1. A karst valley abruptly terminated by the passage underground of the watercourse which has hitherto resisted the karst processes and remained at the surface. An intermediate type, the half-blind valley, exists in which the valley form continues downstream from the sinkhole used under conditions of normal river flow. The watercourse only flows here intermittently and the valley may (except for its use as a flood conduit) be fossil in that it represents the section abandoned by the river as it sought progressively higher swallow holes [19]. 2. A karst valley with no evident downstream continuation, and one in which the water drains and disappears underground into one or more ponors [20]. 3. A valley that terminates abruptly at a point where its stream sinks, or once sank, underground. As sinks develop higher up the blind valley, the original valley termination may be dry under most flow conditions [9]. Related to marginal polje. Synonyms: (French.) vallee aveugle; (German.) Blindtal, (Kesseltal); (Greek.) kliste karstike kilas; (Italian.) valle cieca, valle chiusa; (Russian.) slepaja dolina; (Spanish.) valle ciego; (Turkish.) kor vadi; (Yugoslavian.) slijepa dolina, sepa dolina. See also half-blind valley; marginal polje.