CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
45 
The following rocks, from Cecil County, have been studied by 
A. G. Leonard. Descriptions as yet unpublished. 
G. Quartz - biotite - hornblende - dioritc, near the foundry on Stone 
Run. Granitic in appearance. 
H. Quartz - biotite - hornblende - diorite, near Porter's bridge on 
Octoraro Creek. 
I. A true diorite with very little quartz, Stone Run, one-half mile 
northwest of the mill near Rising Sun. 
J. Norite, three-fourths of a mile northwest of McKinsey's mill. 
Analyses by Hillebrand, record No. 1755. 
Si0 2 
A1 2 8 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl05° ... 
H 2 above 105° 
Ti0 2 
P 2 5 
Zr0 2 
V 2 3 
Cr 2 3 
NiO,CoO 
MnO 
SrO 
BaO 
Li 2 
FeS 2 
CO, 
G. 
100. 07 
ii. 
58.57 
55.16 
16.10 
17. 51 
2.89 
2.62 
6.12 
5.83 
2.33 
4.35 
7.39 
8.50 
2.11 
1.83 
1.01 
1.08 
.21 
.18 
1.27 
2.01 
1.41 
.64 
.37 
.21 
.09 
.02 
.02 
.04 
none 
trace 
none 
.01 
.18 
.15 
trace 
trace 
trace 
trace 
trace 
trace 
trace 
.03 
none 
none 
100. 17 
44.04 
20.01 
4!22 
8.61 
5.01 
11.68 
1.24 
.15 
.11 
1.90 
2.24 
.52 
.10 
.05 
none 
.01 
.28 
none 
none 
trace 
.25 
none 
100. 42 
48.02 
20.01 
1.13 
7.29 
10.05 
11.42 
.51 
.05 
.10 
,57 
.23 
trace 
none 
.02 
.03 
.01 
.18 
none 
none 
trace 
.11 
.25 
99.98 
