
Report of Progress is a series of reports published by the Geological Survey of Pennsylvania in the late 19th century. Intended to provide detailed information about the geology of the state, the reports cover everything from rock formations to mineral resources to topographical...

Report of Progress is a series of reports published by the Geological Survey of Pennsylvania in the late 19th century. Intended to provide detailed information about the geology of the state, the reports cover everything from rock formations to mineral resources to topographical...