5. How was Pennsylvania significant in the production of fossil fuels?

Pennsylvania was the third-largest coal-producing state in the nation , and it was the second-largest coal exporter to foreign markets.

Pennsylvania, endowed with extensive fossil energy resources, is a leading East Coast supplier of coal, natural gas, electricity, and refined petroleum products to its own industries and to the nation.

The Appalachian Mountains in the state hold rich coal resources and run diagonally southwest to northeast through Pennsylvania, dividing the Ohio River valley in the west from the Susquehanna and Delaware River valleys in the east.

 The Marcellus Shale, the largest U.S. natural gas field, follows the arc of the mountains and underlies about three-fifths of the state.

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