Figure 15.1 Map of bottom relief forms in the northeastern Caspian Sea and old coastlines, compiled from pictures taken from Soyuz 22, September 19, 1976. The letters a, b, and c mark features compared among figures. Key to bottom relief forms: 1, underwater ridges, (1a, of supposed wave-formed origin; 1b, ridges now forming); 2, banks and sandbars of complex origin. Numbers 3-9 comprise a series of underwater ridges and inter-ridge depressions formed by waves and wind-induced surges: 3, sharp crests of relict ridges and those now forming; 4, underwater crests of ridges now forming at the water surface; 5, underwater crests of ridges now forming at significant depths; 6, underwater crests of ridges in early stages of formation at significant depths; 7, low slopes of underwater ridges; 8, inter-ridge depressions with hollows now forming; 9, inter-ridge hollows in early stages of formation. 10, Contemporary erosional hollows formed by wind-induced surges; 11, relict channels shown in contemporary relief; 12, relict channels separated by special bottom vegetation.