Geology, Sc. of the Connecticut. 5S 
such a variety. A locality of it may be foand one hun- 
dred rods north of the wi nh il river bridge in Deerfield, 
at the western foot of the trap ra 
The columnar tendency of our greedutone has often been 
noticed. It may be seen in almost every ridge in a 
better ones a mile san of the village of ‘Deewield, a quarter 
ofamile north of the locality of chabasie, enaslciinie; c.men- 
tioned in the Jour. of Science Vol. I. p. 115. They have 
from three to six sides, are articulated, ‘the points varying 
from one to three feet in diameter, and of the same height, 
exhibiting handsome convexities and corresponding concav- 
ities. Halfa mile south of this spot may be seen columns 
—— to the right and left as they ascend ; thus forming 
a portion of an arch. The geologist, who traverses this 
ridge, can navdly avoid tra oe io bonginatigpe the giant’s 
causeway, and the Hebride , 
Some of the less perfect bolts have a remarkably fis- 
sile tendency; forming good hand specimens of pseudo- 
green-stone slate. Globular distinct concretions of this 
rock are not unfrequent among the amygdaloid ; composed 
of concentric coats of greater specific gravity than the resf 
of the rock. I have noticed them in Deerfield. and on the 
are abundant, and from two to twelve inches in diameter. 
he general aspect of our greenstone, where it has been 
long exposed to the weather, is reddish brown. When 
newly broken it is greenish, often somewhat lively. Some- 
times it is greyish black, and, very rarely, has the color 
of a brick that has been burnt very hard. This variety is 
compact and the a It is often the fact, 
indeed, that the two ingredients in other varieties, are not 
to be discovered by the naked eye, or with an ordinary lens. 
A question then occurs, whether some of the varieties of 
this rock are not genuine basalt? Certainly some of them 
answer the description of that rock, so far as external char- 
acters are concerned, to say the least, as well as of oe 
stone. And, indeed, if “greenstone and basalt may not 
unfrequently be seen passing into each other in the 
same stone, as D’Aubuisson and Dolomieu have observ- 
ed? (Bakewell’s Geology, p. 119,) there seems no rea- 
a 
