VERMONT. 97 
another one. There appear, therefore, to be two masses of Mack beds and three of 
roofing slate. Mr. Prindle finds some evidence of an Ordovician area at the top of 
the hill. It would seem, therefore, possible that between thai point and the red slate 
of the valley on the east we have an anticline consisting of several minor folds, and 
that the Cambrian green and purple slate occupy the centers of (he lesser anticlines 
and the black shales the sides, as shown in the section. But the structure might he 
interpreted as consisting of two beds of green and purple slates alternating with two 
of black shale, or a fault could be supposed between the central body of green slate 
and the black slate west of it. Several quarries in this line show about 70 feel of the 
black rock (D). 
Only occasional observations were made in the valley east of the ridge, and these 
all indicate low easterly dips, and so do the observations at Nixon's and Pritchard's 
quarries, with slight indications of a westerly dip at one of the latter. The folds 
are probably all overturned to the west, but their dimensions may vary greatly from 
those shown in this part of the section. The only data as to the Cambrian ridge at 
the east end of the section are easterly dips on both its east and west sides, indicat- 
ing the usual overturn. 
SECTION III. — LAKE BOMOSEEN. 
This crosses Cedar Point and extends to Glen Lake. At Cedar Point, Lake I>oni<>- 
seen Slate Company's quarry, there are 127 feet of purple, overlain by 50 of green, 
and these by 5 to 10 feet of limestone, but all doubled over into a close syncline with 
an axial plane almost, if not quite, horizontal and traversed by a cleavage foliation 
dipping 20° east (see PI. XXIV, V). For that part of the section which lies east of 
the Ordovician strip and west of the bend in the section line the data have been 
taken from the old quarries a mile south (see PI. XXIV, rig. T, and PI. XXII). The 
folds are many and small and overturned to the west. At the West Castleton quar- 
ries, north and south of this section and east of the Ordovician strip, the slates dip 
45° to 50° east, and consist of about 25 feet of purple overlain by 8 feet of green 
slate, and these by 8 feet of limestone, followed by poor slates and quartzite beds. 
The relations of Ordovician and Cambrian are not well exposed. The Cambrian 
slates must either turn steeply to the west or be faulted. At the extreme north end 
of the Ordovician strip Mr. Prindle made out the following relations: The Black 
Cambrian slates (D) and the Ferruginous quartzite (E) occur between the Cambrian 
limestone and roofing slates (B) and the Ordovician graptolite shales. About a half 
mile north of West Castleton the graptolite shales occur 300 feet west of the Cam- 
brian slates with some thin quartzites. 
The structure of the Ordovician strip itself is beautifully shown at a ledge by 
the roadside between West Castleton and (den Lake (see PI. III). The rock is a 
grayish, more or less calcareous shaly or arenaceous slate, banded with black beds 
from a fraction of an inch to 2 inches in width. On the west side of the syncline the 
beds dip very slightly east or are horizontal. Farther east, at the top, the dip is 55° 
W. and still farther 90°. The cleavage throughout is about 35° E. The ledge is 
evidently the center of the syncline and gives the key to the structure of the whole 
ptrip, which is 3^ miles in length, while the fossils leave no doubt as to its age. 
SECTION IV.- — BLISSVILLE. 
This crosses several lines of quarries near Blissville, in Castleton, Vt. There are 
feO quarries hereabouts, including the old Eagle quarry. The northeasterly line of 
buarries shows a minimum of about 50 feet of green and variegated slate (strike 
10° to 15° E., dip 20° to 30° E.) overlain by 20 feetof black slateand shale and thin- 
jedded limestone, followed by a few feet of green slate and a bed of quartzite Hi 1m 
JI2 feet thick, which is exposed for 350 feet along the strike. The quartzite contains 
.'alcareous nodules which weather out and overlies and, at the south, runs into a 
I 
