The Mendips
have a rich 'geodiversity' which means there is a large range of
rock types exposed in a small area. This superb diversity of rock
types, ranging from Silurian to Jurassic in age, are exposed in many
natural rock outcrops, particularly in the western Mendips where
the limestone gorges and caves at Cheddar and Wookey are national
tourist icons. On eastern Mendip, natural rocky outcrops are largely
confined to the intimate twisting largely wooded valleys and quarries.

These natural exposures have been augmented by numerous quarries
which significantly increase the local geodiversity. Many key geological
sites, especially in eastern Mendip are in quarries. The most important
sites have been designated as Sites of Special Scientific Interest
(SSSI's) on the basis of their biological, geological or geomorphological
significance. Several quarries, including the disused quarries at
Vallis Vale and Great Elm, and the operational or dormant quarries
at Cloford, Holwell, Moon's Hill and Cook's Wood Quarry, have this
designation. Further details can be found in the Natural England
website at www.naturalengland.org.uk/
Some sites, notably at Tedbury Camp Quarry, have been cleaned up
in the past to allow safe access and display the geological features to
their best advantage.

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Quarries offer several
advantages for studying geology:
- They increase the 'geodiversity' of a region
- They have fresh broken faces which clearly display the rocks
- The absence of vegetation allows the rocks to be clearly seen
- Quarrying opens up new exposures where rocks would not otherwise
be seen
- They often expose a range of rock types
Because of their superb exposures, Mendip quarries have attracted
the interest of geologists since geology began as a science in the
early 19th century. The classic unconformity section exposed in quarries
at Vallis Vale was described by Sir Henry de la Beche in the world's
first geological survey memoir in 1846. Another early scientist was
Charles Moore who in the 1850s and 60s, examined the quarries at
Holwell where he found deep fissures in the Carboniferous Limestone
infilled with younger Triassic and Jurassic material. This material
contained numerous remains of reptiles and early mammals. He also
discovered the Silurian igneous rocks at the core of the Beacon Pericline,
which led to the development of Moon's Hill, Downhead and other hard
rock quarries.

In recognition of their geological value, in recent times the Mendip
quarry companies have developed a very close and proactive relationship
with visiting groups and the public, probably better co-ordinated
than any other area in the UK. In particular, Hanson pioneered a
visitor friendly approach with their East Mendip Study Centre. Foster
Yeoman Ltd. (now taken over by Aggregate Industries), the operator
of Torr Works quarry has also been innovatory and, like Hansons has
offered pre-booked visits to individual members of the public. Although
these services are geared mainly to schools and colleges, geological
and other interest groups are also hosted. Several quarry companies
are combining forces to invest in a new education centre, which is
being planned just south of Stoke St Michael.
The quarry companies have also facilitated a 'Geodiversity Audit
of Active Aggregates Quarries' in the region, including Whatley,
Colemans, Torr Works, Gurney Slade, Halecombe, Moon's Hill and Dulcote
quarries. In 2004, detailed examination of numerous geological features
at each of these sites was recorded and reported and is available
as a CD from Somerset
County Council (see their website for details).
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