January 11, 2008
One of the most impressive geological formations in the eastern United States, the Whaleback Anticline near Shamokin, Pennsylvania, is a superb natural laboratory for geologists and geology students studying the dynamic forces that shaped the planet. Located in the Middle Anthracite region, this former strip mine displays faults, folds, joints, and cleavages. Resembling the scarred back of a giant sperm whale, this folded rock or anticline has steep sides and a rounded, narrow crest on its spine. To its left, a syncline with a black vein of anthracite coal is visible. Plant fossils are common in the shales here, and unique ironstone concretions, some up to a meter in diameter, resemble giant warts on the dark gray rock. Pennsylvania has declared this locale a Heritage Geology site.