Chesterian Series

The Chesterian Series is the uppermost major stratigraphic division of North American rocks of the Mississippian. Exposures of Chesterian rocks occur in the Mississippi Valley region, where they consist of about 458 meters (1,500 feet) of alternating limestones, sandstones, and shales. The lowest unit of the series is a sandstone, which is succeeded by cyclically recurring sandstones and limestones. The sandstones contain economically important petroleum reserves, and extensive drilling has provided detailed information about the shapes of the deposits. Many of the sandstones are thought to represent channel fillings of Mississippian stream systems.