At Cloford Quarry the unconformity between the Inferior oolite above and the Carboniferous Limestone below is exposed. In this quarry is a cave that has been formed in close association with the plane that separates the two lithologies. Some of the passages are formed in both and some only in one. The roof of the cave is nowhere more than 3 m below the surface. All passages owe their origin to solution by running water. Collapse has altered some. A developmental sequence is postulated and the effects of joint control are stressed.