Feature 20 includes three large, interconnected basins in the southwestern quadrant of the Miami Circle. The walls of these basins are very straight and exhibit cut marks. The northernmost basin is roughly rectangular, while the other two basins are oblong. Seven smaller holes occur in the bottom and sides of the larger basins. Excavation of sandy, black midden deposits from within the basins produced a few ceramic sherds, shark teeth, and fragments of gray marl.