TYLER HILL, Pa. -- Marian and Ed Schweighofer know right where they want their gas well to be drilled. It's a flat spot on top of a knoll, out of view of their two-story home, where hay now grows. But they do not know when it will be drilled, or if it will be. The Marcellus Shale drilling that has raced across Pennsylvania for the past five years has stopped short of the dairy farms and hay fields here in the Poconos foothills. That is because the Delaware River Basin Commission, an obscure-but-potent federal agency, has stopped the gas rush in its tracks in northeastern Pennsylvania's Wayne and Pike counties.