Gorge is the finest example of a limestone gorge in Britain,
and its cliffs support many valuable semi-natural habitats, home
to a wide range of plant species, many of them rare. At the lower
end of the gorge are two show caves which together attract half
a million visitors a year.
Contrary to popular belief, Cheddar Gorge is not a collapsed cavern,
but a fine example of a gorge cut by a surface river, and since left
high and dry as drainage went underground. The gorge was formed by
meltwater floods during the many cold periglacial periods over the
last 1.2 million years. During these arctic episodes, the development
of permafrost blocked the caves with ice and frozen mud. Snowmelt
floods during the brief summers were forced to flow on the surface,
carving out the gorge in the process.
Each successive periglacial episode caused further erosion. During
the warmer interglacial periods, drainage was underground, creating
the caves and leaving the gorge dry.
Aerial view of Cheddar Gorge (click to enlarge view).
The Gorge is cut into the Carboniferous
Limestone, which here dips at about 20° to the south-west.
As you travel down the gorge the dip causes successively younger
rocks to descend to road level. The pale grey Burrington Oolite.
outcrops around Black Rock Gate, while most of the gorge is cut into
the Clifton Down Limestone (including the Cheddar Limestone
and Cheddar Oolite). At the base of the gorge the Oxwich Head Limestone
occurs at road level. The cliffs on the south side are dominantly
vertical, cut along major fractures whereas the northern slopes are
formed along the dipping bedding planes.
The Geology of Cheddar Gorge (click to enlarge view).
There are many mostly small caves in Cheddar Gorge, but the two largest,
Gough's Cave and Cox's Cave are open to the public. Gough's Cave,
discovered by Richard Gough in 1898, was formed by the ancestral
River Yeo over 120 000 years ago. Just inside the entrance remains
of several human skeletons, including the 9000-year-old Cheddar Man,
were found along with many other archaeological artifacts.
The show cave follows the former route of the underground river through
several well decorated chambers. The underground river has now found
a new lower route, discovered by cave divers in 1985, and emerges
to daylight at Cheddar Risings. Cox's Cave was discovered by George
Cox in 1837 and contains many stalactites and stalagmites. Several
other small caves exist in the cliffs above, remnants of earlier
courses of the underground River Yeo, long since abandoned by down-cutting
of the gorge. Many are home to roosting and hibernating bats, including
significant numbers of the greater horseshoe bat.
Flora and fauna
The limestone crags and cliff faces are home to many plant species,
including slender bedstraw and lesser meadow-rue, and the rare and
protected Cheddar pink. The thin dry limestone soils on south-facing
slopes support grasslands which are important for insects and
Several quarries once operated on the Cheddar area. The largest,
Batts Coombe Quarry, is still operational. This quarry is developed
in the Burrington Oolite, a very pure limestone (over 98% CaCO3),
used for making quicklime, an essential material for the steel
industry. It is one of only five sites producing the substance
nationwide. Stone was once quarried from Cheddar Gorge but public
opposition and a landslide caused the site to close down by 1912.