Rolling Downs Group

The Rolling Downs Group is a stratigraphic group present in the Eromanga and Surat Basins in eastern Australia,[1] which was deposited between the mid Barremian to early Turonian of the Cretaceous period. It primarily consists of nearshore shallow marine sediments deposited in the Eromanga Sea, though the uppermost and terminal members, the Winton Formation and the Griman Creek Formation represents freshwater deposits. It is notable for its fossil content including many dinosaurs and mammals, as well as opal. A relict species of dicynodont was suggested to have been found in these rocks,[2] but is more likely to be misidentified pieces of a Cenozoic marsupial from younger sediments.[3]

Rolling Downs Group
Stratigraphic range: Mid Barremian-Early Turonian ~
Type	Group
Sub-units	Griman Creek Formation Manuka Subgroup Winton Formation Mackunda Formation Wilgunya Subgroup Allaru Formation Toolebuc Formation Wallumbilla Formation Marree Subgroup Bellinger Sandstone Bulldog Shale Coorikiana Sandstone Oodnadatta Formation
Underlies	Quaternary Lake Eyre Basin sediments
Overlies	Cadna-Owie Formation, Bungil Formation
Thickness	up to 1,200 m (3,900 ft)
Lithology
Primary	Mudstone, siltstone, sandstone
Other	Limestone, claystone
Location
Coordinates	22.6°S 143.0°E / -22.6; 143.0
Region	New South Wales  Queensland  South Australia
Country	Australia
Extent	Eromanga & Surat Basins