hydrographic feature undersea feature ENVO ENVO:00000104 EcoLexicon:fan EcoLexicon:platform EcoLexicon:ravine FTT:1020 FTT:1137 FTT:1176 FTT:1193 FTT:1194 FTT:1195 FTT:1196 FTT:5 FTT:810 FTT:984 Geonames:FRKU Geonames:FRSU Geonames:MDVU Geonames:PLFU Geonames:RAVU Geonames:RMPU Geonames:U.BSNU Geonames:U.EDGU Geonames:U.ESCU Geonames:U.FANU Geonames:U.FLTU Geonames:U.FURU Geonames:U.GAPU Geonames:U.GLYU Geonames:U.HOLU Geonames:U.LDGU Geonames:U.LEVU Geonames:U.PLNU Geonames:U.PLTU Geonames:U.PNLU Geonames:U.PRVU Geonames:U.RDGU Geonames:U.RDSU Geonames:U.RISU Geonames:U.SDLU Geonames:U.SHVU Geonames:U.SILU Geonames:U.SPRU Geonames:U.TERU Geonames:U.VALU Geonames:U.VLSU TGN:23001 TGN:23116 TGN:23117 TGN:23118 TGN:23135 TGN:23162 TGN:23181 TGN:23182 TGN:23183 TGN:23184 TGN:23188 TGN:23192 TGN:23193 TGN:23194 TGN:23195 TGN:23196 TGN:23211 TGN:23212 TGN:23301 TGN:23411 TGN:23412 TGN:23413 TGN:23415 TGN:23421 TGN:23423 TGN:23424 TGN:23431 TGN:23453 TGN:23461 TGN:23463 TGN:23467 TGN:23550 basin escarpment fan flat fork forks furrow gap gully hole hole (seafloor) ledge levee median valley moat (seafloor) ocean floor feature pinnacle plain plateau platform province ramp ramp (seafloor) ravine ridge ridges rise rise (seafloor) saddle seafloor feature shelf edge sill spur subsea feature terrace tongue (seafloor) undersea bank undersea basin undersea bench undersea cliff undersea fan undersea fork undersea fracture zone undersea furrow undersea gap undersea hole undersea ledge undersea levee undersea median valley undersea moat undersea peak undersea pinnacle undersea plain undersea platform undersea ramp undersea rise undersea saddle undersea shelf undersea shelf edge undersea shelf valley undersea sill undersea slope undersea spur undersea terrace undersea tongue undersea valley underwater feature valley valleys