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 PreꞒ Ꞓ O S D C P T J K Pg N ↓
Forest Marble Formation exposed in Kirtlington Quarry, Oxfordshire
Type	Geological formation
Unit of	Great Oolite Group
Underlies	Cornbrash Formation
Overlies	White Limestone Formation, Athelstan Oolite Formation, Chalfield Oolite Formation, Corsham Limestone Formation, Frome Clay
Thickness	Up 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
Primary	Mudstone, Limestone
Other	Siltstone, Sandstone
Location
Region	Bedfordshire, Buckinghamshire, Oxfordshire, Dorset
Country	UK
Type section
Named for	Wychwood 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]	Oxfordshire[5]				Iguanodon
Hylaeosaurus[6]	Indeterminate[6]	Wiltshire[7]			Dubious
Iguanodon[8]	Indeterminate[8]	Oxfordshire[5]			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]	Wiltshire[7]		"Dorsal vertebra."[10]	Reassigned to Marmarospondylus	Cetiosaurus
	Indeterminate[5]	Oxfordshire[5]
Cardiodon[7]	C. rugulosus[7]	Wiltshire[7]
Cetiosaurus[11]	C. oxoniensis	Oxfordshire			A cetiosaurid sauropod.
"Cetiosaurus"	C. glymptonensis[5]	Oxfordshire[5]		"Caudal vertebrae."[12]
Marmarospondylus
Megalosaurus[13]	M. bucklandii[14]	Gloucestershire[14]			Actually indeterminate theropod remains.[14]
	Indeterminate[15]	Dorset[16] Oxfordshire[5]			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.