CLARK E.] 
IGNEOUS AND CRYSTALLINE HOCKS. 
ALASKA. 
267 
Rocks A to H, inclusive, were collected by (J. F. Becker, who fur- 
nishes the petrographie data. A, B, C, D, F, and II are described by 
Becker in the 18th Ann., Part 3, p. 7. Analyses by Hillebrand, record 
No. 1585. 
A. Augite-bronzite-andesite, Delarof Harbor, Unga Island. Andose. 
Greenish black. Contains plagioclase, near labradorite, with much 
smaller proportion of augite and bronzite, in a groundmass of plagio- 
clase, with a little glass and much light-green indeterminate material. 
B. Augite-bronzite-andesite, St. Augustine Volcano, Cook Inlet. 
Placerose. Purplish gray. Contains labradorite, augite, and bronzite 
in a groundmass of plagioclase and magnetite. 
C. Quartz-porphyry, bed of Bear Creek, 4: miles from its mouthy 
Turnagain Arm, Cook Inlet. Dacose. Resembles D, with more 
feldspar and less quartz. 
D. Quartz-porphyry, east of mouth of Indian River, Sitka, Baranof 
Island. Sitkose. Contains plagioclase, quartz, a little pyroxene, 
and some carbonaceous matter, with secondary quartz, calcite, and 
muscovite. 
E. Diorite, head of Captains Bay, Unalaska Island. Tonalose. 
Contains plagioclase, biotite, hornblende, chlorite, magnetite, and 
sometimes tourmaline. 
Si0 3 .. 
A1A- 
Fe 2 3 . 
FeO.. 
MgO . 
Ca( ) . . 
Na 2 0. 
H,OatllO°... 
H 2 above 11 C 
Ti0 2 
PA 
VA 
NiO 
MnO 
SrO 
BaO 
Li 2 
C0 2 
C 
FeS, 
56. 63 
16. 85 
3.62 
3.44 
4.23 
7. 53 
3.08 
2.24 
.80 
.51 
.67 
.16 
.04 
trace? 
.23 
trace 
.09 
trace 
none 
B. 
60.40 
16. 85 
1.88 
3.72 
3.82 
7.25 
3.80 
.77 
. 09 
.20 
.61 
.16 
.02 
.12 
trace 
.06 
trace 
none 
C. 
62.92 
14.29 
.84 
4.66 
3. 14 
2.72 
4.30 
1. 39 
.22 
2.84 
.84 
.13 
i). 
65.94 
13.74 
.49 
5.21 
2.33 
2.87 
2.80 
1.63 
.21 
2.59 
.80 
.21 
trace 
.15 
trace 
.10 
trace 
1.24 
06 
100. 14 
08 
32 
trace? 
.11 
trace? 
.12 
trace 
.59 
.20 
.41 
99.87 100.10 100.25 
E. 
58. 63 
16.23 
1.91 
4.20 
4.28 
6. 59 
3. 51 
2. 09 
;15 
1.17 
.74 
.20 
.02 
.11 
trace 
.06 
trace 
none 
04 
99. 93 
