Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/85

Rh alone all through the Juniata district. The position of this series is shown on the map by a deep blue tint.

In Union county the rocks of formation VI outcrop through Gregg township, where the beds are thin, and are nowhere opened over 50′ in thickness.

The Lower Helderberg limestones are next seen in the Buffalo Valley synclinal at Lewisburg, making the boat-shaped “Limestone ridge,” in which several quarries have been opened. Here, and along the Mifflinburg limestone ridge, the lower massive “Bossardville” beds of the group have been opened, without exhibiting any complete section. This division, however, with its usual shale partings, is fully 80′ thick and yields an excellent quality of limestone. The upper lime shales are about 110′ thick, and are very fossiliferous, but nowhere quarried.

The Winfield quarries, in the extreme southeast corner of the county, belonging to the Union Furnace Company, perhaps exhibited the best section of the lower Bossardville beds, as they have been more extensively quarried here than elsewhere, both for furnace flux and the general market.

The series can be conveniently divided into two divisions, an upper (immediately under the shaly beds) 50′-55′ thick and furnishing some good beds; and a lower, 48′ thick, holding several massive beds, and yielding both fine grade paper-lime and furnace flux. A bed, 6′ thick, of shelly porous rock, very hard and lean, divides the two groups; the whole forming a series practically 100′ thick.

In Snyder county a double outcrop of limestone flanks the Northumberland synclinal, following the line of the Oriskany sandstone already described, and often replacing that rock as the crest of the ridge.

The Winfield beds are opened on the north side of the basin in many places as far west as New Berlin; but not as completely as on the river. There is another group of quarries in Kline’s ridge, along the same belt as Troxelville; but they are small and show no better sequence of