Oxford Clay

The Oxford Clay is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specifically, the Callovian and Oxfordian ages,[1] and comprises two main facies. The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.

Oxford Clay appears at the surface around Oxford, Peterborough and Weymouth and is exposed in many quarries around these areas. The top of the Lower Oxford Clay shows a lithological change, where fissile shale changes to grey mudstone. The Middle and Upper Oxford Clays differ slightly, as they are separated by an argillaceous limestone in the South Midlands.

The Callovo-Oxfordian Clay also occurs in the Paris Basin (France) and it is a potential host formation to dispose of high-level radioactive waste in France.

Oxford Clay
Stratigraphic range: Callovian-Oxfordian
OxfordClay Weymouth
TypeGeological formation
Unit ofAncholme Group
Sub-unitsPeterborough Member, Stewartby Member, Weymouth Member
UnderliesWest Walton Formation, Corallian Group
OverliesKellaways Formation
RegionOxford, Peterborough, Dorset, Yorkshire
Type section
Named forOxford


The Oxford Clay is well known for its rich fossil record of fish and invertebrates.[2] Many of the fossils are well preserved, occasionally some are found exceptionally well preserved. Animals which lived in the Oxford Clay Sea include plesiosaurs, marine crocodiles, ichthyosaurs, cephalopods (such as belemnites), bivalves (such as Gryphaea), and a variety of gastropods. Dinosaur eggs are stratigraphically present in the Lower Oxford Clay. Geographically, they are located in Cambridgeshire, England.[3]


Indeterminate euronithopod remains stratigraphically present in the Lower Oxford Clay and geographically located in Cambridgeshire, England.[3]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.


Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.


Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.


Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Economic use

Oxford Clay has a porous consistency and is soft and is often used in the making of roads. It is also the source of the Fletton stock brick of which much of London is built. For brick making, the Oxford Clay has the advantage of containing carbon which provides part of the fuel required in firing it so reducing the requirement for an external fuel source.

See also


  1. ^ "Oxford Clay Formation". The BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 21 August 2017.
  2. ^ Martill, D.M.; Hudson J.D. (1991). Fossils of the Oxford Clay. Palaeontological Association.
  3. ^ a b c d e f g h i j k l m n o p q r s "10.9 Cambridgeshire, England; 1. Lower Oxford Clay," in Weishampel, et al. (2004). Page 540.
  4. ^ "Table 18.1," in Weishampel, et al. (2004). Page 396.
  5. ^ Weishampel, et al. (2004). Pages 539-540.
  6. ^ a b "10.7 Dorset, England; 3. Lower Oxford Clay" and "cambridgeshire">"10.9 Cambridgeshire, England; 1. Lower Oxford Clay," in Weishampel, et al. (2004). Pages 539-540.
  7. ^ "10.7 Dorset, England; 3. Lower Oxford Clay," in Weishampel, et al. (2004). Page 539.
  8. ^ Listed as "?Lexovisaurus sp." in "10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  9. ^ "10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  10. ^ "Table 17.1," in Weishampel, et al. (2004). Page 367.
  11. ^ "Table 13.1," in Weishampel, et al. (2004). Page 265.
  12. ^ a b c d e f g "10.14 Oxfordshire, England; 8. Middle Oxford Clay," in Weishampel, et al. (2004). Page 540.
  13. ^ "Table 4.1," in Weishampel, et al. (2004). Page 72.
  14. ^ a b "10.14 Wiltshire, England; 4. Oxford Clay," in Weishampel, et al. (2004). Page 540.
  15. ^ Noé LF, Liston JJ, Chapman SD. 2010. ‘Old bones, dry subject’: the dinosaurs and pterosaur collected by Alfred Nicholson Leeds of Peterborough, England. Geological Society, London, Special Publications 343: 49–77.
  16. ^ Mark T. Young; Marco Brandalise de Andrade; Stephen L. Brusatte; Manabu Sakamoto; Jeff Liston (2013). "The oldest known metriorhynchid super-predator: a new genus and species from the Middle Jurassic of England, with implications for serration and mandibular evolution in predacious clades". Journal of Systematic Palaeontology. 11 (4): 475–513. doi:10.1080/14772019.2012.704948.


  • Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.

Further reading

  • Andrews, C. W. 1910. "A Descriptive Catalogue of the Marine Reptiles of the Oxford Clay, Part I". British Museum (Natural History), London, England: 205 pp.
  • Andrews, CW. 1913. A descriptive catalogue of the Marine Reptiles of the Oxford Clay, Part II. British Museum (Natural History). pp. 205pp.
  • M. J. Benton and P. S. Spencer. 1995. Fossil Reptiles of Great Britain. Chapman & Hall, London 1-386
  • J. B. Delair. 1973. The dinosaurs of Wiltshire. The Wiltshire Archaeological and Natural History Magazine 68:1-7
  • P. M. Galton. 1980. European Jurassic ornithopod dinosaurs of the families Hypsilophodontidae and Camptosauridae. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 160(1):73-95
  • D. M. Martill. 1988. A review of the terrestrial vertebrate of fossils of the Oxford Clay (Callovian-Oxfordian) of England. Mercian Geologist 11(3):171-190

Callovosaurus (meaning "Callovian lizard") is a genus of iguanodontian dinosaur known from most of a left thigh bone discovered in Middle Jurassic-age rocks of England. At times, it has been considered dubious or a valid genus of basal iguanodontian, perhaps a dryosaurid.


Cetiosauriscus ( SEE-tee-oh-SOR-iss-kəs) is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian (Middle Jurassic Period) in what is now England. A herbivore, Cetiosauriscus had—for sauropod standards—a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about 15 m (49 ft) long and between 4 and 10 t (3.9 and 9.8 long tons; 4.4 and 11.0 short tons) in weight.

The only known fossil that was later named Cetiosauriscus includes most of the rear half of a skeleton as well as a hindlimb (NHMUK R3078). Found in Cambridgeshire in the 1890s, it was described by Arthur Smith Woodward in 1905 as a new specimen of the species Cetiosaurus leedsi. This was changed in 1927, when Friedrich von Huene found NHMUK R3078 and the C. leedsi type specimen to be too different from Cetiosaurus, warranting its own genus, which he named Cetiosauriscus, meaning "Cetiosaurus-like". Cetiosauriscus leedsi was referred to the sauropod family Diplodocidae because of similarities in the tail and foot, and had the dubious or intermediate species "Cetiosauriscus" greppini, "C." longus, and "C." glymptonensis assigned to it. In 1980, Alan Charig named a new species of Cetiosauriscus for NHMUK R3078 because of the lack of comparable material to the type of C. leedsi; this species was named Cetiosauriscus stewarti. Because of the poor state of preservation of the Cetiosauriscus leedsi fossil, Charig sent a petition to the International Commission on Zoological Nomenclature to instead make C. stewarti the type species. Cetiosauriscus stewarti became the oldest confirmed diplodocid until a phylogenetic analysis published in 2003 instead found the species to belong to Mamenchisauridae, and followed by studies in 2005 and 2015 that found it outside Neosauropoda, while not a mamenchisaurid proper.

Cetiosauriscus was found in the marine deposits of the Oxford Clay Formation alongside many different invertebrate groups, marine ichthyosaurs, plesiosaurs and crocodylians, a single pterosaur, and various dinosaurs: the ankylosaur Sarcolestes, the stegosaurs Lexovisaurus and Loricatosaurus, the ornithopod Callovosaurus, as well as some unnamed taxa. The theropods Eustreptospondylus, Metriacanthosaurus and Megalosaurus are known from the formation, although probably not from the same level as Cetiosauriscus.


Cryptoclidus ( krip-toh-KLY-dəs) is a genus of plesiosaur reptile from the Middle to Late Jurassic period of England, France, Argentina and Cuba.

Furzy Cliff

Furzy Cliff is located on the coast near the village of Preston, just to the east of Weymouth, Dorset, England. It is at the northeastern end of Weymouth Beach, looking out over Weymouth Bay to Portland Harbour and the Isle of Portland. Close by to the east is Bowleaze Cove. Just inland to the north are Jordan Hill and the remains of the Jordan Hill Roman Temple. On the top of the cliff there is a large grass area with good views.Furzy Cliff consists of Oxford Clay with a thin Corallian Limestone layer over this. Mudslides frequently occur on the narrow undercliff and the base is mainly made up of clay material.

Fossilized examples of Gryphaea dilatata, commonly called "devil's toenail", an extinct species of Jurassic oyster, can be found in the Oxford Clay.

In 1816–17, the artist John Constable painted Weymouth Bay: Bowleaze Cove and Jordon Hill, including Furzy Cliff, while on his honeymoon, viewed from the beach at Bowlease and looking west. The painting is now in the National Gallery, London.


Lexovisaurus is a genus of stegosaur from mid-to-Late Jurassic Europe, 164.7 mya. Fossils of limb bones and armor fragments have been found in middle to late Jurassic-aged strata of England and France.


Liopleurodon (; meaning 'smooth-sided teeth') is a genus of large, carnivorous marine reptile belonging to the Pliosauroidea, a clade of short-necked plesiosaurs. The two species of Liopleurodon lived during the Callovian stage of the Middle Jurassic Period (c. 164 to 155 mya). It was the apex predator of the Middle to Late Jurassic seas that covered Europe. The largest species, L. ferox, is estimated to have grown up to 6.4 metres (21 ft) in length.The name "Liopleurodon" (meaning "smooth-sided tooth") derives from Ancient Greek words: λεῖος leios, "smooth"; πλευρά pleurá, "side" or "rib"; and ὀδόν odṓn, "tooth".


Loricatosaurus (meaning "armored lizard") is a dinosaur of Stegosauridae family from Callovian-age (Middle Jurassic) rocks of England and France.


Marmornectes is a genus of pliosaurid known from the Middle Jurassic of Bedfordshire, United Kingdom.


Metriorhynchus is an extinct genus of marine crocodyliform that lived in the oceans during the Middle to Late Jurassic. Metriorhynchus was named by the German palaeontologist Christian von Meyer in 1830. Metriorhynchus was a carnivore that spent much, if not all, its life out at sea. No Metriorhynchus eggs or nests have been discovered, so little is known of the reptile's life cycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Metriorhynchus mated, whether on land or at sea, is currently unknown. The name Metriorhynchus means "Moderate snout", and is derived from the Greek Metrio- ("moderate") and -rhynchos ("snout").


Muraenosaurus (from the Latin "Muraena" meaning "eel" and "Sauros" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appearance of the long neck and small head. Muraenosaurus grew to lengths between 5 metres (16 ft) and 6 metres (20 ft) and dates roughly to between 160 Ma (million years ago) and 164 Ma in the Callovian of the middle Jurassic. Charles E. Leeds collected the first Muraenosaurus which was then described by H. G. Seeley. The specimen may have suffered some damage due to the casual style of Charles Leeds’ collection. The first Muraenosaur was recovered with pieces missing from the skull and many of the caudal vertebrae absent. Because the animal was described from Charles Leeds’ collection it was given the name Muraenosaurus Leedsi. M. leedsi is the most complete specimen belonging to the genus Muraenosaurus and also the only species that is undoubtedly a member of the genus. . Two other species have been tentatively referred to as members of the genus Muraenosaurus: M. reedii and Picrocleidus beloclisMuraenosaurus reedii was discovered in Wyoming and described by Maurice Mehl of the University of Chicago. The fossilized fragments found consisted of pieces of the pectoral and pelvic girdles, several vertebrae, ribs, and a relatively complete left pectoral paddle. Connections between M. leedsi and M. reedii were drawn when examining the ribs structure and paddle of M. reedii. Both had a similarly shaped, elongated humerus and relatively short phalanges. The species M. reedii is in fact a junior synonym of Pantosaurus. Picrocleidus beloclis is another plesiosaur originating in the middle Jurassic and found in the Oxford clay formation. Picrocleidus has previously been considered synonymous with Muraenosaurus although there are doubts in the relationship between the two groupings.


Pachycostasaurus (meaning 'thick - ribbed lizard') is an extinct Pliosauroid from the Oxford Clay formation of Peterborough, England.


Peloneustes (meaning 'mud swimmer') is an extinct genus of sauropterygian reptile belonging to the family Pliosauridae. It is known from the Callovian aged (Middle Jurassic) deposits of the Oxford clay formation of England. With a length of around 3 metres (9.8 ft), it was one of the smallest representatives of the group.

Like its larger relatives, Peloneustes had a short neck and long jaws capable of grabbing large prey. Its streamlined body allowed it to chase fast prey such as belemnites. As it had fewer and blunter teeth than its relatives, it is thought to have mainly fed on hard prey such as ammonites.


Picrocleidus is an extinct genus of plesiosaur. It is known only from the type species P. beloclis from the Middle Jurassic Oxford Clay Formation (Callovian stage) of the United Kingdom.

Redcliff Point

Redcliff Point is on the south coast of England, to the east of Weymouth in Dorset. It lies just past the eastern end of the sweeping Weymouth Bay on the Jurassic Coast, a UNESCO World Heritage landscape known for its geology. Fossils can be found in the Upper Oxford Clay in this area.The cliff looks over to the Isle of Portland. It is so-called because of the red colouring of the cliffs at this point.Close by to the west are the Broadrock cliffs and Bowleaze Cove. To the east are Black Head and the coastal village of Osmington Mills.


Sarcolestes (meaning "flesh robber") is an extinct genus of ankylosaurian ornithischian dinosaur from the Oxford Clay of England. The current type and only species is S. leedsi, and the holotype is a single partial left mandible. The genus and species were named in 1893 by Richard Lydekker, who thought they belonged to a theropod.


Simolestes (meaning "hearkening thief") is an extinct pliosaurid genus that lived in the Middle to Late Jurassic. The type specimen, BMNH R. 3319 is an almost complete but crushed skeleton diagnostic to Simolestes vorax, dating back to the Callovian of the Oxford Clay formation, England. The genus is also known from the Callovian and Bajocian of France (S.keileni), and the Tithonian of India (S.indicus). The referral of these two species to Simolestes is dubious, however.


Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Middle Jurassic (Toarcian to Callovian). Fossil specimens have been found in England, France, Germany, Switzerland and Morocco. The largest species, S. heberti, reached up to 5 metres (16 ft) in length, though 2.5 to 3.5 metres (8.2 to 11.5 ft) was more common.


Tricleidus is an extinct genus of cryptoclidid plesiosaur known from only specimen (BMNH R3539) from the middle Jurassic of United Kingdom. It was first named by Andrews in 1909 and the type species is Tricleidus seeleyi.


Tyrannoneustes is an extinct genus of geosaurine metriorhynchid crocodyliform from the Middle Jurassic Oxford Clay Formation of England. It contains a single species, Tyrannoneustes lythrodectikos, meaning "blood-biting tyrant swimmer". The genus was rediscovered after a century of storage in a museum basement after being unearthed by fossil hunter Alfred Nicholson Leeds between the years of 1907 and 1909. Its lower jaw measured about 26 inches long and its teeth were blade-like, likely built to attack prey as large or larger than itself, similar to the Late Jurassic Dakosaurus, Torvoneustes, and Plesiosuchus.

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