Now that I think about it, when I was in college in Blacksburg, VA, I visited an old defunct coal mine some miles from town. In addition to getting some beautiful old rough-cut white oak lumber from collapsed buildings, I grabbed a pile of coal to use in our stove, our only means of heat. It didn't burn at all, as I could tell. It was dead-black shale or something that looked just like coal. No wonder the mine shut down. I'm sure that would have made a perfect candidate for "Keystone black". That stuff is all over the place up and down the east coast. I've seen mountains of it around Hazleton, PA, which is not far from Muncy.