:lakke.] 
IGNEOUS AND CRYSTALLIJS E ROCKS. 
157 
6. TENMILE DISTRICT. 
Rocks described by Cross in 14th Ann., page 165. Analyses made 
in the Denver laboratory, A and C by W. F. Hillebrand, B by L. G. 
Eakins. 
A. Quartz-hornblende-mica-porphyrite, Gold Hill. Contains pla- 
ioclase, hornblende, biotite, and quartz, in a groundmass of quartz, 
irthoclase, and a little plagioclase. P. R. C. 510. 
B. Quartz-porphyrite, Sugar Loaf. Contains plagioclase, biotite, 
ind quartz, in a groundmass of quartz and orthoclase. P. R. C. 509. 
C. Quartz-porphyrite, Chicago Mountain. Contains plagioclase, 
Drthoclase, biotite, and quartz. P. R. C. 508. 
Si0 2 ._ 
A1A- 
Fe 2 3 
FeO.. 
MgO. 
CaO.. 
Na 2 . 
K 2 0.. 
H 2 above 110° 
Ti0 2 
^A 
MnO 
SrO 
BaO 
Li 2 
CO, 
63.66 
17.05 
1.97 
2.62 
1.99 
3.89 
4.13 
3.09 
1.19 
andet. 
.27 
.14 
none 
100.08 
p.. 
67.29 
15.78 
1.86 
1.97 
.72 
2.36 
3.77 
3.55 
2.10 
none 
.28 
.21 
none 
trace 
.27 
100. 16 
C. 
68. 30 
16.24 
1.60 
1.63 
1.05 
2.79 
3.90 
3.52 
.71 
undet. 
.13 
.12 
.04 
trace 
trace 
100. 03 
