Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/200

172 F³. Another double synclinal roll separated by a small anticlinal occurs along the Franklin township line, deep enough to contain small areas of the Lower Helderberg limestone as already mentioned in the description of Franklin township; while a third synclinal, possibly coincident with that of Benfer ridge, creates a loop and a high knob in the limestone ridge northeast of Beavertown, high enough to preserve on its summit a strip of the Oriskany sandstone nearly ½ a mile in length, between which and the main Oriskany ridge further north there is a narrow anticlinal which can be traced from Grimm’s mill on the Franklin township line to and beyond a gap of Mill branch north of Beavertown.

The rock series contained in this township extends from the Oneida sandstone and conglomerate, here elevated in a high central ridge of Shade mountain, to a strip of Marcellus and Hamilton slates nearly a mile wide along the northern side of the township.

The Oneida and Medina rocks of No. IV show no good exposures, for none of the mountain streams are sufficiently long or strong enough to cut into these hard mountain rocks; but the flat dip of the rocks in this part of the range, not averaging over 30°, has created a distinctly double ridge of Oneida No. IVa, and Medinia No. IVc, ½ a mile apart and separated by an elevated valley of Medina red sandstone and shale, IVb.

The Clinton rocks occupy the north flank of the outer Medina ridge and spread through a belt of country nearly a mile wide, at the northern end of which the Ore sandstone ridge makes a prominent break in the topography.

At Shipton run, which cuts through this ridge a mile west of the Franklin line, the Sand Vein ore bed is small and the hill low, affording very little breast; but south of Beavertown, and for some distance east and west of that point this ore-bed contains from 20″-26″ of good soft fossil ore, which has been opened in fifty places by small cross cuts driven through the overlying shales which dip about 20° towards the northwest.

In the ravine however, the Sand Vein is largely a hard