Geology &c. of the Connecticut. 23 
that direction, as we have already suggested; although it 
may not yet have made its appearance above the later rocks 
the whole distance. 
is rock is somewhat Protean in its appearance; yet 
not very difficult in most cases to be distinguished by care- 
ful observation. The following varieties have been noticed 
in this region. 1. A variety already referred to, as occur- 
ring in Leverett, near the pudding-stone; which is scarcely 
any thing more than imperfectly Jimpid quartz, divided into 
distinct rhombic concretions, about an inch thick, and three 
or four across the outside, slightly spangled or glazed with 
mica. 2. Very much like the last, except that it does not 
divide into complete rhombs, but is only separated by seams 
oblique to the direction of the strata, and nearly perpendic- 
ular to the horizon*—Locality, West-River mountain in 
Chesterfield ie plas es 3. Divided as the feat by 
e 
becomes a mere siliceous sand, blended closely with the 
mica. Surface rarely waving—Locality, Whately, Con- 
way, &c. 4. Not regularly divided in any direction, ex- 
cept that of the strata, and much less fissile than the last. 
Mica scattered in fine scales through the mass, and the silex 
more abundant than the last—Rock breaking into huge 
blocks, from one to three feet thick, and often forming, like 
greenstone, abundance of debris. Locality, West-River 
mountain and Deerfield. These four varieties occur on the 
i 
ised, forming a kind of glazing “ath ne aspect of ere ‘ 
mica in somewhat distinct layers—quartz predominating, 
and mica not very well characterised—abounding in garnets. 
—Locality, Plainfield, Hawley, Conway, &c. 7. Passing in- 
to talcose slate—mica abundant, having somewhat of a ae 
brous aspect and connected with talc. Northfield and Haw-_ 
ley. 8. Passing into argillite. Locality, Leyden, Ches- 
*<cWhen one set of parallel planes crosses anot! Se , are both seteto be cal- 
led strata, or neither, or only one of them >? _ Greenough’ s Geology, Essay 1. 
