CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
113 
G. Basalt?, Bear Creek. Resembles A, but with a more crystalline 
groundmass. Contains plagioclase, possibly sanidine, augite, olivine, 
and iron oxides. Analysis by Chatard, record No. 1154. P. R. C. 967. 
H. Lamprophyre, between South Boulder and Antelope creeks. 
Contains porphyritic augite and olivine in a feldspathic groundmass, 
with apatite, augite, grains of iron oxide, and shreds of brown mica. 
Sp. gr. 2.96. Analysis by Eakins, record No. 1266. P. R. C. 966. 
I. Lamprophyre, hills east of South Boulder Creek. Nodules from 
a decomposed mass. Shows sanidine, plagioclase, brown mica, and 
altered olivine. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 OatllO°... 
H 2 above 110 
Ti0 2 
PA 
Cr 2 3 
NiO 
MnO 
BaO 
G. 
49. 13 
9. 05 
3. 57 
5. 05 
17.21 
5.68 
2.01 
2.24 
.84 
3.50 
.42 
.38 
.39 
trace 
.15 
.05 
99.67 
ii. 
50.82 
11.44 
.25 
8.94 
14. 01 
8. 14 
1.79 
3. 45 
.58 
. 59 
.20 
.03 
trace 
.19 
.06 
100. 49 
50. 03 
14.08 
2.92 
6.11 
10. 73 
7.46 
1.46 
2.64 
3.70 
.61 
.42 
trace 
trace 
.08 
.04 
100. 28 
Bull. 168- 
