Sink Hole at the base of Mam Tor, Derbyshire

Originally uploaded for the Guesswhere UK group.

Along the western flank of Mam Tor and Rushup Edge are a series of sink holes where surface waters and streams flowing off the relatively low-permeability Mam Tor Beds and Edale Shales encounter the underlying Carboniferous Limestone. This one is near the old Windy Knoll Quarry. The water disappears underground and flows through an extensive network of cave passages before emerging at Peak Cavern and Russet Well in Castleton.