Geology and Mineralogy of a part of Massachusetts, Ge. 5 
rocks on the surface of the earth. The fact is that the 
granite is here surrounded by gneiss or mica-slate. To 
suppose the incumbent rocks to have been worn away so as 
to show the granite, involves the fundamental point of the 
Wernerians, viz. universal formations, and a very wonder- 
ful elevation of often very small and thin portions of gran- 
ite above the common level, to form the veins in the mica- 
slate, as well as the action of causes more powerful than 
any perceived to be operating at the present time. 
The bed of granite in Middlefield is far greater than any 
other in this section. It lies in mica-slate, and is the only 
granite put down upon the map. 
Singular position of Granite—In Chester is a mass of 
Granite lying in mica-slate, of which Dr. Emmons gives 
the following representation. (See Plate 2.) 
A, is the granite, of a cuneiform shape, lying on the sur- 
face of nearly vertical strata of mica-slate. The granite is 
connected with nearly perpendicular veins of granite, Band 
C passing up through the strata of mica-slate, BD. 
2. GNEISS. 
Colored Purple. 
This rock seems to be of avery limited extent in this 
section of our country, though it is more abundant than 
granite. It occurs indeed in various places along the east- 
ern partof Berkshire Co. in smal! quantities. In Windsor, 
Peru, and Middlefield, it is found as a continuous rock, 
several miles in length, and sometimes more than half a mile 
in breadth. It is a coarse light gray, or whitish rock, con- 
sisting chiefly of feldspar. I have not noticed this rock 
in crossing either to the north or south of the towns 
just mentioned. As gneiss is found however still farther 
north, it is probably connected with this stratum which was 
not observed to show itself. In New Marlborough, about 
a mile east of the meeting house, is another appearance of 
gneiss, the extentof which is not well ascertained. I have 
put upon the map, the gneiss of the south east part of this 
section, on the authority of Mr. Hitchcock in his papers al- 
