STRATIGRAPHY AND STRUCTURE CASTLETON AREA VERMONT

the Taconic Range, which separates the Vermont Valley on the east
from the Hudson lowland on the west (Fig. 1).
Most of the eastern third of the Castleton quadrangle lies in the
Vermont Valley; the central third is occupied by the higher hills of the
Taconic Range; the western third is in the slate belt, an area of Taconic
foothills that decline in elevation westward to the Hudson Valley. The
highest point in the Castleton quadrangle is Herrick Mountain (2727
feet) at the crest of the Taconic Range. In the Castleton area over a
dozen Taconic hills are more than 2000 feet in altitude. The lowest point
is 360 feet where the Otter Creek flows northward across the northern
end of the quadrangle. The maximum relief is approximately 2350 feet.
The Vermont Valley in the latitude of Rutland extends about two
miles east of the city, but north of Rutland the Green Mountains swing
westward into the northeast corner of the Castleton quadrangle. The
valley is interrupted by Pine Hill and Boardman Hill and by the ridge
between West Rutland and the Otter Creek. Consequently the compound
Vermont Valley in this vicinity includes the West Rutland-
Clarendon Springs valley, the Center Rutland-Proctor valley, and the
Rutland valley—all trending north. These valleys are developed on the
limestones and dolomites.
Relief within the Vermont Valley is about 1000 feet. Relief in the
slate belt averages 500 feet. Oval, north-trending hills are characteristic
of the slate belt, and several lakes occupy the western part. Lakes
Bomoseen and St. Catherine (Pawlet quadrangle) fill shallow troughs
that may have been stream valleys overdeepened by continental glaciation.
Drainage
The streams of this area belong to two systems: those ultimately
draining into the Castleton and Poultney rivers, which flow west to
empty into Lake Champlain at Whitehall, New York; and the tributaries
of the Otter Creek, which flows north to reach Lake Champlain at
Ferrisburg, Vermont. In the southern part of the quadrangle the Poultney
River receives the drainage of the west flank of the Taconic Range,
and the Otter Creek, by the agency of the Clarendon River, gets the
drainage of the east flank of the Range. In the northern half of the
quadrangle both sides of the Range drain westward through the Castleton
River valley, which completely breaches the mountains west of
West Rutland.
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