CLARKE. J 
IGNEOUS AND CRYSTALLINE ROCKS. 
253 
I. Typical diabase, 1 mile north of Bella Vista ranch houses, San 
Mateo County. Andose. Contains plagioclase, augite, olivine, apatite, 
ilmenite, and magnetite, with secondaiy serpentine, chlorite, iron ores, 
calcite, analcite, and natrolite. 
J. Diabase, basaltic facies, Mendigo Hill, San Mateo County. ' And- 
ose. Contains plagioclase, augite, olivine, ilmenite, and magnetite, 
with secondary calcite, serpentine, chlorite, iddingsite, iron oxides, 
analcite, and natrolite. 
Rocks I and J are described by Haehl and Arnold in Proc. Amer. 
Phil. Soc, vol. 43, p. 16. Analyses by E. T. Allen, record No. 1958. 
K. Bronzite-olivine-aleutite, south end of Panamint Range. Andose. 
Contains plagioclase, bronzite, and olivine in a glassy to microcrys- 
talline groundmass carrying much magnetite. 
L. Hornblende-quartz-diorite, Fremont Peak, Mojave Desert. 
Contains hornblende, plagioclase, subordinate quartz, and apatite, with 
secondary muscovite and epidote. 
M. Alaskite, Fremont Peak. Toscanose-tehamose. Essential min- 
erals, quartz and orthoclase. 
Rocks K, L, M collected and described by J. E. Spurr. Hitherto 
unpublished. Analyses by W. F. Hillebrand, record No. 1881. 
i. 
J. 
K. 
L. 
M. 
Si0 2 
50.12 
18.52 
2.47 
4.11 
2.68 
8.99 
5.22 
1.46 
1.64 
3.09 
1.33 
49.60 
16. 56 
4.28 
4.44 
5.38 
9.22 
3.31 
1.25 
1.44 
2.58 
1.86 
53.98 
17.86 
4.61 
2.27 
3.30 
7.55 
4.19 
2.59 
.56 
.50 
1.10 
trace? 
.21 
.61 
.17 
.01 
52. 55 
17.61 
4.24 
4.98 
4.17 
8.02 
3.41 
1.49 
.25 
2.13 
.86 
trace? 
none 
.36 
76.26 
A1 2 3 
13. 43 
Fe,0, 
. 11 
FeO 
.06 
MgO 
.04 
CaO 
1.06 
MnO 
K 2 
2.95 
5.44 
H 2 at 105° 
.19 
H 2 above 105° 
.51 
Ti0 2 
.07 
Zr0 2 
trace 
co 2 
none 
P 2 5 
.18 
.08 
.30 
•17 
trace 
so, 
s 
.02 
trace 
Cr 2 3 
trace 
trace 
.03 
MnO 
.08 
.13 
.14 
.28 
trace 
.23 
.02 
.04 
none 
none 
SrO 
.03 
BaO 
.02 
.05 
.10 
Li 2 
trace 
99.91 
100. 55 
100. 06 
100. 38 
100. 25 
