Wave-formed ripple Wave-formed ripple In sedimentology, wave-formed ripples or wave-formed ripple marks are a feature of sediments (sandstones, limestones, siltstones) and dunes. These ripple marks are often characterised (and thus distinguished from current ripples) by symmetric cross sections and long relatively straight crests, which may commonly bifurcate. Commonly, these crests can be truncated by subsequent flows. Their wavelength (periodicity) depends on the sediment grain size, water depth and water-particle orbits in the waves. On tidal flats the pattern of wave-formed ripples may be complicated, as a product of changing depth and wind and tidal runoff directions. Symmetrical ripples are commonly found in
Bowditch Crests Bowditch Crests Bowditch Crests () is a line of precipitous cliffs surmounted by four summits on Bermel Peninsula in eastern Graham Land. The feature was photographed from the air by Lincoln Ellsworth in November 1935 and was mapped from these photos by W.L.G. Joerg. It was surveyed by the Falkland Islands Dependencies Survey in 1958, and named by the UK Antarctic Place-Names Committee for Nathaniel Bowditch, American astronomer and mathematician, author of "The New American Practical Navigator" (1801) which firmly set out the practical results of theories established at that date and has since gone through more than 56 editions.