Steephead valley

A steephead valley, steephead or blind valley is a deep, narrow, flat bottomed valley with an abrupt ending. Such valleys arise in limestone or karst landscapes, where a layer of permeable rock lies above an impermeable substrate such as marl. They are created by a stream flowing within the permeable rock and eroding it from within, until the rock above collapses opening up a steep narrow valley which is then further eroded by the stream running across the impermeable valley floor. At the head of the valley the stream emerges from the rock as a spring. Notable examples can be found in the Jura region of France, for example the Reculée de Baume at Baume-les-Messieurs and the Reculée d'Arbois with its head at Les Planches-près-Arbois and its exit at Arbois.