Rolling Downs Group

The Rolling Downs Group is a stratigraphic group present in the Eromanga and Surat Basins in the northwestern to southwestern parts of 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 Inland 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
~127–90 Ma
TypeGroup
Sub-units
  • Wilgunya Subgroup
  • Bellinger Sandstone
  • Bulldog Shale
  • Coorikiana Sandstone
  • Oodnadatta Formation
UnderliesQuaternary Lake Eyre Basin sediments
OverliesCadna-Owie Formation, Bungil Formation
Thicknessup to 1,200 m (3,900 ft)
Lithology
PrimaryMudstone, siltstone, sandstone
OtherLimestone, claystone
Location
Coordinates22.6°S 143.0°E / -22.6; 143.0
Region New South Wales
 Queensland
 South Australia
Country Australia
ExtentEromanga & Surat Basins

References
  1. "Rolling Downs Group". Australian Stratigraphic Units Database. Geoscience Australia and Australian Stratigraphy Commission. Retrieved 20 August 2018.
  2. Thulborn, Tony; Turner, Susan (2003-05-07). "The last dicynodont: an Australian Cretaceous relict". Proceedings of the Royal Society of London B: Biological Sciences. 270 (1518): 985–993. doi:10.1098/rspb.2002.2296. ISSN 0962-8452. PMC 1691326. PMID 12803915.
  3. Knutsen, Espen M.; Oerlemans, Emma (September 2019). "The last dicynodont? Re-assessing the taxonomic and temporal relationships of a contentious Australian fossil". Gondwana Research. 77: 184–203. doi:10.1016/j.gr.2019.07.011.
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