260 
ANALYSES OF BOCKS, U. S. GEOLOGICAL SURVEY. 
[NO. 228. 
1. PORT ORFORD QUADRANGLE. 
Rocks collected by J. S. Diller, and partially described by him in 
Folio 89. Analysis A by George Steiger, record No. 1892. B, I), E, 
F, by H. N. Stokes, record No. 1891. C, G, H, I, J, K, L, M, by 
W. F. Hillebrand, record No. 1897. 
A. Serpentine, from 12 miles north of mouth of Boulder Creek. 
B. Serpentine, from Iron Mountain crest. Contains, with serpen- 
tine, olivine, pyroxene, sometimes hornblende, and magnetite, with 
picotite or chromite. 
C. Metagabbro, southeast slope of Panther Mountain. Hessose. 
Much altered. Contains plagioclase, and pale-green fibrous horn- 
blende. Fine scales of mica and groups of epidote are also common. 
D. Normal metagabbro, summit of Bald Mountain. Aiwergnose. 
Contains plagioclase, hornblende, numerous grains of magnetite or 
ilmenite, and traces apparently of pyroxene. 
A. 
B. 
c. 
D. 
SiO, 
39.42 
1.39 
3.42 
4.29 
39.68 
1.10 
none 
none 
.36 
9.53 
none 
38.55 
1.32 
5.55 
2.17 
39. 06 
.85 
.10 
.05 
1.14 
10. 14 
trace 
44.19 
20.66 
.52 
3.26 
11.90 
10. 76 
1.35 
1.03 
.74 
5. 19 
.12 
none 
.06 
trace 
trace 
.15 
.03 
.11 
.04 
.05 
(?) 
50.14 
A1 2 3 
15.26 
Fe.Oo 
1.19 
Fe() 
8.75 
MgO 
7.21 
CaO 
9.34 
Na 2 
2.76 
K 2 
H 2 at 105° 
.'95 
.23 
H,0 above 105° 
2.22 
TiO, 
1.42 
Zr0 2 
CO, 
.51 
trace 
.03 
.48 
.13 
.05 
none 
none 
trace 
none 
P.,0 
none 
.24 
s 
.04 
o,o, 
.58 
trace 
MO 
MnO 
trace 
none 
trace 
BaO 
.03 
SrO 
none 
LU) 
none 
99.77 
100.13 
100. 16 
99.78 
