Pittsburgh Post-Gazette: The Marcellus Shale preceded the founding of Pittsburgh by a good 350 million years. The rock layer laid safely tucked a mile underground until in the early 2000s, when the shale gas -- through a combination of horizontal drilling and hydraulic fracturing -- began its ascent to stardom. Now it all but defines the region.
Pennsylvania has been an oil and gas producing state since the late 1800s. Thirty years ago, gas wells in Pennsylvania pumped out a respectable 118 billion cubic feet of gas in...