Weald Clay

Weald Clay Stratigraphic range: Hauterivian-Barremian, 136–125 Ma PreЄ Є O S D C P T J K Pg N
Type	Geological formation
Unit of	Wealden Group
Underlies	Atherfield Clay Formation
Overlies	Tunbridge Wells Sand Formation
Thickness	up to 460 m
Location
Region	England
Country	UK

Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock underlying areas of South East England. It is part of the Wealden Group of rocks.^[1] The clay is named after the Weald, an area of Sussex and Kent. It varies from orange and grey in colour and is used in brickmaking.

The un-weathered form is blue/grey, and the yellow/orange is the weathered form; they have quite different physical properties. Blue looks superficially like a soft slate, is quite dry and hard and will support the weight of buildings quite easily. Because it is quite impermeable, and so dry, it does not get broken by tree roots. It is typically found at 750mm down below a layer of yellow clay. Yellow, found on the surface, absorbs water quite readily so becomes very soft in the winter.

The two different types make quite different bricks.

Paleofauna

Dinosaurs reported from the Weald Clay
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Baryonyx	B. walkeri			Multiple partial skulls, one of which had an associated postcranial skeleton.[2]		Baryonyx
Horshamosaurus	H. rudgwickensis			"Vertebrae, partial fore and hindlimbs, osteoderms."[3]	An ankylosaur belonging to Polacanthinae. Originally named as a species of Polacanthus.[4]
Principiala[5]	P. rudgwickensis	Rudgwick Brickworks	Upper Weald Clay	Single partial fore-wing	An Ithonidae lacewing, the second in Principiala
Valdosaurus	V. canaliculatus[6]				An iguanodontian

See also

• Wealden
• Wealden Group
• Clay
• London Clay
• Oxford Clay
• List of dinosaur-bearing rock formations

Footnotes

1. "Wealden Clay Formation". The BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 14 December 2014.
2. "Table 4.1," in Weishampel, et al. (2004). Page 72.
3. "Table 17.1," in Weishampel, et al. (2004). Page 367.
4. Blows, W.T., 2015, British Polacanthid Dinosaurs – Observations on the History and Palaeontology of the UK Polacanthid Armoured Dinosaurs and their Relatives, Siri Scientific Press, 220 pp.
5. Jepson, JE; Makarkin, VN; Jarzembowski, E (2009). "New lacewings (Insecta: Neuroptera) from the Lower Cretaceous Wealden supergroup of Southern England". Cretaceous Research 30: 1325–1338. doi:10.1016/j.cretres.2009.07.012.
6. Galton, P.M., 2009, "Notes on Neocomian (Late Cretaceous) ornithopod dinosaurs from England - Hypsilophodon, Valdosaurus, "Camptosaurus", "Iguanodon" - and referred specimens from Romania and elsewhere", Revue de Paléobiologie 28(1): 211-273

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.