Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/167

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This is an irregular-shaped township, occupying the extreme northeastern corner of Snyder county between the Susquehanna river and Penns creek. Its southern border line along the public road dividing it from Union county is about 6 miles long; but it narrows southward to a point at the junction of the creek and the river above Selinsgrove. Its area is about 20 square miles.

The drainage is all southward, either by small tributary streams without names, directly into the Susquehanna river, or by Penns creek and its branches.

The rock section exposed within its borders is extremely limited, owing to the structural features of the township, which comprises the deep Northumberland synclinal basin crossing the river at that town and reaching Penns creek about 4 miles above its mouth, opposite Kratzerville.

The Catskill sandstone and slate fills the trough of this basin from east to west. Its red rocks, which here have been taken to limit the formation, occupy a belt nearly 2 miles wide through the center of the township, flanked on either side by the No. VIII slates and sandstones. The entire series of this latter formation is exposed in the south leg of the synclinal on dips of from 10° northward along the belt of Oriskany sandstone in the southern corner of the township to 60° at the margin of the Catskill No. IX rocks.

The Lower Helderberg limestone No. VI occupy the extreme southern corner of the township south of the Oriskany sandstone belt on very low dips in obedience to the broad flat arch of the Selinsgrove or Shade mountain anticlinal axis. No exposures of these latter rocks are seen within the limits of this township, partly owing to the flat dips