Magnesian Conglomerate

Magnesian Conglomerate Stratigraphic range: Rhaetian ~208–202 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Lithology
Primary	Breccia
Other	Limestone
Location
Coordinates	51°30′N 2°36′W / 51.5°N 2.6°W / 51.5; -2.6Coordinates: 51°30′N 2°36′W / 51.5°N 2.6°W / 51.5; -2.6
Approximate paleocoordinates	35°54′N 0°48′E / 35.9°N 0.8°E / 35.9; 0.8
Region	South West England
Country	England
Extent	Bristol
Type section
Named by	Henry Riley & Samuel Stutchbury
Year defined	1836
Magnesian Conglomerate (England)

The Magnesian Conglomerate is a geological formation in Clifton, Bristol in England (originally Avon). It dates back to the Rhaetian stage of the Late Triassic,^[1][2] although it may be as old as the Norian stage of the Late Triassic and as young as the Hettangian stage of the Early Jurassic.^{[citation needed]} This formation was first discovered in autumn 1834 and was studied in 1836 by Henry Riley and Samuel Stutchbury.^[3]

The Avon Fissure Fill is probably the same formation as the Magnesian Conglomerate.

Vertebrate paleofauna[]

Archosaurs[]

Taxon	Species	Presence	Notes	Images
Agnosphitys[2][4]	A. cromhallensis[2][4]	Geographically present in Avon, England (now Bristol).[2]	Its remains include a left ilium (holotype) and a left maxilla, astragalus and humerus (referred specimen).[2]
Agrosaurus[5][2]	A. macgillivrayi[5][2]	Geographically present in Avon, England (now Bristol). Originally believed to have been found in Cape York Peninsula, Queensland (Australia).[2]	A tibia, a claw and some other fragments.[2]
Asylosaurus[2][6]	A. yalensis[2][6]	Geographically present in Avon, England (now Bristol).[2][7]	Dorsal vertebrae, ribs, gastralia, a shoulder girdle, humeri, a partial forearm, and a hand; additional bones from the neck, tail, pelvis, arm and legs that may represent the same individual.[6][2]
Palaeosaurus[2][6]	P. cylindrodon[2][6]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Two teeth (one destroyed in 1940).[2]
Rileyasuchus[2][8][9]	R. bristolensis[2][8][9]	Geographically present in Bristol.[2]	Two vertebrae and a humerus.[2]
Theropoda[2]	Indeterminate[2]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Indeterminate remains.[2]
Thecodontosaurus[2]	Indeterminate[2]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Indeterminate remains.[2]

Fish[]

• Lissodus minimus^[10]
• Rhomphaiodon minor^[10]
• ?Hybodontiformes indet.^[10]

See also[]

• List of dinosaur-bearing rock formations
• List of fossiliferous stratigraphic units in England

References[]

Bibliography[]

• Foffa, D.; D. I. Whiteside; P. A. Viegas, and M. J. Benton. 2014. Vertebrates from the Late Triassic Thecodontosaurus-bearing rocks of Durdham Down, Clifton (Bristol, UK). Proceedings of the Geologists' Association 125. 317–332.
• Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2
• Riley, H., and S. Stutchbury. 1836. A description of various fossil remains of three distinct saurian animals discovered in the autumn of 1834 in the Magnesian Conglomerate on Durdham Down near Bristol. Proceedings of the Geological Society 2. 397–399.

Further reading[]

• Riley, H. and Stutchbury, S. 1840. A description of various fossil remains of three distinct saurian animals recently discovered in the Magnesian Conglomerate near Bristol Transactions of the Geological Society of London 5, 349–357
• W. Buckland. 1824. Reliquiæ Diluvianæ; or, Observations on the Organic Remains Contained in Caves, Fissures, and Diluvial Gravel, and on Other Geological Phenomena, Attesting the Action of an Universal Deluge. Second Edition. John Murray, London 1-303

External links[]

• British Geological Survey Lexicon of Named Rock Units