Granitic veins and beds in Chester, Mass. pI 
supported on the vertical edges of the strata of mica-slate. 
An area of several square rods.is exposed to examination, 
unconcealed by the soil. It is uniformly about four inches 
thick and fills the inequalities of the inferior rock. The 
vein is not in one continued plane, but projects downwards 
into the mica-slate, and gives off narrower branches which 
terminate within a few feet of the principal vein. This 
vein appears three times in an area of twenty square rods, 
though not inan unbroken mass, yet they were evidently 
once connected. : 
Another position in which granite occurs may be seen, 
fig. 2. These veins and bed were discovered in Norwich. 
The bed is five rods in length and in the thickest part 
three feet thick and about the same in width. ‘Two par- 
allel veins eight inches thick come up from below and 
unite with the bed. ‘The bed is irregular in its shape, 
aad gradually tapers each way, till it terminates in points. 
At these points, it is distinctly seen to rest on the edges 
of the strata and not to penetrate between them ; it once 
extended farther N. and S. than at present, for masses of 
granite are still seen adhering to the mica-slate for several! 
rods. Qn the east side, the rock which constituted the 
wall, is entirely broken away, and exposes the whole mas: 
to view. ‘There are many other masses or beds of granite 
which are apparently in the situation of this last, though 
it cannot be determined whether they are connected with 
veins, yet it is probable they are. It is very certain that 
in many places the principal masses of granite do not 
penetrate deep, as they can be seen to become thinner as 
they descend between the strata of mica-slate, and a few 
thin veins which I have seen, actually terminate after 
penetrating a few inches downwards. 
Fig. 3. Pl. I. represents a section of agranitic bed*. It 
rests against the mica-slate on the west, but on the east 
it is exposed to view. It is four feet thick, and is twisted 
and contorted in aremarkable manner. It contains green 
and blue tourmaline, rose quartz, emerald, cleavelandite 
and prismatic mica. One crystal of blue tourmaline is to 
be seen three inches in diameter. One of green has been 
*Iam not pleased with the common definition of beds and veins, I 
should call all the granite which occurs here, granitic veins. In some in- 
stances it is impossible to determine whether the granite is in beds or veins. 
