Wallumbilla Formation

The Wallumbilla Formation is an Aptian geologic formation found in Australia. Plesiosaur and theropod remains are among the fossils that have been recovered from its strata.

Wallumbilla Formation
Stratigraphic range: Aptian-Albian, ~125–101 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Rolling Downs Group
Sub-units	Trimble Member, Ranmoor Member, Jones Valley Member, Doncaster Member, Coreena Member
Underlies	Toolebuc & Griman Creek Formations
Overlies	Cadna-Owie & Bungil Formations
Thickness	600 m (2,000 ft)
Lithology
Primary	Mudstone, siltstone
Other	Sandstone, limestone
Location
Coordinates	20.8°S 143.7°E / -20.8; 143.7
Approximate paleocoordinates	60.2°S 124.4°E / -60.2; 124.4
Region	New South Wales  Northern Territory  Queensland  South Australia
Country	Australia
Extent	Eromanga Basin
Wallumbilla Formation (Australia)

Description

The formation is present in the Northern Territory, Queensland, South Australia, and New South Wales. It is a sedimentary unit, principally made up of mudstone and siltstone, with calcareous concretions. Its maximum thickness is 600 metres. Its age is somewhere from Aptian to Albian, that is between 125 and 101 Mya. The formation is part of the Wilgunya Subgroup, which in turn is part of the Rolling Downs Group of the Eromanga and Surat Basins. The named beds are the Coreena, Doncaster, Jones Valley, Ranmoor, and Trimble Members.^[1]

Fossil content

Paleofauna of the Wallumbilla Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes	Images
Notopala Cotton, 1935	† Notopala albascopularis (Etheridge, 1902)	White Cliffs, New South Wales			The oldest freshwater snail in Australia.[2]
Kronosaurus	Indeterminate	White Cliffs			A pliosaur, also found in Queensland's Toolebuc Formation and Colombia's Paja Formation
Theropoda	Indeterminate
Platypterygius	Indeterminate				An ichthyosaur

See also

• Plesiosaur stratigraphic distribution
• South Polar region of the Cretaceous