& 
ee Geology, &c. of the Connecticut. 
19. Chalcedony. 
1. Common Chalcedony. At East-Haven, in greenstone. 
(Silliman.) Also in the same rock at Southington, Far- 
mington, Hadley, Sunderland, Deerfield, Greenfield, Gill, 
and indeed, in almost every greenstone hillock and ridge 
from New-Haven to Gill. Its color is light grey, deep grey, 
brownish, yellowish and greenish grey; it occurs botryoi- 
dal, mammillary, cylindrical and reniform, and is often of a 
cloudy or milky appearance, and frequently, strongly trans- 
ucent. 
2. Cacholong. In greenstone, Deerfield. It is associated 
with common chalcedony, and frequently, envelopes it, or 
constitutes some of the bands of agates. Its color is milk 
or yellowish white. é 
3. Carnelian, In greenstone, Deerfield. United with 
common chalcedony and cacholong, into which it passes. 
Its color is usually pale or yellowish red. It is not abundant. 
Also at East-Haven. sas. 
‘4, Sardonyx ? Some specimens of the carnelian in Deer- 
field greenstone, being reddish yellow and orange, appear 
to belong to this variety ; but it occurs in so small quantities 
as hardly to be worth noticing. 
Agate. This occurs at East-Haven and Deerfield ; and 
as it is composed of varieties of chalcedony and quartz, this 
seems to be the proper place to notice it. A description of 
a part of the agates occurring in these localities. has already 
been given with sufficient minuteness in the American Jour- 
nal of Science, and in Cleaveland’s Mineralogy. But since 
the publicatiog of those accounts, Dr. Dennis Cooley has 
discovered a new locality in the Deerfield greenstone, from 
which he has obtained specimens so much superior to those 
heretofore found that they deserve a particular notice. The 
following is a description of specimens in his possession. 
No. 1. Longer diameter of thé face of the agate, nine 
inches—shorter diameter, sixinches. Outer zone, green!s 
chalcedony, half an inch broad. Second zone chalcedony, 
