clarke] IGNEOUS AND CRYSTALLINE RO.CKS. 159 
COLORADO. 
1. DENVER BASIN. 
Rocks described by Cross in Mon. XXVII. Analyses A, B, D, and 
E by L. Gr. Eakins, C by W. F. Hillebrand. All but A were made 
in the Denver laboratory. 
A. Dolerite, dike near Vahnont. Shoshonose. Contains aUgite, 
plagioclase, olivine, orthoclase, and biotite, with accessory magnetite 
and apatite. Record No. 1145. P. R. C. 531. 
B. Augite separated from A. P. R. C. 105. 
C. Basalt, Table Mountain, lower capping sheet. Shoshonose. Con- 
tains plagioclase, orthoclase, augite, magnetite, and apatite, with 
olivine much serpentinized. Sp. gr., 2.83, 22.5°. 
D. Basalt, earlier flow, south slope of North Table Mountain. 
Shoshonose. Contains augite, olivine, plagioclase, probably ortho- 
clase, magnetite, apatite, and a little biotite. P. R. C. 535. 
E. Augite-mica-syenite, from north fork of Turkey Creek, Jefferson 
County. Shoshonose. Contains orthoclase, augite, biotite, rhombic 
pyroxene, hornblende, plagioclase, quartz, apatite, and magnetite. 
Sp. gr., 2.857, 29.5°. P. R. C. 532. 
A. 
B. 
C. 
D. 
E. 
Si0 2 
48. 25 
16. 73 
3.99 
6.28 
5.77 
8.32 
3.24 
4.08 
1.72 
.89 
.68 
trace 
.01 
.08 
.12 
49. 10 
.7. 95 
8.30 
12.37 
22. 54 
trace 
trace 
52. 59 
L7.91 
3.81 
5.18 
4.11 
7.24 
2.94 
3.83 
1.24 
.84 
.14 
trace 
49. 69 
18.06 
2.64 
6.19 
5. 73 
S. 24 
2.99 
3.90 
.91 
.85 
.81 
.13 
56. 90 
AL0 3 
IS. 50 
Fe,0, 
. 17 
FeO 
4.61 
MgO 
CaO..~ 
5.10 
6.17 
Na 2 
2. 99 
K 2 
4. 14 
H 2 
.51 
Ti0 2 
.19 
P 2 5 
. 79 
MnO 
trace 
BaO 
CI 
.05 
.13 
trace 
S0 3 
100. 16 
100. 26 
99.88 
100. 27 
100. 07 
