■ ARKF..J 
IGNEOUS AND CRYSTALLINE ROOKS. 
187 
L. Diabase, east of the Sugar Loaf, Boulder Count}'. Hessose. 
Description furnished by Whitman Cross. The rock contains labra- 
dorite, orthoclase, augite, and magnetite, with small amounts of horn- 
blende, biotite, apatite, and secondary chlorite. Sp. gr. , 3.027, 21°. 
P. R. C. 166. 
M. P}^roxene separated from L. 
N. Nephelinc-tephrite, Elkhead Mountain, Routt Count}'. Unde- 
served. Sp. gr., 2.888, 12.2°. 
O. Portion of N soluble in hydrochloric acid. Recalculated to 100 
per cent. 
Analyses L to O made by L. G. Eakins in the Denver laboratory. 
Hitherto unpublished. 
o. 
Si0 2 .. 
A1 2 3 . 
Fe 2 3 . 
FeO_. 
MgO . 
CaO.. 
Na 2 . 
K 2 0. 
H 2 0. 
p 2 5 - 
s 
S0 3 ... 
CI... 
MnO 
48. 93 
20.99 
2.02 
9,36 
4.39 
8. 03 
3.06 
1.80 
1.18 
.15 
trace 
:;i 
47. 32 
6. 37 
2. 56 
14. 40 
13. 43 
16.08 
100. 22 
100.16 
46.67 
15.90 
3. 20 
7.04 
10.17 
9. 15 
3.20 
2.54 
1.64 
.64 
trace . 
.11 . 
trace . 
100. 26 
45. 51 
18.40 
s. 02 
9. 58 
6.78 
4.61 
4. 90 
2.20 
100. 00 
