AGS Information Circular 40 is a technical report that focuses on the exploration potential of the Fayetteville and Chattanooga Shale reservoirs in the western-central portion of Arkansas. The study area for this report lies west of the current exploration and development of the Fayetteville Shale resource and thus represents a region that may contain additional shale-gas reserves. Information Circular 40 specifically examines the details of petroleum geochemistry and thermal maturation of the Fayetteville and Chattanooga Shale reservoirs and integrates that information into subsurface geologic models. This report is scientific in character and the primary audience for the report is industry and academic professionals that have a background in petroleum geology.