Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/217

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20.West Beaver Township in Snyder.

F³. 189

and on the divide between the waters of the Susquehanna and Juniata. Bannerville is a smaller village about 2 miles northwest of McClure in the Devonian slates of the North- umberland synelinal basin.

The drainage of the township is entirely eastward through numerous small branches of Middle creek, which rise in this township.

The struclure of the township is largely the same as that of Spring, with the exception of the absence here of the ore synclinal basin which rises rapidly from Adamsburg and expires before reaching the West Beaver line, so that in this township the main ore ridge approaches much closer to the mountain with the effect of stiffening the dip.

The rock series extends upwards from the No. II] Hudson _ river slate to the Devonian measures No, VIII, the former being exposed upon the crests of both the Jack’s mountain anticlinals, and the latter in the trongh of the Northum- berland synelinal, which passes almost directly through the center of the township.

The Medina sandstone is poorly exposed in the gaps of two small streams cutting the sonth flank of Jack’s mount- ain north of Bannerville, the white Medina being by esti- mation about 500’ thick here. These same rocks are not exposed at all in the sonthern portion of the township, which is equally true of the underlying Oneida sandstone. Great quantities of bowlders, however, show everywhere.

The Ore sandstone was seen in Ulsh’s gap about one- fourth of a mile above the old mill, on the Jack’s mountain outcrop, with a dip of 8, 25°, EF. 40° ; but neither the Sand Vein nor Danville fossil-ore beds have been uncovered here. The Bloomsburg red shale outcrops west of Krepp’s gap on this side of the valley with a dip of 40° 8. E., but its ont- crop is largely concealed by the immense amount of débris brought down from Jack’s mountain through these two gaps. On the south side of the valley these rocks make a distinct red band everywhere south of the railroad, made prominent by contrast with the gray lime soil of the upper Salina creating the valley throngh which the railroad runs.

The Lower Helderberg limestone was once opened on its