The Carboniferous Periods (Pennsylvanian and Mississippian) formations in the center of the Midland Basin are an average depth of ~ 11,000’ below surface. Most of the coal beds are located in the Atoka Formation (Pennsylvanian). During the time of deposition, occasionally we see evidence of huge fires. The evidence is in the form of a light tan colored sediment known as “fire clays”. These sediments tend to be associated with coal beds that apparently caught on fire.

In the Midland Basin, these coal beds are generally very thin thickness < 1’