Photo Gallery

 Long periods of weathering and erosion created these "opferkessels" at Beam Rocks, Forbes State Forest, Somerset County.
 Ledges of Devonian sandstone overlook Adams Falls, Ricketts Glen State Park, Luzerne County.
 Mega-ripple marks cover the surface of these near-vertical beds of Antietam quartzite in Guilford Township, Franklin County.
 A group of teachers are collecting from the fossiliferous Mahantango Formation in Monroe County.
 Limestone was burned to produce "quicklime" in these kilns at Canoe Creek State Park, Blair County. Limestone quarry in Chester County. Limestone and dolomite have helped make Pennsylvania a national leader in aggregate production.
 The "Whaleback" anticline in Bear Valley strip mine near Shamokin, Pa is a natural laboratory for teaching structural geology.
 Kinzua Dam near Warren impounds the Allegheny Reservoir. Knowledge of site geology is critical in choosing safe locations for dams. Pump jack on an oil well in the Allegheny National Forest, northwest Pennsylvania.
 Tightly looping meanders of Conodoguinet Creek in eastern Cumberland County.
 Interference ripples, or "tadpole nests," Rose Hill Shale (Clinton Group) near Danville, Montour County. Slumped Homewood sandstone boulders resulting from glacial lake drainage through the Slippery Rock Gorge, Lawrence County.