Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/396

368 F³. The Spruce Hill-Tuscarora township line is a straight one, 3½ miles long between Tuscarora creek and Tuscarora mountain; while the mutual line between Spruce Hill and Turbett townships is a somewhat irregular one, running between the creek and the mountain in a general north and south direction from a point 3½ miles west of Port Royal, south between the two forks of the mountain road leading over into Perry county.

Spruce Hill is slightly the larger of the two townships, whose combined area may be estimated at about 40 square miles.

The drainage of both townships is all northward from the mountain into Tuscarora creek, except a small portion of eastern Turbett township which drains eastward directly into the Juniata river. All these streams are insignificant except Tuscarora creek, which flows in all directions of the compass, and makes a remarkable horseshoe bend, nearly 3 miles long east of Pleasant View, cutting through at two places in each of the limestone ridges bounding the Tuscarora slate valley, and on the south cutting nearly one-half mile into the Salina rocks of Spruce Hill township. In this great bend the creek on either side is never more than a mile distant and in places it approaches itself to within half that distance. (Compare the great bend of the Juniata below Mount Union in Mifflin county.)

The geological rock section extends from the red Medina sandstone and slate No. IVb in the Tuscarora mountain upward to the Marcellus slate and lower Hamilton shale in the basin of the synclinal along the Tuscarora township line. The No. IV rocks in Tuscarora mountain are nowhere well exposed in place, as with the single exception of a small gap in the north white Medina crest along the Spruce Hill-Turbett line, the mountain is entirely unbroken.

But one road crosses it into Perry county between the Juniata river on the east and its western extremity in Tusarora township south of Bealetown, and this road passes completely over the summit. Just before reaching the last bend of the road north of the summit a poor exposure of the red Medina rock dips nearly due N. (25°,) creating the