Avon Fissure Fill

The Avon Fissure Fill, also known as the Bristol Fissure Fill or Tytherington Fissure Fill,^[1] is a fissure fill in Avon, England (now Bristol) which dates variously from the Norian and Rhaetian stages of the Late Triassic, or possibly as late as the Hettangian stage of the Early Jurassic.^[2] The fissure fill at Avon was a sinkhole formed by the dissolution of Lower Carboniferous limestones.^[1]

Avon Fissure Fill
Stratigraphic range: Norian-Hettangian, 216.5–199.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Underlies	Lower Carboniferous limestones
Location
Coordinates	51.5°N 2.6°W / 51.5; -2.6
Approximate paleocoordinates	35.9°N 0.8°E / 35.9; 0.8
Region	South West England
Country	England
Extent	Avon (now Bristol)
Type section
Named for	Avon county
Named by	Henry Riley & Samuel Stutchbury
Year defined	1836
Avon Fissure Fill (England)

It is paired with the nearby Magnesian Conglomerate; it may have been the same formation as the Magnesian Conglomerate.^[1]

Paleofauna

Taxon	Species	Presence	Notes	Images
Agnosphitys[2][3]	A. cromhallensis[2][3]	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[4][2]	A. macgillivrayi[4][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][5]	A. yalensis[2][5]	Geographically present in Avon, England (now Bristol).[2][6]	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.[5][2]
Chimaeriformes[7]	Indeterminate[7]	Geographically present in Bristol.[2]	Indeterminate remains.[7]
Clevosaurus[8]	C. hudsoni[8]	Geographically present in Gloucestershire.[2]	Partial cranial and post-cranial skeleton (holotype).[8]
Crinoidea[7]	Indeterminate[7]	Geographically present in Bristol.[2]	Reworked from older Carboniferous sediments (Friars Point Limestone Formation).[9]
Diphydontosaurus[7]	D. avonensis[7]	Geographically present in Bristol.[2]	Complete to near-complete specimens.[7]
Hybodontiformes?[10]	Indeterminate[10]	Geographically present in Bristol.[2]	Indeterminate remains.[10]
Gyrolepis[11]	Indeterminate[11]	Geographically present in Bristol.[2]	Indeterminate remains.[11]
Lissodus[10]	L. minimus[10]	Geographically present in Bristol.[2]	Teeth.[10]
Palaeosaurus[2][5]	P. cylindrodon[2][5]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Two teeth (one destroyed in 1940).[2]
Planocephalosaurus[12][13]	P. robinsonae[12][13]	Geographically present in Bristol.[2]	Skull (holotype).[12]
Rhomphaiodon[10]	R. minor[10]	Geographically present in Bristol.[2]	Teeth.[10]
Rileyasuchus[2][14][15]	R. bristolensis[2][14][15]	Geographically present in Bristol.[2]	Two vertebrae and a humerus.[2]
Terrestrisuchus?[10][7]	Indeterminate[10][7]	Geographically present in Bristol and South Wales.[2]	Indeterminate remains.[10][7]
Theropoda[2]	Indeterminate[2]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Indeterminate remains.[2] Possibly similar to Pendraig milnerae.[16]
Thecodontosaurus[2]	T. antiquus[2]	Geographically present in Avon, England (now Bristol) and Bristol.[2]	Partial cranial and postcranial remains (holotype is a lower jaw).[2]