Abstract Across much of the Gulf Coast basin of the USA, the Smackover Formation consists of a nearly 100 m-thick shoaling upward cycle capped by oolitic/oncolitic packstones and grain-stones. It has long been interpreted as a homoclinal ramp succession, which was analogous to the modern example in the southeastern Arabian Gulf. In a three-dimensional seismic survey in north Louisiana, the shoaling-upward cycle is imaged as basinward progradational clinoforms (4–7° inclination) with well-defined toplap and downlap surfaces. In map view, amplitude slices show that the clinoform bodies are strike-oriented and continuous. The inclination and width of the clinoform bodies indicate that water depths of up to 90 m were present within 1 km of the shoreline. Such characteristics indicate that the Smackover Formation cannot be classified as a homoclinal ramp in north Louisiana and that the Arabian Gulf is not analogous to the Smackover.