:larke.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
107 
Q. Mica-dacite-porphyry, Bunsen Peak. Analysis by Whitfield, 
No. 419, hitherto unpublished. Reported by [ddings as containing 
oligoclase-andesine, quartz, biotite, little magnetite, apatite, and zircon. 
R. Mica-dacite-porphyry, Birch Hills. Like Q in composition. 
Analysis by Whitfield, No. 718, hitherto unpublished. 
S. Hornblende-mica-andesite-porphyry, Fan Creek. Analysis by 
Whitfield, No. 713, hitherto unpublished. Reported by Iddings as 
containing andesine-oligoclase, hornblende, and biotite, in a ground- 
mass of feldspar (probably oligoclase and orthoclase), with a little 
magnetite, biotite, and hornblende. 
T. Hornblende-mica-andesite-porphyry, Gray Peak. Analysis by 
Whitfield, No. 715, hitherto unpublished. Composition similar to 
what of S. 
Q. 
R. 
T. 
s. 
SiO Q 
70.52 
15.85 
2.28 
.36 
.09 
2.59 
3.93 
3.43 
.35 
trace 
.17 
.09 
trace 
.29 
70.24 
17. 36 
1.38 
.79 
.53 
2.74 
3.69 
2.65 
.71 
trace 
trace 
none 
none 
trace 
none 
none 
65. 63 
17.00 
2.55 
1.19 
2.03 
3.48 
4.42 
1.64 
2.00 
trace 
.07 
none 
.04 
trace 
trace 
.27 
65. 64 
17. 29 
3.07 
1.29 
1.78 
1.98 
5.77 
2.44 
1.03 
none 
.23 
trace 
.04 
trace 
trace 
.17 
AL0 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 
Ti0 2 
P„Ca 
MnO 
Li 2 
so 3 
CI 
co 2 
99.95 
100. 09 
100. 32 
100. 73 
