242 Dr. Cooper on Volcanoes 
The fletz trap formation of our r north eastern states, eXx- 
tends higher than Deerfield, aang bap ; and perhaps 
to the New-Hampshire line ; s* see Mr. cock’saccount 
of that region in Prof. Silliman’s hiae. se of Science. 
These rocks contain enters ae carbonat of Lime, &c. 
I have specimens. Part r. H’s account will be found to 
afford strong confirmation . ot of Dr. Cooper’s ape 
I know nothing of the brown Augit mentioned by 
pote ~ Pine rock. The only augit I have seen, as an 
American specimen, was in the possession of Dr. Bigsby 
of the British staff from the neighbourhood of Montreal. I 
think New-Haven is the most southerly point of this forma- 
tion in Connecticut. East and West rocks in New-Haven, 
which are said to be miniatures of Salisbury Craig, are com- 
posed of 8p rocks based on what is esteemed the old red 
sandstone ‘hey are columnar, with considerable regu- 
larity, containing prehnite in seams and nodules, with Zeo- 
lites; and in one case I met with some quartz crystals. 
The : appearance of these Fi mounts seems like that of the 
Palisadoes on the Hudson, which however I have seen 
only at a distance. The forms ofthe rock are various; 
more commonly trapezoidal : they are used with their natu- 
ral surfaces exposed externally in building the walls of a 
church in New-Haven. They are often found in thin La- 
mina, which in place have their edges vertical, and are ex- 
cellent clinkstones ; they are frequently irregular. 
ut two or three miles east in East-Haven, there are 
numerous parallel ridges of similar rock, but for the most 
part, without any regular jointed structure abounding in 
different places with agates, chalcedony, and amethystine 
quartz geodes,t carbonat of lime, analcime, Prehnite and 
green earth. In some spots this basalt, if basalt it be, is 
found in spherical balls. In one or two instances it alter- 
nates with the sandstone which has been mentioned ; an 
where the two come in contact, the sandstone is domewhat 
altered: whether by heat or not I do not pretend to say. 
ai 
Look at Hitchcock’s map of the Connecticut river in 
1 Sillim. Journ. 105, for the Greenstone breaking through 
* Tt extends a few miles into Vermont not New-Hampshire.—Ep. 
+ Are not the Geodes of Oberstein, Lava? T.C. 
scncingntlaanpiattitinidit naa i ioaei ieee, Sli 
iene lcsttnctreatercsee: 
