394 W. M. Davis—Nonconformity at Rondout. 
den in passing through the town. Crossing the creek, they 
build the limestone outlier, a flat synclinal with steep or ver- 
tical dips on the eastern side, and then cross the stream again 
by the railroad bridge and plunge underground at a high angle. 
The anticlinal half of this S-shaped curve is not a simple turn, 
but is complicated by a small additional fold where the stream 
erosses Section III, as is shown on a larger scale in figure 2. 
Fig. 2. 
From here, up the valley, the strike is very uniform, and the 
bluff-front very even. Sections carried across it at several 
points showed a well-marked synclinal stracture bounded on 
the northwest by a down-fault of moderate throw. In con- 
formity with what seems to be “ normal” for the Appalachians 
this fault is drawn with the upthrow overlying the hade. Dy 
following along the axis of this synclinal from Wilbur, one 
asses over seven different subdivisions of the Upper Silurian 
that successively come to an end in the rising trough. 
This detailed statement of the altitude of the rocks seems 
necessary in order to contradict the supposition not unfrequently 
made some years ago that a “great fracture” passed along the 
Hudson valley between the older and newer rocks. Apart from 
the folds ane local faults of small throw there is no evidence 
whatever of any great disturbance, and the great fracture 1S 
purely hypothetical. The Oneida and Medina lose the moun- 
and farther on, the arch (or fault) which forms the western-side 
of the synclinal, disappears, and the Corniferous and Marcellus 
otal is continued as a Marcellus monoclinal valley, occupied 
by the Kaaterskill on its northward course and crossed by the 
Catskill at Leeds.* _ 
Glacial strise were observed at several places with a direction 
*See papers by the author in Appalachia, iii, 1882, 20; and Bull, Museum 
Comp. Zool., Geol. Series, i, 1883, 328. Pek 
