110 | Geology of Deerfield, &e. 
as will be more particularly mentioned hereafter. Globular 
concretions of greenstone are common in this amygdaloid, — 
several inches in diameter, and of greater specific gravity than 
the other parts of the rock. A great number of columns occur 
in the same range, having from three to six sides. Some of 
them are quite regular, and are well articulated, exhibiting at 
their joints considerable concavities and convexities. They 
are from one to thirty feet long, and, in their natural pssition, 
incline a few degrees to the east, as may be seen in the view 
of strata with the map. A few have been noticed that make 
lateral curves. One of these hexagonal columns measures at 
one end as follows :—Diagonals, 27, 29, and 293 inches ; sides, 
163, 133, 113, 17, LI4, and 16% inches. The convexity of 
this column isa little more than an inch. The best instances 
of these prisms occur one mile east from the village of Deer- 
field. : 
Masses of greenstone are found at considerable distance 
from the range, among the puddingstone. One has been 
noticed weighing many tons, a hundred rods from the range of 
nstone, and on much higher ground. Some of these 
scattered fragments contain chalcedony. A specimen of pe- 
trosiliceous porphyry has been found among the same pud- 
dingstone, and also a mass of singular, though not well defined, 
amygdaloid, whose base is similar to wacke, and the im 
substances are calcareous spar, chlorite, and green earth. _ 
The elevation in the north part of Sunderland, called Toby, 
from 800 to 900 feet high, is chiefly conglomerate, red, brow? 
or greenish, which, in some parts, alternates with chlorite 
slate, secondary argillite, and a sandstone that seems to be 
passing into gray wacke slate. Some of the imbedded masses 
in this puddingstone are quite large, its cement is frequently 
calcareous, its aspect is singular, and it is very different from 
the puddingstone before described, on the opposite side of the 
river. At the foot of this mountain, in the bottom of Com- 
necticut river, distinct impressions of fish are found on @ 
schistose rock, like the one above mentioned as passing into 
gray wacke slate. This same species of slate occurs in Se¥® 
ral other places at the bottom of Connecticut river, as at the 
