Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/330

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
302 F³.
E. V. d’Invilliers, 1889.

long, beyond which in each direction the flexure rises rapidly in the Lewistown and upper Salina rocks. In the valley between this ridge and the river there is a pronounced but equally short anticlinal, which carries a narrow wedge of the upper Salina rocks up to within a half mile of the forks of the road at the school house. West beyond this only the Lewistown limestone is exposed and, as the axis subsides quite as rapidly as it rose, these limestones, as well as the very thin band of Oriskany sandstone overlying them, are carried down beneath the Marcellus slates before reaching the Juniata south of Newton Hamilton.

The public road at the school house is about on the crest of this anticlinal. The limestone and the sandstones Nos. VI and VII dip between 70° and 60° to the northwest along the river. In the low gap at Jenkin’s house through which the road runs 1 mile east of the school house a good series of the limestone measures is exposed but very thin bedded nearly 100′ thick. The Oriskany sandstone measures seem to be totally eroded along the north flank of this anticlinal at least as far as their topographical influence is seen along the river. The Juniata river flows for nearly 2 miles across the steeply upturned edges of the Lewistown limestone formation, a portion of which is seen on either side of the river east and west of Vineyard station, finally issuing on the east bank of the river near the Oliver township line and making the supporting flank of the Enterprise Mine synclinal as already explained.

Several small quarries have been opened in this belt, but none of them show very extensive sections of the rock. Passing under the Enterprise mine synclinal these limestones are again brought up on the back of the Chestnut Ridge anticlinal, next north, and continue to be exposed in a high ridge for about 1½ miles west of the Oliver township line. There they sink beneath the wide rolling plateau of Oriskany sandstone which makes such a prominent and remarkable exposition of this formation in the central part of Wayne township.

Vineyard. One small limestone quarry has been opened on the Vineyard property, well up the flank of the ridge