The Cistecephalus Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Late Permian in age.

The first fossils to be found in the Beaufort Group rocks that encompass the current eight biozones were discovered by Andrew Geddes Bain in 1856.

These formations all fall within the Adelaide Subgroup of the Beaufort Group, sediments of which were formed in a large retroarc foreland basin in southwestern Gondwana.

[18][19] The majority of the fossils in the biozone are found in these interchannel mudrock layers as animal remains that came to rest on the floodplains were quickly buried by alluvial sediments washed downstream.

In addition, Jurassic-aged dolerite sheet and dike intrusions into the Beaufort Group[21][22] have affected the uniformity in colour and texture of the biozone rocks in areas.

This includes the colour of the fossilized bones, which range from a smooth, white appearance to being nearly black depending on their proximity to the dolerite intrusions.

In addition species of Dicynodonts such as Endothiodon and Diictodon, Therocephalians,[27] Pareiasaurs, and rare occurrences of parareptiles such as Owenetta and Milleretta have been found in the upper zones.

An Endothiodon snout was discovered in the Rio do Rasto Formation in Brazil,[33][34] and Cistecephalus fossils have been found in Madumabisa Mudstone in Zambia.