in the vicinity of Great Barrington, Mass. 89 
The dip of the limestone in this section is mostly between 
45° and 55°; the mean strike is N. 10° E dip of the 
schist is, with small exceptions, 35° to 40°, and the strike N. 
10° to 20° E. There is a wrench in the ridge south of the 
highest part (z on the map), so that the strike varies; being 
N. 10° to 20° W., at points northeast of 2; N. to N. 10° E.,, 
to the east of it, or at the marble quarry; then, N. 25° E., 
and finally N. 40° to 50° E., 150 yards to the east of south; 
and this last strike is found across this part of the ridge at the 
western foot. 
_ The evidence of the existence of a bed of quartzite in the 
ridge is small but positive. Hard-jointed quartzite outcrops at 
a point toward the upper limit of the schist, S. E. of z, for a dis- 
tance of 12 or 15 yards, and also at a second point above, both 
of them west of the village. The strike of the outcrop is N. 
50° K., conforming to that of the limestone above it, its position 
being in the wrenched portion of the ridge. The thickness of 
the bed may not be more than fifteen yards, as the outcrop 1s 
no wider; but the shortness of the outcrop in the line of the 
bedding is proof that the bed is mainly the soft quartzite; and 
if so, it may be 100 feet or more in breadth. Three-quarters of 
a mile to the north, along by y, near a road crossing the ridge, 
the surface of the fields is thickly strewn with great blocks of 
quartzite, which seem to indicate that the bed exists beneath, 
and has considerable width. This range of quartzite masses 
continues near the road to the eastern of the spurs of quartz- 
ite, at the south end of Tom Ball ridge; and at « there is a 
low hill of outcropping quartzite. These facts connect the 
rocks of the Tom Ball and ong Pond region with those of the 
ridge just west of Great Barrington, giving positive proof that 
the quartzite is the lower quartzite, or q’. 
The ridge west of Great Barrington consists, consequently, 
above the underlying limestone, of (1) a lower stratum of schist 
(s'); (2) a bed of quartzite (q'); (8) an upper bed of schist (s?) 
much thicker than the lower (s') There is no upper quartzite. 
_ This section introduces a new element, an upper stratum of 
limestone, overlying the upper schist (s*), where the upper 
uartzite would be looked for. It outerops in the valley near 
the railroad and also east of the river and village. The lime- 
Stone is a bluish-gray and firm granular variety. Some por- 
tons are quite pyritiferous; and at one spot (near the Maple 
avenue crossing) {found minute brown tourmalines with the 
pyrite, Just west of the railroad track, 60 yards north of the 
aple avenue crossing, the limestone outcrops within fifteen 
yards of the schist, and both have the strike N. 7° to 10 E., 
and eastward dip 65°. There is another outcrop at the Maple 
avenue crossing, giving the strike N. 8° E. and dip 40° to 35°. 
