54 Geology, Se. of the Connecticui. 
son to doubt that this fact may exist in this country as 
well asin Europe. ere I to refer to particular localities 
for rocks resembling basalt, | should mention the foot of 
Mount Tom on the north-east side, and a part of the range 
passing through Deerfield. It would not surprise me, should 
future geologists make a division of our greenstone, calling 
a part of it basalt; dividing the upper part of the ridges from 
the lower, or the eastern side from the western, or both. 
A, geologist, to be able satisfactorily to make these divi- 
sions, or to decide whether any of our rock is basalt, ought 
to have traversed extensively and observed minutely the like 
rocks in Europe; and, therefore, I leave the subject to 
abler hands. | $ 
A good locality for observing many of the varieties of 
greenstone above described within a narrow compass, is on 
the north bank of Deerfield river, about sixty rods from the 
bridge. Leta person cross the bridge to the north, and 
take the right hand road, until he comes to where the road 
‘ passes round the end of the greenstone ridge. Here he 
will first see the most common variety, having a columnar 
tendency; and a few rods beyond, the reddish brown vari- 
ety,* and in a wall, supporting the road on the right hand, 
he will find abundance of the porphyritic greenstone, hav- 
ing a somewhat stratified structure. Here, too, he will 
find some specimens covered with a ferruginous coating ; 
so much charged with iron, indeed, that efforts have been 
made to smelt it. Indeed, a mass of four or five pounds 
from almost any part of this greenstone range, when held 
by the side of a compass, will move the needle. 
It is not always the case, nor even generally, that the 
greenstone ridges that are marked as continuous on the 
map, are strictly so. They are often composed of numer- 
ous peaks or ridges, partially detached, but yet constitu- 
ting a single range when viewed at their bases. And some- 
times, when there appears to an observer passing along the 
western side of the range to be an uninterrupted wall, clos- . 
er examination will show, that it is made up of several dis- 
tinct ridges, so lapping on upon each other, and so near one 
another, that they appear continuous. ‘The mural face of 
the ridges and billocks is usually on their western side: 
but sometimes on the opposite side, as in the high moun- 
*T have aspect f gr tone fi vein in Scotland resembling this, 
except that the Scottish rock is much coarser. 
Bape ape rena piste 8 
