Geologic map that depicts the surface geology of Borden, Scurry, Fisher, Martin, Howard, Mitchell, and Nolan Counties and parts of Glasscock, Sterling, Coke, Runnels, Taylor, Jones, Dawson, Martin, Lynn, Garza, Kent, and Stonewall Counties.

The Eastern Shelf was a constructional platform developed on the margin of the sediment-starved Midland Basin during Late Pennsylvanian and Early Permian time. A mixed terrigenous-carbonate sedimentary province characterized the shelf during most of its history.