294 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
The following bedded sandstones of the same region are also 
described: 
F. From middle fork of Cottonwood, 1 mile above Miller's. 
G. Top of cascade, H miles up Byron Creek from north fork of 
Cottonwood. 
H. Two and one-half miles above John Allen's, Dry Creek. 
Analyses F and Or by Chatard, record No. 1106; H by Whitfield, 
record No. 971. 
Si0 2 
A1A 
Fe 2 3 
FeO 
MgO ...... 
CaO 
Na 2 
K 2 
H,0 at 100 c 
Ti0 2 
PA- 
MnO 
BaO. 
C0 2 . 
S0 3 . 
01... 
F. 
55.85 
13.20 
2.56 
4.77 
1.90 
6.93 
2.60 
1.89 
1.13 
2.99 
.76 
.18 
.24 
undet. 
4.97 
99.97 
67.62 
13.63 
1.25 
3.27 
2.34 
2.80 
2.78 
1.11 
.64 
2.83 
.48 
.08 
.15 
.03 
.72 
99.73 
H. 
60.74 
10. 25 
4.31 
6.21 
3.69 
4.97 
1.83 
.52 
4.36 
.86 
trace 
trace 
2.29 
.40 
trace 
100.43 
3. SANDSTONE FROM SULPHUR BANK. 
Described by Becker in Mon. XIII, p. 92. Analysis made by 
Melville in the San Francisco laboratory. An altered sandstone, 
showing grains of quartz, plagiociase, and orthoclase. 
Si0 2 68. 50 
Al A 12. 82 
Fe 2 3 
FeO. 
MgO. 
CaO. 
Na 2 
1.29 
3.37 
2.21 
1.82 
6.03 
1.26 
28 
H 2 above 100° 2. 11 
Ti0 2 60 
P 2 5 - 16 
MnO .02 
100. 47 
