Sand wave
A sand wave is frequently defined as a type of usually a large, ridge-like bathymetric feature, called a bedform, that is created by the interaction between underwater unidirectional currents with noncohesive, granular sediment, e.g., silt, sand, and gravel and lies transverse to the flow of these currents. There exists a lack any universally accepted classification scheme among sedimentologists, geologists, and other Earth scientists that precisely defines the difference between sand waves and similar bedforms, such as ripples, megaripples, subaqueous dunes, and sediment waves.