Sip back and discover Somerset and explore Cheddar Gorge an ancient landmark of Carboniferous Limestone, fossiliferous in parts with archaeological artifacts, located in the Mendip Hills National Landscape. A familiar uplifted massif and exposed ancient seabed to the West of England only a short distance from the south of Bristol. Cheddar Gorge is the largest gorge in the United Kingdom carved out by glacial meltwaters released during the many freezing and thawing cycles of the ground near to the glaciers of the British-Irish Ice Sheet reaching as far south as South Wales at the Last Glacial Maximum over the last 1.2 million years. The underground karst landscape of the Cheddar Gorges caves, sinkholes, springs, and sinking streams plus the speleothems of stalagmites and stalactites were formed both by the erosion and of the limestone during the warmer interglacial periods as well as long term deposition of minerals from groundwater. All in all this limestone landscape makes up Britain's largest underground river system.
Cheddar Gorge is nearly 5 Km long and in some places the near-vertical cliff-face reaches over 137 metres in height. This is a place to be experienced whether walking or taking to the road and either driving of cycling the 23Km of twists and turns of the B3135 or Cliff Road that takes in Cheddar Gorge between Ashwick on to the village of Cheddar regarded as one of Somerset’s most spectacular and scenic roads.
The experience of travelling through Cheddar Gorge is then tipped by buying your Cheddar Gorge & Cave Explorer ticket to visit the spectacle of Gough's Cave and Cox's Cave two of Britain’s oldest show caves and maybe afterwards a pub lunch or pop into the Cheddar Ales tap room for a half of Potholer their multi-award-winning golden pale ale - cheers!
The county of Somerset is often an underrated but good location for fossil hunting though mainly it is focussed along the coastline. Among Somersets fossil highlights includes the discovery of a tooth of the earliest and now extinct species of Hippopotamus (Hippopotamus antiquus) to live Britain during the Early Pleistocene. Dated from between 1.5 to 1.07 million years ago This tooth was discovered at the collapsed Westbury Cave in the privately owned Westbury Quarry located between Cheddar and Wells.
Near to the seaside village of East Quantoxhead (51.1909°N 3.2364°W 0.90) is the internationally recognised reference point and first UK Jurassic “Golden Spike” agreed by the Global Boundary Stratotype Sections and Points (GSSPs) for the lower boundary of the Sinemurian Stage. This is a 27 meter deep Blue Lias Formation (part of the Lias Group) close to Lime Kiln Steps leading down to the beach.
The Sinemurian Stage overlies the Hettangian Stage and underlies the Pliensbachian Stage and is the second of the four divisions of the Lower Jurassic Epoch whose marine deposits were laid down between 199.5 - 192.9 million years ago. A similar fossiliferous geological sequence is also present as far North as the foreshore of Redcar on the Yorkshire-Cleveland Coast.
The Sinemurian Stage was named in 1849 in the publication, Cours élémentaire de paléontologie et de géologie stratigraphiques, by French palaeontologist and naturalist Alcide Dessalines d' Orbigny after Sinemurum Briennense Castrum the Roman name for the small-medieval town of Semur-en-Auxois in the heart of the Côte-d'O on the banks of the Armançon. Here also ammonites and other fossils were discovered during the excavations and construction around the town and are today displayed at the Semur-en-Auxois Museum.
The fossils found in East Quantoxhead include species of arietitid ammonites such as Vermiceras quantoxense, Vermiceras palmeri and Metophioceras along with a variety of microscopic calcium carbonate shells of Foraminifera a single-celled organism called Lingulina, Planularia and Frondicularia. Also a very small crustacean called an Ostracods named Ogmoconchella.
As mentioned fossil hunting in Somerset is mainly focussed along the coastline where Jurassic Period rock exposes ammonites at Watchet and Kilve and Triassic Period rock formations exposed at Blue Anchor Bay, Lilstock and Aust hold fossils of reptiles, fish and marine reptile fossils such as the giant 25-meter Ichthyosaur called Ichthyotitan severnensis (meaning “giant fish lizard of the Severn”) found along the Severn Estuary and now on display at the Bristol Museum and Art Gallery.
Around Weston-Super-Mare, Clevedon and Portishead the Carboniferous Limestone contains crinoids, corals and brachiopods. Further south towards the Minehead and close to the Butlin's holiday camp the exposed cliffs of Hangman Sandstone have recently revealed the oldest fossilised forest known on Earth. Made up of Calamophyton these plants resemble palm trees and have been described as the ‘prototype’ for modern-day trees dating back to the Middle Devonian Period and the Eifelian Stage between 393.3 - 387.7 million years ago.
Both Cheddar Gorge and the wider Mendip Hills has a complex geological history for a comparatively small area. The Mendip Hills began to form over 400 million years ago during the Silurian and Devonian periods when this area was covered by a shallow tropical sea but it was not until the Carboniferous Period that significant limestone accumulation began to happen across the UK forming what is defined as the Carboniferous Limestone Supergroup.
This Carboniferous Limestone Supergroup was extensively deposited across England and Wales between the Tournaisian Age and Viséan Age an interval of 28 million years from 358.9 - 330.9 million years ago. Members of the Carboniferous Limestone Supergroup are present in the south and west of Cumbria, the Yorkshire Dales, North and South Wales, the Peak District and underlays much of the Bristol and Mendip Hills.
During the Carboniferous Period much of what is now the United Kingdom was located near the equator and submerged beneath the warm and shallow tropical Rhetic Ocean regarded as the most important ocean of the Paleozoic Era. The Rhetic Ocean lay between the two major continents of Laurentia and Gondwana from the Early Ordovician until it closed during an extended sequential series of collisions of these continents and tectonic subduction to create the Supercontinent of Pangea.
Ultimately, the closure of the Rhetic Ocean changed the global landscape as the immense forces exerted by the tectonic plates compressed, folded, faulted and uplifted previously submerged rock to the surface including the Carboniferous Limestone at Cheddar Gorge and the Mendip Hills. Erosion would then play a significant role in shaping and carving the limestone into the steep-sided gorge and unground karst system we see today.
Cheddar Gorge exposes the Clifton Down Limestone Formation a member of the Carboniferous Limestone Supergroup and was previously known as the Cheddar Limestone Formation. Dated to between the Arundian and Holkerian Substages of the Viséan Age the Clifton Down Limestone Formation combines with outcrops of Cheddar oolite and Burrington Oolite and the younger Oxwich Head Limestone dated to between the Asbian and Brigantian Substages of the later Viséan Age.
Though this limestone represents an accumulation of carbonate sediments formed from the remains of marine organisms such as corals, crinoids, brachiopods, and foraminifera that thrived in the warm nutrient-rich waters. The Clifton Down Limestone Formation is generally understood to be a bioclastic limestone with a low diversity of fossils of shallow marine benthic or seabed living fauna.
The fossils exposed at Cheddar Gorge include communities of brachiopods known as Composita, Megachonetes, Linoprotonia, Davidsonina and extinct colonial rugosa corals of Siphonodendron and Carcinophyllum.
The underground karst scenery of Cheddar Gorge was also home to Cro-Magnons the first modern humans anatomically like us today to settle Britain after the last ice age 14,700 years ago. The community at Cheddar Gorge are known as the "Horse Hunters" part of the Magdalenian hunter-gatherer people to have migrated from across the land bridge of Doggerland from continental Europe before it was submerged by rising sea levels. Interestingly, the archaeology of these people suggests they were cannibals!
In 1903 a skeleton of a 10,000 year old Mesolithic hunter-gatherer known as "Cheddar Man" was discovered making it the oldest and almost complete skeleton of a Homo sapien ever found in Britain (now on display at the Natural History Museum in London – Human Evolution Gallery).
In 2023 the Mendip Hills were described as a “super” National Nature Reserve by Natural England with the goal to conserve and help restore over 1,400 hectares of steep limestone slopes, traditional wildflower grasslands, ancient wooded combes, gorges and rocky outcrops bringing together 31 existing nature sites with more than 400 hectares of additional land.
Cheddar Gorge is part of the Mendip Hills AONB and Somerset Wildlife Trust’s Cheddar Complex of three nature reserves at Black Rock, Long Wood and Velvet Bottom.
With the goal to protect against habitat loss and preserve biodiversity the limestone scenery of Cheddar Gorge and the Mendip Hills is a place where plant and animal life can flourish including the rare and endemic plants such as Little Robin (Geranium purpureum), Purple Gromwell (Buglossoides purpurocaerulea) and fragrant Cheddar Pink (Dianthus gratianopolitanus).
Amongst the wildlife to benefit are not only the feral goats that roam the area but also one of the smallest and nationally endangered Lesser Horseshoe Bat (Rhinolophus hipposideros) and its larger relative the Greater Horseshoe Bat (Rhinolophus ferrumequinum). Others include the Black Oil Beetle (Meloe proscarabaeus), the Small Pearl-Bordered Fritillary butterfly (Boloria selene) and Hazel Dormouse (Muscardinus avellanarius), Water Vole (Arvicola amphibius) Skylark (Alauda arvensis) and Britain's only venomous snake the Adder (Vipera berus).
Among the supporters of the “super” National Nature Reserve is Lord Bath of Longleat Estate who is quoted in a UK Government Press Release from Department for Environment, Food & Rural Affairs and Natural England in October 2023
"Cheddar Gorge is one of Britain’s most spectacular natural landmarks, comprising a large and significant part of the Mendip Hills’ footprint and bio connectivity. As a private landowner of part of this special piece of Britain, we take our responsibility as custodians extremely seriously. Through the Cheddar Gorge and Caves enterprise, we work to attract many people to this area to enjoy and experience this outstanding part of the world. In addition, we work tirelessly to ensure this amazing mosaic of land is conserved for future generations of visitors to enjoy and populations of diverse wildlife to thrive."