Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/343

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
35. Monroe. 36. Greenwood. 37. Susquehanna.
F³. 315

accuracy, is seen along the west branch of Mahantango creek from Richfield to McKee’s Half Falls.

The Marcellus slate is exposed just south of the gap in Flintstone ridge upon a 40° southeast dip. The Hamilton sandstone succeeds on a dip of 25°, making a high ridge at Shellenberger’s Mill at Stony Point. Below the mill the Hamilton upper shales are exposed, brown in color and dipping about 20° to the southeast near the first road passing into Snyder county. Just below the second grist mill there is another exposure of hard gray sandstone probably associated with the Hamilton division, and really creates but one ridge with the more northern outcrop. Going up the ridge road from here south to Peatown, brown and black shales largely predominate with a southeast dip of about 45°; but interstratified with some few sandstone beds. The exposures are few and unsatisfactory.

Along Quaker run, near the first saw mill east of Peatown, a still higher series of gray shales is exposed on a southeast dip of 30°, and along this road for the first time are seen bowlders of Chemung conglomerate with white rounded pebbles evidently derived from the crest of the ridge south of the stream. East from this mill the creek cannot be far off the line of the synclinal, for between the school house and the forks of the road the gray and brown shales do not dip over 5° southward.

The conglomerate bowlders become more profuse going down Quaker run from the school house. They are brown and gray in color, often iron stained, but occasionally holding large pieces of white quartz. An exposure of reddish brown slates within one-half mile of Mahantango creek still dipped 20° to the southeast; but at the next cross roads below Jones’ house the same reddish slates and thin sandstone dip N. 20° W. 45°.

In Susquehanna township, on the road west of Shaffer’s old saw-mill, on Mahantango creek, there is an outcrop of sandstone dipping northwest 20°, and just south of this point the road to Oriental exhibits the presence of a small anticlinal in gray shales and thin sandstone, first dipping about 40° towards the southeast and increasing southwards