Several old relict caves occur on western Mendip, the largest being Shute Shelve Cavern on Axbridge Hill. Originally discovered by ochre miners, the cave is a large old phreatic passage with much red and yellow ochre. On the western end of Banwell Hill are the Banwell Bone and Stalactite Caves. Discovered by miners in 1757, the Stalactite Cavern was open to the public for a while. The Bone Cave was discovered much later in 1824 and contained vast numbers of animal bones dating back from the early part of the last glaciation about 80 000 years ago. Many other small relict caves occur, some of which have been investigated by ochre miners.
Several caves occur on Sandford Hill, the largest being Mangle Hole. The bottom of this cave intersects the underground river feeding Banwell Risings.