160 
GEOLOGY OF THE SECOND DISTRICT. 
Another important mass of granular quartz, in this last range, appears fifteen miles south 
in Dalton, in close proximity with the primary of the Hoosic mountain range. Monument 
mountain, in Stockbridge, is another great mass of this rock ; and still others exist. All the 
examples of this rock are insulated, or surrounded by other rocks, as if they were great beds 
in the latter. 
The stratification of this rock is more or less obscured by the crystallization of its layers. 
It furnishes but few instances of contortion, while, as has been stated, they are extremely 
common in the limestone which lies in immediate contact with it. One beautiful instance of 
curvature and fracture has been noticed in this rock in Williamstown, on the west side of the 
hill opposite the burying ground. The section No. 52 is a representation of the fracture and 
curvatures here referred to : 
52. 
This curious and highly interesting case of contortion occurs in the western slope of the 
hill. The strata dip to the east as usual ;* and this mass of quartz, which is more slaty than 
usual, lies between two beds of limestone. In this instance, there is the uplift accompanied 
with the effects of lateral pressure, which formed not only a double arch, but here so power¬ 
ful as to break the inass nearly in the centre between the two arches, and the portion on the 
north side is thrust up so as to override and overlap the other. At the line of fracture, the 
surface is partly crushed and partly rolled into short cylindrical pieces, giving at the same 
time to the adjacent laminae many short and unequal curves. 
This I take to be an instance in which the flexures of the strata have been really produced 
by lateral pressure; it certainly does not belong to a doubtful case, in consequence of the 
fracture ihe layers have sustained. In this instance, however, it would seem that the pres¬ 
sure was confined to a few feet thickness of rock ; for from what appears, about eight or ten 
feet was raised up from the strata beneath, and to these few layers the pressure might have 
been confined. There is at least a small cavern or space beneath, which seems to have been 
formed by raising up the strata forming the roof, from those which form the floor. 
The granular quartz is the least regular in its occurrence, of any of the rocks of the Ta- 
conic system; it generally appears in insulated mountains, surrounded apparently by other 
* The preceding cuts, Nos. 49, 50, 51 and 52, were not reversed by the engraver, and hence the dip and other characters are 
misrepresented. 
