CLARKE.] 
IGNEOUS AND CRYSTALLINE HOCKS. 
183 
Rocks P to T, from the Silverton quadrangle, arc described by 
F. L. Ransome in Bull. 182. 
P. Altered andesitic breccia, White Cloud mine. Contains quartz, 
kaolin, pyrite, rutile, and some undeterminable minerals. Analysis 
by George Steiger, record No. 1886. 
Q. Latite, country rock, Polar Star mine, Engineer Mountain. SB. 
3 of vaalase. Contains labradorite, orthoclase (?), quartz, diopside, 
chlorite, calcite, serpentine, kaolin, magnetite, hematite, apatite, rutile, 
and leucoxene. Mainly feldspar and quartz. 
R. Altered latite, same locality as P, wall rock of vein. Contains 
mainly quartz and kaolin, with diaspore, pyrite, sericite, rutile, and 
apatite. 
S. Monzonitic porphyry, near Yankee Girl mine. Adamellose. 
Contains albitc, quartz, orthoclase, chlorite, calcite, sericite, iron ores, 
pyrite, and apatite. 
T. Altered monzonitic porphyry, near National Belle mine. Con- 
tains quartz, kaolin, pyrite, diaspore, sericite, apatite, and rutile. 
Analyses Q to T by H. N. Stokes, record No. 1888. 
Si0 2 
A1 2 3 
FeA 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl05°.... 
H 2 above 105° 
Ti0 2 
C0 2 
PA 
so 3 
s 
FeS 2 . 
MnO 
BaO. 
SrO . 
85. 49 
5.49 
.23 
.25 
none 
.27 
none 
none 
.46 
3.07 
.63 
none 
.07 
.46 
3.43 
none 
.07 
99. 92 
Q. 
55. 61 
16. 40 
5.44 
2.37 
3.25 
5. 85 
2.61 
3.77 
.46 
1.51 
1.10 
1. 33 
.45 
trace 
.0!) 
.03 
.05 
trace 
100.32 
64. 79 
18. 93 
none 
none 
none 
.43 
.15 
.24 
.50 
5. 39 
1.21 
none 
.51 
7.19 
none 
.06 
trace 
trace 
99.40 
s. 
58. 78 
13.52 
1.70 
2.27 
3.29 
4. 31 
3.24 
4. 06 
.25 
1. 57 
.99 
3. 49 
.53 
L. 56 
trace 
.12 
.05 
trace 
99. 73 
::;. (ii 
13.97 
none 
none 
^none 
.31 
.04 
.06 
. 58 
4. IS 
.60 
none 
.33 
5. 62 
trace 
.04 
trace 
trace 
<>;>. 34 
