The Marcellus Shale

The Marcellus Formation, also classified as the Marcellus Subgroup of the Hamilton Group, Marcellus Member of the Romney Formation, or simply the Marcellus Shale, is a mapped bedrock unit in eastern North America. It is a sedimentary rock formed from marine deposits. Named for a distinctive outcrop near the village of Marcellus, New York in an 1839 geological survey, it extends throughout much of the Appalachian Basin. The energy development community is drilling deep beneath the Allegheny Plateau to reach its largely untapped natural gas reserves located near the high-demand markets along the East Coast of the United States.