46 Geology, &c. of the Connecticut. 
this range at the north end of Mount Tom, and on the op- 
site bank KS rises again precipitously and forms Mount 
Holyoke... T is | found, with a nice sextant, to be eight 
hundred eee cee feet above Connecticut river. North 
of Holyoke the greenstone is curved towards the right and 
continues of nearly the same elevatioa until it terminates 
near the north-west corner of Belchertown, having reach- 
ed the primitive region. 
pave or ten miles north-westerly from this point, we find 
a narrow ridge of greenstone commencing, and pursuing a 
course toipiteshis west of north, it passes through Sun- 
derland, crosses hommennens river, runs through Deerfield, 
crosses Deerfield river, and extending through a part of 
Greesmeld. Saintes at the falls in Connecticut river. A 
few rods east of this termination another range commenc- 
es and runs east of north through Gill, with some interrup- 
tions, till it reaches its extreme northern point in North- 
eld, two miles south of the primitive greenstone. 
‘Tt will be seen by the map, that these greenstone ridges 
separate the old red sandstone from the coal formation 
nearly the whole distance from Berlin to Nor : 
So rocks of the coal formation are frequently found |} 
ve the greenstone. The range of green stone in Sun- 
peasy is very narrow, and being in an unfrequented spot 
along the western margin of Mount Toby, it was a long time 
before I discovered its existence. Having once found it, . 
however, it was traced, without much difficulty, except. 
what an almost impassable precipice presented. It is from* 
ten to eighty rods wide. As you ascend the mountain from 
the west, you first pass over a formation of old red sand- 
stone, which is here a coarse pudding-stone. Next you 
come upon the greenstone, most of which is a pec 
and is, so far as hand eocines will enable us to decide, 
the real toad stone of Derbyshire. Immediately east of 
the green-stone you find the coarse, brownish red, and the 
fine, fissile, argillaceous, gray and red sandstone slates. of 
o coal formation. These uniformly rise in higher le 
n the greenstone; even one hundred or one bundaet i 
and fifty feet above it. As you pass along in the direction’ 
of the greenstone ridge, these precipices are not more than 
ten feet from you on one hand, and the greenstone at no 
