Geology and Mineralogy of apart of Massachusetts, &c, 7 
where the strata were nearly perpendicular, and easily divi- 
ded into narrow tables, from four to twelve inches thick, and 
many feet in length. The line of the grain of this stone is 
inclined to the horizon about 30°, and dips towards the 
north, so that while itis in the nearly perpendicular plane 
of the strata, it is oblique to the horizon and the general lev- 
el of the strata. The mica-slate may often be split in this 
manner; but a great portion of it is destitute of any grain. 
In the town of Windsor, Mr. Hitchcock observed a rock, 
which seems to be conglomerated mica-slate. The same 
kind of mica-slate is often to be found along the middle of 
Berkshire Co. towards the foot of the eastern range of 
hills, and along the east side of Taconick range. The 
quartz occurs in it in considerable masses, besides the 
portion which seems to enter strictly into the composition of 
this kind of slate. 
Various minerals are contained in this rock. Along the 
eastern part of the section, it contains vast quantities of 
garnets, generally small, sometimes an inch on the linear 
edges. Also, staurotide, cyanite, schorl; the staurotide 
being in large crystals and very abundant in Worthington. 
In the south part of Berkshire, in Great Barrington and 
Sheffield, the mica-slate is so filled with garnets as_ to look 
at a little distance like the most beautiful puddingstone. 
One mile east of the meeting house in Sheffield, this rock 
may be found extending miles to the north; a similar rock 
may be found composing a small insulated hill about a mile 
S. W. of the meeting house, where the road crosses its 
southern base. This rock, with its beautiful garnets and 
staurotide, occurs again, in abundance, nearly south from 
this plane, in Salisbury, Con. There is a very great re- 
semblance between the mica-slate containing these imbed- 
ded minerals, as it is found on the east and west side of the 
eastern range of mountains, though separated by an inter- 
posed stratum of limestone, anda stratum of mica-slate desti- 
tute of these minerals. On the east side, however, as at 
Chester, Middlefield, &c. the mica-slate also contains chlo- 
rite, crystals of calcareous spar, stilbite, chabasie, cyanite 
&c. neither of which have I ever found in the mica-slate on 
the west side of the range, although garnet and staurotide 
are so abundant in it. 
