Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/126

98 F³. railroad, show but comparatively few dips to indicate the structure minutely.

The Montour anticlinal axis of Northumberland county, passing through the high and prominent Montour ridge, reaches the Susquehanna river in East Buffalo township about 1½ miles below Lewisburg; but its strength has become so reduced that its presence is only detected by the zigzag outcrop of the Bloomsburg red shales, whose low dips at that point make a broad double belt of red soil between Lewisburg and Turtle creek.

The Jack’s mountain anticlinal, which marks the crest of Shamokin mountain in Kast Buffalo township, likewise expires along the river about 2 miles south of the Montour anticlinal, these two axes strengthening and rising in elevation and importance in opposite directions. The Medina white sandstone occupies the crest of the Shamokin mountain for about 1¾ miles in East Buffalo township, sinking eastward beneath the Clinton rocks, while the axis in approaching the river becomes dimpled and carries a narrow synclinal roll of the Ore sandstone and fossil ore for perhaps a mile west of Turtleville.

The Mifflinburg synclinal occupies the valley of Turtle creek between the Montour and Jack’s mountain axes. It deepens going westward from the river, so that from first holding only the upper Clinton and lower Salina rocks in its trough, it sinks along Turtle creek to receive the upper Salina in a broad basin, 5 miles in length, and along the Limestone township line the next higher (Lower Helderberg) limestone rocks.

The geological section of rocks exposed in these two townships extends from the Medina sandstone of Shamokin and Buffalo mountains upwards to the No. VIII Marcellus black slates occupying a narrow strip in the Lewisburg synclinal along the south bank of Buffalo creek.

The Ore sandstone and Sand Vein fossil ore bed show but a single outcrop in the north end of Buffalo township, creating a low ridge about three miles in length, between