228 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[bull. 1G8. 
Rocks K to S. Collected by J. E. Spurr, who furnishes the petro- 
graphic notes. All but S are to appear in the 21st annual. Analyses 
by Stokes, record Nos. 1809 and 1822. 
K. Alaskite, Chilkoot Pass. Dike in granite. Contains quartz, 
orthoclase, and some twinned feldspars, accessory zircon, actinolite, 
magnetite, and siderite. 
L. Alaskite-porphyry, Forty mile Creek, near Canyon Creek. Dike. 
Contains quartz, orthoclase, and some plagioclase, with accessory bio- 
tite and epidote. 
M. Alaskite, Skwentna River, 12 miles above its mouth. Dike. 
Contains quartz, orthoclase, and microcline, with no dark minerals. 
N. Alaskite, Tordrillo Mountains. Dike. Consists of quartz, ortho- 
clase, and microcline, with no dark minerals. 
K. 
L. 
M. 
N. 
Si0 2 
76. 30 
12. 50 
1 1.47 
none 
.17 
3.86 
4.67 
.18 
.32 
.05 
.07 
none 
none 
67.01 
17.91 
1.30* 
.42 
1.86 
5.33 
4.56 
.16 
.48 
.10 
.60 
.13 
none 
75. 01 
13.88 
.74 
.09 
1.00 
3.52 
4.89 
.11 
.26 
.06 
.10 
trace 
trace 
77. 33 
12.55 
.91 
.10 
.17 
3.19 
4.80 
.15 
.53 
.09 
trace 
trace 
trace 
A1 2 3 
Fe 2 0. i 
FeO 
MgO 
CaO 
Na 2 . 
K 2 
H 2 OatllO° 
H 2 above 110° 
Ti0 2 
BaO 
SrO 
Li 2 . 
99. 59 
99.86 
99. 66 
99.82 
Manganese is also present in 
traces. 
