54 
ANALYSES OF EOCKS, U. S. GEOLOGICAL SUEVEY. 
[BULL. 168. 
The following rocks from Corundum Hill were collected, analyzed, 
and described by T. M. Chatard, Bull. 42, p. 45. 
I. Altered gneiss. Made nip of micaceous scales, with grains of 
quartz and some earthy matter. Record No. 238. 
J. Dunite. Olivine rock containing a little chromite. Record No. 
256. 
K, L. Yellow, clay-like alterations of dunite. Record Nos. 254, 255. 
Other analyses of altered rocks are given in the paper, and also 
analyses of associated minerals. 
I. 
J. 
K. 
L. 
Si0 2 
64.27 
16.75 
6.08 
.89 
1.74 
.25 
.89 
3.09 
4.97 
1.32 
.05 
40.11 
.88 
1.20 
6.09 
48.58 
40.18 
1.35 
10.97 
40.04 
3.17 
12.15 
ALOo 
Fe 2 3 
FeO 
MgO 
43.84 
42.97 
CaO 
Na 2 
K 2 
H.,0 (Ism.) 
2.74 
2.01 
none 
2.14 
none 
Ti0 2 . 
P„0« 
Cr 2 3 
.18 
1.41 
MnO 
.07 
Chromite . . 
.56 
.17 
100. 37 
100. 34 
99.76 
100. 64 
