The Ramp Creek, Harrodsburg, Salem, St. Louis and Ste. Genevieve formations include a wide variety of carbonates, including silty dolomudstones, mudstones, wackestones and skeletal and oolitic grainstones. Analysis of these Middle Mississippian carbonates from surface exposures and cores indicates that small- and larger scale depositional cyclicity is prominently developed. Four facies representing four major depositional environments are recognized: A) calcareous sand and oolite shoals and bars, B) tidal channels, C) lagoons and D) sabkhas. Although characteristic trace-fossil assemblages occur within the various facies, recognition of trace fossils is controlled largely by preservational factors such as degree of lithologic heterogeneity and mean grain size and degree of weathering in surface exposures.--Modified journal abstract.