The Winton Formation is a Cretaceous geological formation in central-western Queensland, Australia. It is late Albian to early Turonian in age. The formation blankets large areas of central-western Queensland. It consists of sedimentary rocks such as sandstone, siltstone and claystone. The sediments that make up these rocks represent the remnants of the river plains that filled the basin left by the Eromanga Sea - an inland sea that covered large parts of Queensland and central Australia at least four times during the Early Cretaceous. Great meandering rivers, forest pools and swamps, creeks, lakes and coastal estuaries all left behind different types of sediment.

In some areas, the Winton Formation is over 400 metres thick. To bring with them such a huge amount of sediment, the rivers that flowed across these plains must have been comparable in size to the present-day Amazon or Mississippi rivers. As more and more sediment was brought in, the margins of the inland sea slowly contracted. By around 95 million years ago, the deposition was complete and the inland sea would never be seen again.

By virtue of its age and the environmental conditions under which the rocks it consists of were deposited, the Winton Formation represents one of the richest sources of dinosaur fossils anywhere in Australia.

Fauna

A fossil footprint-(ichnite), Wintonopus, found with two other dinosaur genera footprints at the Lark Quarry in Australia, c.f. Tyrannosauropus and Skartopus, have been found in the Winton Formation.

Dipnoi

Dipnoi of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Metaceratodus	M. bonei		Isolated tooth plates	Lungfish belonging to the extinct family Ceratodontidae
	M. ellioti
	M. wollastoni

Actinopterygii

Actinopterygii of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Cladocyclus	C. geddesi		Nearly complete skull and partial skeleton

Squamates

Squamates of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Varanoidea	Indeterminate		A damaged posterior trunk vertebra	Originally considered as dolichosaurid (cf. Coniasaurus), but reassigined

Crocodyliformes

Crocodyliformes of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Confractosuchus	C. sauroktonos		Nearly complete skeleton preserving a juvenile ornithopod in its abdomen
Isisfordia	I. duncani		Nearly complete skeleton and partial skull, referred complete skull

Dinosaurs

Ornithischians

Ornithischians of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Amblydactylus	A. gethingi	Lark Quarry.	Multiple footprints.
Ankylosauria	Indeterminate		Three isolated teeth from left and right dentary and right maxilla
Neornithischia	Indeterminate		Tooth
Ornithopoda	Indeterminate		Digested remains associated with the holotype of Confractosuchus
Ornithopoda	Undescribed		A nearly complete skull and mandible and at least three partial postcranial skeletons.	Small-bodied, recovered as part of "Elasmaria"
Wintonopus	W. latomorum	Snake Creek and Lark Quarry track site.	Footprints.	An ornithopod.

Sauropods

Sauropods of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Australotitan	A. cooperensis		A partial scapula, humeri, ulna, pubes, ischia, femora, presacral vertebral centrum fragments, and rib fragments.	A large diamantinasaurian sauropod that possesses a mosaic of features shared with titanosaurians with similar geographical and temporal range. Possibly a junior synonym of Diamantinasaurus.
Diamantinasaurus	D. matildae		A squamosal, quadrates, braincase, surangular, atlas intercentrum axis, cervical vertebrae, middle cervical neural arch, co-ossified sacral centra, cervical ribs, dorsal vertebrae, numerous dorsal ribs, fragmentary gastralia, coalesced sacral vertebrae, isolated sacral processes, scapula, coracoid, partial sternal plate, humeri, ulnae, radius, metacarpals I–V, manual phalanges, ilium, pubes, both ischia, femur, tibia, fibula, astragalus, and numerous fragments.	A diamantinasaurian sauropod known from partial cranial material.
Savannasaurus	S. elliottorum		Posterior cervical vertebrae, cervical ribs, dorsal vertebrae, dorsal ribs, sacral vertebrae with processes, partial caudal vertebrae, fragmentary scapula, coracoid, sternal plates, incomplete humeri, shattered ulna, radius, metacarpals I–V, metacarpal IV, manual phalanges, fragments of ilia, pubes, ischia, astragalus, metatarsal III, and associated fragments.	A wide-bodied sauropod that was well adapted to the wet, temperate floodplain environment it inhabited.
Sauropoda	Indeterminate		Poorly preserved remains associated with the holotype of Confractosuchus
Titanosauriformes	Undescribed		Partial skull, consisting of a braincase, quadrates, quadratojugals, a left squamosal, postorbitals, and several unprepared elements. associated with a hind limb
Wintonotitan	W. wattsi		A scapula, both humeri, both ulnae, both radii, near complete metacarpus preserving complete metacarpals II–V with proximal half of metacarpal I, fragmentary dorsal and sacral vertebrae and ribs, partial ilium, ischium, caudal vertebral series including anterior caudals, middle caudals, posterior caudals, proximal chevrons, and numerous unidentifiable fragments.	A titanosaur that is likely to be closely related to Australotitan, Diamantinasaurus and Savannasaurus.

Theropods

Theropods of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Australovenator	A. wintonensis		Dentaries, dorsal ribs and rib fragments, gastralial ribs and fragments, partial ilium, ulnae, radius, manus metacarpals, unguals, femur, tibiae, fibula, astragalus, metatarsals, pedal phalanges, humeri, radiale, distal carpal, and manual phalanxes.	A megaraptoran theropod known from postcranial and cranial material.
Megaraptoridae	Indeterminate		A partial skeleton, consisting of caudal vertebrae, metatarsals, a phalanx, and numerous unidentifiable fragments.

Pterosaurs

Pterosaurs of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Ferrodraco	F. lentoni		A partial premaxillae, maxillae and dentaries, partial frontal, mandibular articular region comprising the surangular, angular and articular, partial cervical vertebrae, partial scapulocoracoid, partial ulna, partial radius, proximal and distal carpals, metacarpal IV, proximal end of metacarpal IV, fragmentary non-wing manual phalanges, partial first wing phalanx (IV-1), and associated fragments.	The most complete pterosaur from Australia and the youngest known anhanguerian.

Flora

Flora of the Winton Formation
Taxa	Species	Presence	Material	Notes	Images
Angiospermae	Indeterminate		Leaf impressions, cuticle fragments	At least ten distinct types, belonging to both monocots and dicotyledons
Araucariaceae	Indeterminate		Leaves
Austrosequoia	A. wintonensis		Cones and leaved axes	A member of Cupressaceae
Cheirolepidiaceae	Four taxa		Dispersed cuticle
Emwadea	E. microcarpa		Seed cones	A member of Araucariaceae, more closely related to Agathis and Wollemia than Araucaria.
Equisetites	Indeterminate		Axes	Horsetail
Ginkgo	G. wintonensis, four other possible species		Leaf impressions (G. wintonensis) Dispersed cuticle	A gingophyte, genus extant.
Lovellea	L. wintonensis		Permineralised flower	A member of Laurales
Aff. Lygodium?	Indeterminate		Fern pinna
Marchantites	M. marguerita			Liverwort
Microphyllopteris	cf. M. gleichenoides		Frond fragment impression	A fern belonging to the family Gleicheniaceae
Otozamites	cf. O. bengalensis		Leaves	Member of Bennettitales
Phyllopteroides	P. macclymontae		Numerous pinnule impressions	A fern belonging to the family Osmundaceae
Pterostoma	Indeterminate		Leaves	A possible cycad
Ptilophyllum	Indeterminate		Leaves	Member of Bennettitales
Taeniopteris	Indeterminate		Leaf impression	A member of Pentoxylales, youngest record of the group in Australia
Tempskya	T. judithae		Permineralized false trunks	A tree fern

See also

• Lark Quarry Conservation Park
• Australian Age of Dinosaurs, which operates the Australian Age of Dinosaurs Museum of Natural History, and holds annual dinosaur digs in the Winton Formation
• List of dinosaur-bearing rock formations
• South Polar region of the Cretaceous