Caves of the Mendip Hills Caves of the Mendip Hills The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain. The hills consist of anticlines of Carboniferous Limestone lying over Devonian Old Red Sandstone, with the sandstone exposed on the summits. When a surface stream running off the sandstone reaches the limestone it sinks below ground through a "swallet", (also known locally as a "slocker"), continuing on its way down towards sea level by
Cheddar, Somerset and Clifton Down Limestone of the Carboniferous Limestone Series, which contain ooliths and fossil debris on top of Old Red Sandstone, and by Dolomitic Conglomerate of the Keuper. Evidence for Variscan orogeny is seen in the sheared rock and cleaved shales. In many places weathering of these strata has resulted in the formation of immature calcareous soils. Cheddar Gorge, which is located on the edge of the village, is the largest gorge in the United Kingdom. The gorge is the site of the Cheddar Caves, where Cheddar Man was found in 1903. Older remains from the Upper Late Palaeolithic era