Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/161

Rh west, where they are scarcely a mile apart. Its area will fall short of ten square miles.

Winfield on the river and the Shamokin and Sunbury division of the Philadelphia and Reading R. R. is the only village in the township; but it is noted as being the seat of one of the most successful and best managed iron plants in this part of the state, which has been largely responsible for the development of the ore beds of Union and Snyder counties for many years.

The geological section of rocks exposed in this township extends from the Medina sandstone No. IVc on the crest of Shamokin mountain up to the Chemung division of No. VIII in the high ridge along the Snyder county line.

The structure of the township is very simple, as it lies entirely on the south side of the great Jack’s mountain anticlinal, all its rocks dipping comfortably towards the southeast into the Northumberland synclinal.

It has already been stated how the eastern end of the Jack’s mountain axis is dimpled along the river, carrying a close synclinal fold and an ore basin for about a mile west of Turtleville.

On the south side of the main anticlinal, the ore beds are comparatively thin, except at the eastern extremity; still a large quantity of ore has been mined at various times from different openings in the Danville ore beds and used at the Union furnace at Winfield. The Sand Vein ore bed does not seem to exist in this portion of the range at all until after passing west of Centerville on Penns creek; and the Ore sandstone itself is generally shaly and porous, breaking up readily and therefore largely eroded.

The underlying Clinton shales show with flat dips along the flank of Shamokin mountain; but the Iron sandstone and Bird’s Eye fossil ore germane to this portion of the formation seem to be as conspicuously absent or as hard to recognize as the higher Ore sandstone group.

The lowest Danville ore bed developed a thickness varying from 20″ to over 3′, where first opened at the eastern end of the ridge, and according to Dr. Rook, manager of the Union furnace, it maintained that thickness for about