Whaleback, Northumberland County


Location: Bear Valley strip mine, near Shamokin, Northumberland County, Shamokin 7.5-minute quadrangle; approximately 40º 46' latitude and 76º 35' longitude.

Size: The whaleback area covers about 7 acres.

Whaleback in Northumberland County

Geology: Arguably one of the best exposures of folded rock structure in the United States. In this small area, all the structural elements and (6) stages of deformation for the Valley and Ridge Province can seen and studied. It is considered the type locality for examining the style, mechanics, and stages of structural development for the rocks in the Appalachian folded mountain belt. Individual structural elements such as faults (3 types), folds, joints, cleavage, lineations, and slickenlines can be examined in a hands on setting. Visually engaging because of the size and preservation of the folds.

Heritage value: Site is scientific, educational, scenic, and historical.

Heritage status: Because site is privately owned, heritage status is in the hands of the owner.

How to Access: This site is located on private property.

References: Nickelsen, R.P., 1979, Sequence of structural stages of the Alleghany orogeny, Bear Valley strip mine, Shamokin, Pa.: American Journal of Science, v. 279, p. 225-271.

Edmunds, W.E. and Eggleston, J.R., 1984, Field Guide to the Pennsylvania Anthracite Region.

For information regarding geologic features and PNHP, contact Jim Shaulis of the Pennsylvania Geological Survey at 717–702–2037.