The Oxford Clay (or Oxford Clay Formation) 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, 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.
Palaeontology The Oxford Clay is well known for its rich fossil record of fish and invertebrates. 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.
Fossil Content
Dinosaurs Ornithischians Indeterminate euronithopod remains stratigraphically present in the Lower Oxford Clay and geographically located in Cambridgeshire, England.
Ornithischians of the Oxford Clay Genus Species Location Stratigraphic position Material Notes ImagesCallovosaurusC. leedsi CambridgeshireLower"Femur.""Table 18.1," in Weishampel, et al. (2004). Page 396. An iguanodontian dryosaur.LexovisaurusWeishampel, et al. (2004). Pages 539-540.L. durobivensis"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. Cambridgeshire"10.9 Cambridgeshire, England; 1. Lower Oxford Clay," in Weishampel, et al. (2004). Page 540. Dorset"10.7 Dorset, England; 3. Lower Oxford Clay," in Weishampel, et al. (2004). Page 539.Lower A holotype pelvis. A stegosaurIndeterminateListed as "?Lexovisaurus sp." in "10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540. Bedfordshire"10.10 Bedfordshire, England; 1. Oxford Clay," in Weishampel, et al. (2004). Page 540.LoricatosaurusL. priscus CambridgeshireLower A stegosaur.SarcolestesS. leedsi CambridgeshireLower"Partial mandible.""Table 17.1," in Weishampel, et al. (2004). Page 367. An ankylosaur.
Saurischians Saurischians of the Oxford Clay Genus Species Location Stratigraphic position Material Notes Images CetiosauriscusC. stewarti Cambridgeshire Lower"Rear half of a skeleton.""Table 13.1," in Weishampel, et al. (2004). Page 265. Eustreptospondylus"10.14 Oxfordshire, England; 8. Middle Oxford Clay," in Weishampel, et al. (2004). Page 540.E. oxoniensis Oxfordshire UpperDisarticulated skull and skeleton, with some referred limb elements."Table 4.1," in Weishampel, et al. (2004). Page 72.SauropodaIndeterminate Wiltshire"10.14 Wiltshire, England; 4. Oxford Clay," in Weishampel, et al. (2004). Page 540. CambridgeshireThe caudal vertebrae from Cambridgeshire were mistakenly considered part of the syntypic series of "Ornithopsis" leedsi by Upchurch and Martin (2003).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.TheropodaIndeterminate OxfordshireMiddleMetriacanthosaurusM. parkeri WeymouthUpper
Pterosaurs Additional indeterminate pterosaur material is stratigraphically present in the Weymouth and Peterborough Members. Pterosaurs of the Oxford Clay Genus Species Location Stratigraphic position Material Notes Images Rhamphorhynchinae indet. Stewartby Member Scapulocoracoid, humerus, ulna Possibly cf. Rhamphorhynchus"Rhamphorhynchus""R." jessoni CambridgeshireWeymouth MemberIndeterminate non-monofenestratan pterosaur
Ichthyosaurs Genus Species Location Member Abundance Notes ImagesOphthalmosaurusO. icenicus Specimens consist of skulls, limb bones, and partial skeletonsA ophthalmosaurid ichthyosaur
Plesiosaurs
Genus Species Location Member Abundance Notes ImagesCryptoclidusC. eurymerusA cryptoclididC. richardsoniA cryptoclidid EardasaurusE. powelliA thalassophonean pliosauridLiopleurodon L. feroxA thalassophonean pliosauridL. pachydeirusA thalassophonean pliosaurid; probably a junior synonym of L.feroxMarmornectesM. candrewiA pliosauridMuraenosaurusM. leedsiA cryptoclididPachycostasaurusP. dawniiA pliosauridPeloneustesP. philarchusA thalassophonean pliosauridPicrocleidusP. beloclisA cryptoclididPliosaurusP. andrewsiA thalassophonean pliosaurid; represents a new genus distinct from PliosaurusSimolestesS. voraxA thalassophonean pliosauridTricleidusT. seeleyiA cryptoclidid
Pachycormiformes
Genus Species Location Member Abundance Notes Images Leedsichthys L. problematicus Giant filter feeding pachycormiformMartillichthysM. renwickaeFilter feeding pachyocormiformParaorthocormusP. tenuirostrisCarnivorous pachycormiform
Thalattosuchians
Genus Species Location Member Abundance Notes ImagesLemmysuchusL. obtusidensA teleosauroid belonging to the MachimosauridaeCharitomenosuchusC. leedsiA machimosaurid teleosauroidSteneosaurusS. edwardsiNow referred to Neosteneosaurus.S. durobrivensisJunior synonym of N. edwardsi.NeosteneosaurusN. edwardsiA machimosaurid teleosauroidMycterosuchusM. leedsiA teleosaurid teleosauroidMetriorhynchusM. superciliosus This species was referred to a new genus, Thalattosuchus.ThalattosuchusT. superciliosusA metriorhynchine metriorhynchidGracilineustesG. leedsiA metriorhynchine metriorhynchidSuchodusS. brachyrhynchusA geosaurine metriorhynchidS. durobrivensisA geosaurine metriorhynchidTyrannoneustesT. lythrodectikosA geosaurine metriorhynchid
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 List of fossil sites (with link directory) List of dinosaur-bearing rock formations Kimmeridge Clay London Clay Weald Clay
References
Bibliography
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