CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
35 
CONNECTICUT. 
A. Olivine-basalt, main flow, Pine Hill, South Britain. Contains 
plagioclase, pink augite, olivine, and magnetite. The rock is quite 
fresh. 
B. Olivine-basalt, anterior flow, SouthBritain. Contains plagioclase, 
uralitized augite, olivine, and magnetite. Rock much altered and con- 
taining numerous amygdules of calcite and prehnite, stained by iron. 
Rocks A and B studied by W. H. Hobbs, who furnishes the petro- 
graphic data. Hitherto unpublished. Analyses by W. F. Hillebrand, 
record No. 1842. 
C. Basic pitchstone (tachylyte), from the so-called " ash-bed" north- 
east of Meriden. Described by Emerson in Bull. Geol. Soc. Amer., 
vol. 8, p. 77. Analysis by H. N. Stokes, record No. 1641. 
Si0 9 
Fe 2 3 
FeO.. 
MgO. 
CaO- 
Na 2 0. 
H 2 above 105 c 
Ti0 2 
NiO. 
MnO 
SrO. 
BaO. 
CO, 
FeS 2 orFe 7 S 8 a. 
52.40 
13.55 
2.73 
9.79 
5.53 
10.01 
2.32 
.40 
.62 
1.05 
1.08 
.12 
trace 
.26 
none 
trace? 
none 
.13 
99.99 
47.52 
13.91 
7.06 
3.76 
6.84 
5.71 
3.06 
.77 
1.75 
4.55 
1.19 
.15 
trace 
.18 
none 
trace 
trace 
3.68 
100. 13 
46.86 
13.96 
5.23 
4.67 
7.69 
9.42 
1.85 
2.02 
1.29 
3.43 
1.13 
.15 
trace 
trace 
.03 
trace 
2.19 
trace 
99.92 
a Calculated as pyrite. 
