: 
240 Dr. Cooper on Volcanoes 
extends southward from Massachusetts near Vermont, to 
that part of Connecticut, East and west rocks at New Ha- 
yen, consist of columnar greenstone. 
roceeding southward, the trap or greenstone rocks in 
New Jersey that form the margin of the Hudson river, de- 
- seribed by Dr. Samuel Ackerley, in his geology of the Hud- 
son river, p. 32, aud that cover the old red sandstone, are 
indubitably volcanic; figurate columnar quadrangular, pent- 
angular, hexangular, basalt, with greenstone and amygda- 
loid. 
From thence to the falls of the eatin 1 bien had no 
opportunity of examining persona 
At the falls of Passaic I spent some time in examining 
the rocks: I have no scruple in pronouncing them basalt of 
all textures, appearances and composition—compact—po- 
rous with prehnite, and carbonat of lime and zeolyte —figu- 
rate in tribedral, tetrahedral, but chiefly in’ pentagonal 
Rpsmere some dull when struck, some ringing. This mass 
of fleetz is poured over the old red sandstone. In very 
many places, this undermost rock is porous and manifestly 
cmaeeaalee place of contact and for some inches downward. 
Of this appearance, among others, I have specimens too de- 
cided. to. leave.any- doubt of their igneous origin to those 
who will make an honest use of their eyes. 
This trap formation, as it is-called, extends: about 40 
miles from the Hudson toward the Del laware; I entered it 
at three several and distant places ; I collected every where 
porous basalt with carbonat of lime, prehnite, and occasion- 
ally zeo! vies as well ascominon basalt, greenstone and figu- 
rate basalt, all graduating into and. connected with each 
other. I examined this chain, in three places at about ten 
miles distance from each other, and I am satisfied 
nature of the rock. . Whether it crosses the Delaware I do 
not know, but I think not. 
On the road side from Princeton: to, Brunswick ini Deve 
Jersey, is a manifest Basalt formation, consisting oer 
of figurate clinkstone. I have not traced it. 
About eleven and a half miles from Philadelphia, de- 
seending a hill, on the Ridge turnpike road, there is a for- 
mation of about one’ hundred yards. broad, that I have trac- 
ed from thence ake the Scuylkill, for a considerable dis- 
tance beyond the Gulph mills in Montgomery County. It 
