canyonsarroyosbadlandscliffssubmarine canyonsvalleysbarrancasravinesquebradasgulchesgorgesflumes (natural)chasms Relatively narrow, deep depressions with steep sides, the bottom of which generally has a continuous slope [NIMA GEONet Designation ... Definitions http://164.214.2.59/gns/html/desig.html]