Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/291

Rh There are no villages of any importance in this township, though its ores, rocks and farm products make it one of the richest townships in the Juniata valley.

Structurally it is as much broken up as Derry township to the east of it; and yet, bearing in mind the key to the structure already explained there, the confused mass of ridge and valley land in the center of the township will reduce itself to perfect order and simplicity.

Between the Lewistown valley and the Ferguson valley there are 3 synclinal ridges, containing Oriskany sandstone No. VII, and a small thickness of the Marcellus slates No. VIII in narrow valleys eroded between the several ridges.

The rock series of the township is comprised between the Medina rocks No. IVb and c in the two bounding mountains, and the bottom layers of No. VIII.

Just northwest of Lewistown the first Oriskany ridge is split along the center for nearly two miles and contains therein a slate valley of Marcellus rocks; but this little valley narrows rapidly until the two opposing walls of the ridge come together and furnish the magnificent section of grass sand-rocks quarried by the Juniata Sand Company about 4 miles west of Lewistown. A little anticlinal flexure north of their quarries serves to spread the outcrop of this sand-rock over a broad plateau 350 to 400 yards wide. The final dip on the north side of this ridge is to the northwest, the sand-rock passing down beneath a second Marcellus slate valley, which begins at the Derry township line north of Lewistown and extends southwestward as a narrow strip coincident with the Ross Ore Bank synclinal north of McVeytown.

This narrow valley is best known under the name of “Squaw Hollow,” in this township and as “Dry Hollow” further west.

The succeeding anticlinal north of this basin carries the upper Salina lime shales on its crest for three miles west of the Derry township line and beyond that it is an arch of the Lewistown limestone to the Oliver township line. In this latter township it again increases in strength sufficient to bring up the Salina measures, so that at a point some-