The Marcellus Shale is a naturally-fractured gas shale, and the body of literature on the characteristics ofthose fractures is expected to grow significantly as additional data are gathered. In some respects, the only
way to gather additional data is to drill more wells and examine rock carefully removed from the well (a
process called core sampling), so some things could remain unknown until after additional drilling has taken place. While this pamphlet highlights much of the base level understanding of Marcellus Shale jointing, some generalizations will be refined only after engineers have collected and analyzed data from numerous wells and core samples throughout the Marcellus.