Forest Marble Formation

The Forest Marble is a geological formation in England. Part of the Great Oolite Group, it dates to back to the late Bathonian stage of the Middle Jurassic.[2]

Forest Marble Formation
Stratigraphic range: Bathonian 168–166 Ma
↓
Forest Marble Formation exposed in Kirtlington Quarry, Oxfordshire
TypeGeological formation
Unit ofGreat Oolite Group
UnderliesCornbrash Formation
OverliesWhite Limestone Formation, Athelstan Oolite Formation, Chalfield Oolite Formation, Corsham Limestone Formation, Frome Clay
ThicknessUp to 5m thick in Buckinghamshire, 10 to 30m in Oxfordshire and Gloucestershire, 30 to about 50m in north Dorset, 30 to 75m in south Dorset[1]
Lithology
PrimaryMudstone, Limestone
OtherSiltstone, Sandstone
Location
RegionBedfordshire, Buckinghamshire, Oxfordshire, Dorset
Country UK
Type section
Named forWychwood Forest

Bradford Clay

Bradford Clay in geology, is a thin, rather inconstant bed of clay or marl situated in England at the base of the Forest Marble, the two together constituting the Bradfordian group in the Bathonian series of Jurassic rocks. The term "Bradford Clay" appears to have been first used by J. de. C. Sowerby in 1823 as an alternative for W. Smith's "Clay on Upper Oolite". The clay came into notice late in the 18th century on account of the local abundance of the crinoid Apiocrinus Parkinsoni. It takes its name from Bradford-on-Avon in Wiltshire, whence it is traceable southward to the Dorset coast and northward towards Cirencester.

It may be regarded as a local phase of the basement beds of the Forest Marble, from which it cannot be separated upon either stratigraphical or paleontological grounds. It is seldom more than 10 feet thick, and it contains, as a rule, a few irregular layers of limestone and calcareous sandstone. The lowest layer is often highly fossiliferous; some of the common forms being Arca minuta, Ostrea gregaria, Waldheimia digona, Terebratula coarctata and Cidaris bradfordensis.[3]

Lithology

The primary lithology of the formation typically consists of greenish grey silicate mudstone, with lenticular cross bedded limestone units deposited in a marine setting.

Dinosaurian fauna

Ornithischians
Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Ornithischians of the Forest Marble Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Alocodon[4]

Indeterminate[4]
Iguanodon

Hylaeosaurus[6]

Indeterminate[6]

 Dubious

Iguanodon[8]

Indeterminate[8]

 Dubious, probably indeterminate ornithiscian

Saurischians
Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Saurischians reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images

Bothriospondylus[9]

B. robustus[7]

"Dorsal vertebra."[10]

Reassigned to Marmarospondylus
Cetiosaurus

Indeterminate[5]

Cardiodon[7]

C. rugulosus[7]

Cetiosaurus[11]

C. oxoniensis
  • Oxfordshire

A cetiosaurid sauropod.

"Cetiosaurus"

C. glymptonensis[5]

"Caudal vertebrae."[12]

Marmarospondylus

Megalosaurus[13]

M. bucklandii[14]

Actually indeterminate theropod remains.[14]

Indeterminate[15]

Actually indeterminate theropod remains.[15]

Microvertebrate fauna

Despite the formation being nearly entirely marine, at several localities abundant remains of terrestrial microvertebrates are found, the primary locality being the Kirtlington Mammal Bed (designated 3p) near Kirtlington, Oxfordshire.[17] Another important locality is Watton Cliff in Dorset.[18]

Amphibians
Amphibians reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
Anoualerpeton A. priscus Kirtlington Albanerpetonid
Eodiscoglossus E. oxoniensis Kirtlington Frog, probably not closely related to type species of genus.
Eodiscoglossus
Marmorerpeton M. kermacki, M. freemani Kirtlington, Watton Cliff Salamander, possibly neotenic
Caudata Indeterminate Kirtlington 2 distinct taxa, one common one small, referred to as Kirtlington Salamander A and B, respectively

Turtles
Turtles reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
Pleurosternidae[19] Indeterminate Kirtlington Shell fragments

Choristoderes
Choristoderes reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
Cteniogenys Indeterminate Kirtlington

Lepidosauromorphs
Lepidosauromorphs reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
Balnealacerta B. silvestris Kirtlington
Bellairsia B. gracillis Kirtlington
Eophis E. underwoodi Kirtlington Stem-snake
Marmoretta M. oxoniensis Kirtlington Basal to Lepidosauria
Oxiella O. tenuis Kirtlington
Parviraptor cf. estesi Kirtlington Stem-snake
Saurillodon S. marmorensis Kirtlington
Rhynchocephalia Indeterminate Kirtlington

Crocodyliformes
Crocodyliformes reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
cf. Goniopholis Indeterminate Kirtlington
Goniopholis
cf. Theriosuchus Indeterminate Kirtlington

Mammaliamorphs
Mammaliamorphs reported from the Forest Marble Formation
Genus Species Location Stratigraphic position Material Notes Images
Amphitherium Indeterminate ?Kirtlington, Watton Cliff The first Mesozoic mammal to be described. Initially believed to be a marsupial. Close relative of Palaeoxonodon and Peramuridae.
Borealestes B. serendipitus Kirtlington, Watton Cliff molar fragments Docodonta
B. mussetti Kirtlington molar fragments
Eleutherodon E. oxfordensis Kirtlington, Watton Cliff Euharamiyida
Hahnotherium H. antiquum Kirtlington, Watton Cliff Multituberculate
Kermackodon K. multicuspis Kirtlington Multituberculate
Kirtlingtonia K. catenata Kirtlington Haramiyid
Krusatodon K. kirtlingtonensis Kirtlington
Millsodon M. superstes Kirtlington, Watton Cliff
Morganucodon M. tardus Watton Cliff Morganucodontidae
Morganucodon
Palaeoxonodon P. ooliticus Kirtlington, Watton Cliff
Paritatodon P. kermacki Kirtlington Shuotheriidae
Peraiocynodon P. major Kirtlington Docodontidae
Phascolotherium P. simpsoni Kirtlington, Watton Cliff Amphilestidae
Simpsonodon S. oxfordensis Kirtlington Docodonta
Shuotherium Indeterminate Kirtington Shuotheriidae
Stereognathus S. ooliticus Kirtlington, Watton Cliff Tritylodontidae
Stylidens S. hookeri Watton Cliff Morganucodontidae
Wareolestes W. rex Kirtlington Morganucodonta
Allotheria Indeterminate Kirtlington
Haramiyida Indeterminate Kirtlington
Peramuridae Indeterminate Watton Cliff

See also
  • List of dinosaur-bearing rock formations
  • Bradford Clay

Footnotes
  1. British Geological Survey. "Forest Marble Formation". BGS Lexicon of Named Rock Units. Retrieved 1 November 2018.
  2. Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 538–541. ISBN 0-520-24209-2.
  3.  One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Bradford Clay". Encyclopædia Britannica. 4 (11th ed.). Cambridge University Press. p. 372. This cites H. B. Woodward, "Jurassic Rocks of Britain," Mem. Geol. Survey, vol. iv. (1904).
  4. Listed as "cf. Alocodon sp." in "10.11 Oxfordshire, England; 6. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  5. "10.11 Oxfordshire, England; 6. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  6. Listed as "?Hylaeosaurus sp." in "10.13 Wiltshire, England; 3. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  7. "10.13 Wiltshire, England; 3. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  8. Listed as "?Iguanodon sp." in "10.11 Oxfordshire, England; 6. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  9. "10.11 Oxfordshire, England; 6. Forest Marble Formation" and "10.13 Wiltshire, England; 3. Forest Marble Formation," in Weishampel, et al. (2004). Page 540.
  10. "Table 13.1," in Weishampel, et al. (2004). Page 270.
  11. "10.11 Oxfordshire, England; 6. Forest Marble Formation," in Weishampel, et al. (2004). Page 538, 540.
  12. "Table 13.1," in Weishampel, et al. (2004). Page 265.
  13. Weishampel, et al. (2004). Pages 539-540.
  14. "10.3 Gloucestershire, England; 4. Forest Marble Formation," in Weishampel, et al. (2004). Page 538.
  15. "10.7 Dorset, England; 2. Forest Marble Formation" and "10.11 Oxfordshire, England; 6. Forest Marble Formation," in Weishampel, et al. (2004). Pages 539-540.
  16. "10.7 Dorset, England; 2. Forest Marble Formation," in Weishampel, et al. (2004). Page 539.
  17. "Kirtlington 3p (Mammal Bed)". Paleobiology Database. Retrieved 28 August 2018.
  18. "Watton Cliff (West Cliff), Dorset". Paleobiology Database. Retrieved 28 August 2018.
  19. SCHEYER, TORSTEN M.; ANQUETIN, JÉRÉMY (March 2008). "Bone histology of the Middle Jurassic turtle shell remains from Kirtlington, Oxfordshire, England". Lethaia. 41 (1): 85–96. doi:10.1111/j.1502-3931.2007.00044.x. ISSN 0024-1164.

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