270 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY, 
[no. 22 
O. Augite-belugite, Skwentna River, near Haj^es River. Heasose. 
Dike. Contains essential feldspar, intermediate between andesine and 
labradorite, augite, and some hornblende. Also a considerable amount 
of pyrite. P. R. C. 1274. 
P. Tordrillite, Tordrillo Mountains. Alaskose. Dike. Contains 
phenocrysts of quartz, orthoclase, anorthoclase, and anorthoclasej 
albite. Groundmass consists of quartz and orthoclase. No dark min- 
erals except very small quantities of secondary hornblende. P. R. C. 
1270. 
Q. Augite- aleutite, near Kalinai Pass, Aleutian Peninsula. Andose. 
Lava. Chiefly labradorite, tending- toward andesine, with a consider- 
able amount of pale-green augite. P. R. C. 1277. 
R. Plagioclase-scapolite-biotite rock, Skwentna River, 12 to 15 miles 
above its mouth. Tonalose. Dike. Described by Spurr in Amerl 
Journ. Sci., 1th series, vol. 10, p. 310. Essential constituents andesine- 
oligoclase, scapolite (dipyre) and biotite, with accessoiy apatite and 
zircon. P. R. C. 1273. 
S. Tonalite-aplite or yukonite. Yukonose. Yukon River, above 
Fort Hamlin. Hitherto undescribed. Consists essentially- of quartz 
and soda-lime feldspars. 
o. 
Si0 2 
A1A 
FeA 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 110 c 
TiO, 
PA 
MnO 
BaO. 
SrO . 
Li 2 
C0 2 . 
S«... 
CI... 
50. 23 
19.46 
4.21 
4.20 
3.59 
10.39 
3.08 
1.32 
.16 
1.01 
1.30 
.41 
.07 
.04 
trace 
trace 
.25 
.02 
99.74 
75.84 
13. 38 
1.45 
.10 
.07 
3. 33 
4.73 
.18 
.71 
.09 
trace 
trace 
trace 
trace 
trace 
none 
99.88 
56. 03 
18. 31 
3.47 
4.42 
3.64 
7.43 
3.60 
1.18 
.12 
.31 
1.24 
.13 
.11 
trace 
trace 
trace 
none 
trace 
'.)!i 
k. 
62. 78 
17.16 
1.96 
2.31 
2.32 
4.84 
4.11 
2.15 
.24 
.88 
.56 
.15 
.06 
.04 
trace 
trace 
none 
.02 
trace 
99. 58 
74.79 
12.51 
1.19 
.31 
3.58 
5. 10 
.21 
.09 
1.03 
.17 
trace 
trace 
none 
nonl 
none | 
.58 
99.64 
"Whether S or S0 3 was not determined. 
