1. A spoon-shaped hollow carved in a cave wall, floor or ceiling due to erosion by eddies in flowing water. Scallops are commonly closely packed, leaving sharp ridges at the intersects. They range from 10mm to 1m in length and as a general rule the smaller they are then the faster flowing was the water that carved them. The scallops are generally asymmetrical, with their upstream end steeper than the downstream end - a useful indicator of paleo-flow direction in abandoned passages [9]. 2. Oval hollow having an asymmetric cross section along its main axis. Scallops form patterns on the walls of caves and in streambeds and may be used to determine direction of flow of turbulent water, since they are steeper on the upstream side. Commonly called flutes in America [10]. Synonyms: (French.) cannelure, vague d'erosion; (German.) in Fliebrichtung des Wabers ausgezogener Kolk; (Greek.) kilon ooithes; (Spanish.) huella de corriente; (Turkish.) degirmi, tarak. See also flute.