Dr. Terry Engelder, Professor of Geology at Penn State University, right, uses an outreach guide while explaining the Marcellus Shale formation to former Pennsylvania Governor Tom Ridge during a tour ... more 
Dr. Terry Engelder, Professor of Geology at Penn State University, right, uses an outreach guide while explaining the Marcellus Shale formation to former Pennsylvania Governor Tom Ridge during a tour of outcroppings near Williamsport, Pa. on Thursday, June 16, 2011. (AP Photo/Ralph Wilson) less 
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Associated Press | Photo By Ralph Wilson
Mon, Jun 27, 2011 2:53 AM EDT