The town of Haynesville is the namesake of the Haynesville Shale, an upper Jurassic formation that is difficult to define on a technical basis but nevertheless covers a broad region of western Louisiana and east Texas and contains a large natural gas resource. On March 24, 2008, Chesapeake Energy announced a new natural gas discovery in the Haynesville Shale. This announcement began a new chapter in the development of the Hayneville Shale and hastened the activities of several other companies in the play.