"Ninety miles north of Philadelphia, layers of anthracite coal undulate underground, pushed into steep folds by tectonic action. These are the Coal Measures of the Anthracite Coal Fields of Pennsylvania. They formed 300 to 320 million years ago, and gave their name to the Pennsylvanian epoch in the geologic time scale."
This, and more, on view in our exhibition Seeing Coal.
Samuel H. Daddow and Benjamin Bannan. Coal, Iron, and Oil; or, the Practical American Miner (Pottsville, 1866).













