The Balfour Formation overlies the Middleton Formation of the Adelaide Subgroup and underlies the Katberg Formation of the lower Tarkastad Subgroup, all comprising the greater Beaufort Group. The Balfour Formation is composed of five members which are listed below (from oldest to youngest):
Oudeberg Member
Daggaboersnek Member
Ripplemead Member
Elandsberg Member
Palingkloof member
The rocks of the Balfour Formation also incorporate the entire Daptocephalus Assemblage Zone, the lowermost portion of the Lystrosaurus Assemblage Zone,[3] and the uppermost rocks of the Cistecephalus Assemblage Zone.[4] Up until the middle section of the Ripplemead Member, the Balfour Formation correlates with the near contemporaneous Teekloof Formation west of the 24 degrees from Beaufort West westwards, and to the Normadien Formation north of the Orange River. However, the Elandsberg and Palingkloof Members do not have any lateral correlates west of 24 degrees. This is either due to past erosion of the upper, unknown members of the Teekloof Formation or there was a sudden cessation of sedimentary deposition in the western section of the Karoo Basin.[5][6][7][8]
The sedimentary rocks of this formation are composed predominantly of alternating greenish-grey, bluish-grey, and grey-ish red mudstone that often contain siltstonelenses. The mudstones are very fine-grained, massive and exhibit blocky weathering. Claystone successions are also found which, along with the mudstones, frequently contain desiccation cracks, raindrop impressions, and calcareousnodules or concretions are found throughout. Rhythmites are also found. Sandstones are less common, but some notable units have been studied in the Balfour Formation. In the lowermost section of the Balfour is a sandstone-rich unit known as the Oudeberg Member. The sandstones in this unit are very fine-grained and are rich in feldspar. Another sandstone unit in the middle of the Balfour Formation is the Daggaboersnek Member which contains thin, tabular sandstones, and ripple structures are common.[9][10]
The presence of these rocks reveal much about the past environment that they were deposited in. The dominance of fine-grained mudstone and less common, fine-grained sandstones indicates that the rock sediments were deposited in a low-energy, fluvial environment, most likely one that had meandering rivers. At the time of sedimentary deposition, the Karoo retroarcforeland system was in an overfilled phase, and purely terrestrial sediments occupied the Karoo Basin at this time. As this formation includes the rocks of both the Cistecephalus, Daptocephalus,Lystrosaurus Assemblage Zones, the Balfour Formation preserves the geological record for the end Permian extinction event. This is important as the end Permian extinction event was the largest mass extinction event in the Earth's history. This was followed by one of the worst biotic crises, which is reflected in the sudden and drastic sedimentaryfacies changes in the overlying Katberg Formation.[11][12][13][14][15]
A partial skeleton including a complete skull and occluded mandible, the entirety of the precaudal axial column, partial scapulae, partial right pelvis, the right femur, and a disarticulated left humerus, ulna, radius, and tibia.
A complete skull and anterior half of skeleton in articulation, including vertebrae, ribs, pectoral girdle, partial left humerus, and complete right forelimb,
including terminal phalanges.
^Rubidge, B. S. (ed.) 1995b. Biostratigraphy of the Beaufort Group (Karoo Supergroup). South African Committee of Stratigraphy. Biostratigraphic Series 1. Pretoria, Council for Geoscience.
^Visser, J.N.J. and Dukas, B.A., 1979. Upward-fining fluviatile megacycles in the Beaufort Group north of Graaff-Reinet, Cape Province. Trans. Geol. Soc. S. Afr, 82(149), p.e154.
^Johnson, M.R.; Vuuren, C.J. Van; Visser, J.N.J.; Cole, D.I.; Wickens, H. De V.; Christie, A.D.M.; Roberts, D.L. (1997-01-01). "Chapter 12 The foreland karoo basin, south africa". Sedimentary Basins of the World. 3: 269–317. doi:10.1016/S1874-5997(97)80015-9. ISBN 978-0-444-82571-1. ISSN 1874-5997
^Katemaunzanga, David & Gunter, Cornelis Janse (2009-10-01). "Lithostratigraphy, Sedimentology, and Provenance of the Balfour Formation (Beaufort Group) in the Fort Beaufort–Alice Area, Eastern Cape Province, South Africa". Acta Geologica Sinica - English Edition. 83 (5): 902–916. Bibcode:2009AcGlS..83..902K. doi:10.1111/j.1755-6724.2009.00110.x. ISSN 1755-6724. S2CID 130345218
^Viglietti, P. A., Smith, R. M. H., Angielczyk, K. D., Kammerer, C. F., Fröbisch, J., Rubidge, B. S. (2016-01-01). "The Daptocephalus Assemblage Zone (Lopingian), South Africa: A proposed biostratigraphy based on a new compilation of stratigraphic ranges". Journal of African Earth Sciences. 113: 153–164. Bibcode:2016JAfES.113..153V. doi:10.1016/j.jafrearsci.2015.10.011. ISSN 1464-343X
^Abdala, Fernando & Gaetano, Leandro. (2019). A new, large cynodont from the Late Permian of the Karoo Basin, South Africa and its bearings in epicynodont phylogeny.. Zoological Journal of the Linnean Society. 10.1093/zoolinnean/zlz004.
^Lloyd, J. K.; Durand, F. (2025). "A new akidnognathid synapsid specimen from the Permian of Cradock, South Africa and the revision of Hewittia albanensis". Acta Palaeontologica Polonica. 70 (2): 339–355. doi:10.4202/app.01187.2024.