Cascades formed by calcareous concretions on a steep break in the slope of a stream are often called ‘tuff cascades’. They can be very active - like the waterfalls of Baume-les-Messieurs and Planches-près-Arbois in Jura (photo) - or at the end of their life, like that of Les Pertes de l'Ain, or even completely dried up like the deposits of an old waterfall in the bottom of the Planches valley.