9.15 
Fe . 
88.74 
NiO 
1.19 
Ni 
10.68 
.58 
Co 
MnO . . 
GaO. 
1.02 
37.32 
undet. 
undet. 
3.59 
24.44 
.19 
1.76 
MgO 
K. 2 
Na 2 . . 
P 9 (X 
s 
H,0 
Less O = S 
101. 11 
.92 
100. 00 
100. 00 
100. 00 
100. 19 
