CLARKE. 
IGNEOUS AND CRYSTALLINE KOCKS. 
53 
The following rocks, from Cecil County, are described by A, G. 
Leonard in Amer. Geologist, vol. 28, p. L35. 
(J. Quartz-mica-hornblende-diorite, near the foundry on Stone Run. 
Bandose. Contains hornblende, biotite, quartz, plagioclase, and a 
little orthoclase, with accessory zircon, apatite, titanite, and magnetite, 
and secondary chlorite and epidote. 
H. Like G, near Porter's Bridge on Octoraro Creek. Bandose. 
I. Hornblende-diorite poor in quartz, three-fourths mile northwest 
of Rising Sun. Corsose. 
J. Norite, 1 mile west of Oak Grove schoolhouse. Kedabekose. 
Contains hypersthene, I^townite, a little diallage, apatite, magnetite, 
and secondary hornblende. 
Analyses by Hillebrand, record No. 1755. 
Si0 2 .. 
A1A- 
Fe 2 3 
FeO.. 
MgO. 
CaO.. 
Na 2 0. 
K 2 0.. 
p 2 above 105° 
Ti0 2 
PA 
Zr0 2 
v 2 o 3 
Cr 2 3 
NiO, CoO 
MnO 
SrO 
BaO 
Li 2 
FeS 2 
CO, 
G. 
H. 
I. 
J. 
58. 57 
55. 16 
44. 04 
48. 02 
16.10 
17.51 
20.01 
20.01 
2.89 
2.62 
4. 22 
1-13 
6.12 
5.83 
8.61 
7. 29 
2.33 
4. 35 
5.01 
10.05 
7.39 
8.50 
11.68 
11.42 
2.11 
1.83 
1.24 
.51 
1.01 
1.08 
.15 
.05 
.21 
.18 
.11 
.10 
1.27 
2.01 
1.90 
.57 
1.41 
.64 
2. 24 
.23 
.37 
.21 
.52 
trace 
.09 
.02 
. 10 
none 
.02 
.04 
.05 
.02 
none 
trace 
none 
.03 
none 
.01 
.01 
.01 
.18 
.15 
.28 
.18 
trace 
trace 
none 
none 
trace 
trace 
none 
none 
trace 
trace 
trace 
trace 
trace 
.03 
.25 
.11 
none 
none 
.none 
.25 
100. 07 
100. 17 
100. 42 
99.98 
