258 J. D. Dana on the Quartzite, Limestone, etc., 
synclinal; instead, the 
ined be 
slope continues on and terminates in a 
fault, as explain Gut 
hi 
ond. 
ile this is the position of the rocks in this Monument 
Mountain section, there are, but a mile north of the position of 
the mountain—as shown in the Glendale section—two steep 
and small synclinals (V1, V*, fig. 9) of the same schist and 
9. 
Section from Glendale westward. 
limestone, with intervening anticlinals, the limestone being the 
prevailing and ae ene rock, between whose jaws the schist 
was pinched up; and, further, these two small synclinals nar- 
row out within a mile to the south against Monument Mt.t— 
each trough where widest being too narrow to take in much of 
the overlying schist, and including less and less as it extends 
southward. 
Now in the section through Great Barrington,—three miles 
south of the east end of Monument Mountain and four miles 
of the west end (and separated from it by open meadow land) 
—the position of the rocks is still different ; and the rocks them- 
selves, although equivalents, are also to some extent different. 
There is a fault, as in the Monument Mountain section ; but 
instead of a fault at the east end of the section, it is near the 
Housatonic River toward the west end (see fig. 10), and east of 
the fault there extends for three miles a single low synclinal of 
gneiss, with overlying quartzite at the west end and underlying 
quartzite at the east: and at the east end there is next—instea 
of a fault—the beginning of a low anticlinal, whose middle 
oe is occupied by the southern continuation of Muddy Brook 
alley, and whose eastern side is a bluff of quartzite overlaid 
by gneiss, and underlaid by alternations of limestone, gneiss oF 
mica schist and quartzite. 
_ The following are the details with regard to this Great Bar- 
rington section. 
In my last paper on this subject, in volume v, of this J ournal, 
I give, on page 88 and beyond, some account of the section west 
of Great Barrington, continued eastward through the village to 
the mountain (Hast Mountain) bounding the valley on the east, 
and illustrate it by the following cut (fig. 10). Here the low 
portion is the position of Great Barrington village, underlaid 
* Page 265. The rocks of Monument Mountain owe their preservation as ® 
Pe hie J to a ee to the cap of hard upper quartzite. 
b 
