The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup

Karoo Supergroup

The Karoo Supergroup is the largest stratigraphic unit in Southern Africa, covering almost two thirds of the present land surface, including central Cape Province, almost all of Orange Free State, western Natal, much of south-east Transvaal, Zambia, Zimbabwe and Malawi...

 of geological strata in Southern Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

. It follows conformably after the Ecca Group

Ecca Group

The Ecca Group is the name given to the sedimentary geological formations found in Karoo Basin region of Southern Africa. It consists mainly of shales and sandstones, laid down in the sandy shorelines of swamplands, during the Permian Period....

 and consists essentially of sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

s and shale

Shale

Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...

s, deposited in the Karoo Basin from the Middle Permian to the early part of the Middle Triassic

Anisian

In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 245 million years ago until 237 million years ago, approximately...

 periods.

In the Eastern Cape Province the Karoo Basin fill commenced with the deposition of the Dwyka Group

Dwyka Group

The Dwyka Group includes the sedimentary geological formations found in Karoo Basin region of Southern Africa. In the Eastern Cape Province the Karoo Basin fill commenced with the deposition of the Dwyka Group, followed by the Ecca Group, the Beaufort Group, the Molteno, Elliot, and Clarens...

, followed by the Ecca Group, the Beaufort Group, the Molteno

Molteno Formation

The Molteno Formation is a palaeontological formation of the Stormberg Group, located in the main Karoo Basin, South Africa. It dates to the Upper Triassic period and is rich in fossils....

, Elliot

Elliot Formation

The Elliot Formation is a geological formation dating to roughly 210 to 190 million years ago and covering the Norian to Sinemurian stages. The Elliot Formation is found in South Africa and Lesotho and is a member of the Stormberg Group. It consists mainly of limestone, sandstone, and mudstone...

, and Clarens

Clarens Formation

The Clarens Formation is a prominent fossil site in the Tuli Basin, in the KwaZulu-Natal region of South Africa.-Fauna of the Clarens Formation:Unidentified dinosaur eggs have been recovered from the formation.-Bony fish:-Dinosaurs:-Synapsids:...

 formations of the Stormberg Group

Stormberg Group

The Stormberg Group is the name given to the sedimentary geological formations found in Karoo Basin region of Southern Africa, immediately above the Beaufort Group...

 and the igneous Drakensberg Group. The basin followed the typical evolution of foreland basins, with the Ecca Group representing the ‘flysch

Flysch

Flysch is a sequence of sedimentary rocks that is deposited in a deep marine facies in the foreland basin of a developing orogen. Flysch is typically deposited during an early stage of the orogenesis. When the orogen evolves the foreland basin becomes shallower and molasse is deposited on top of...

’ component and the Beaufort Group, the overlying Molteno and Elliot Formations representing the ‘molasse

Molasse

The term "molasse" refers to the sandstones, shales and conglomerates formed as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse is deposited in a foreland basin, especially on top of flysch, for example that left from the rising Alps, or erosion in the Himalaya...

’-fluvial type sediments.

Deposits in this group include (in order of deposition):

• Lower Adelaide Subgroup comprising:
• Koonap Formation: Transitional brackish lacustrine to fluvial. Greenish-grey sandstones grading upwards into fine-grained siltstones and mudstones.
• Middleton Formation: Semi-arid climate supported a lush flora and fauna that thrived along meander belts and semi-permanent lakes. Cyclic deposits of lenticular sandstone bodies grading into greenish-grey mudstone. The thickest formation in this succession, constituting 37% of the Beaufort Group and 47% of the Adelaide Subgroup. The formation has lenses of red mudstone which are likely to have been deposited in a sub-aerial fluvial environment.
• Balfour Formation: The upper part of the Adelaide Subgroup and part of what was called lower to middle Beaufort.
• Upper Tarkastad Subgroup comprising:
• Katberg Formation: Arenaceous deposits of red and olive-yellow mudstones. Deposited in a braided fluvial system.
• Burgersdorp Formation: Deposited in a low-sinuosity fluvial system.

Paleontology

Fossils of tetrapod

Tetrapod

Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...

s, especially therapsids, are common, and the vertebrate

Vertebrate paleontology

Vertebrate paleontology is a large subfield to paleontology seeking to discover the behavior, reproduction and appearance of extinct animals with vertebrae or a notochord, through the study of their fossilized remains...

 biostratigraphy

Biostratigraphy

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period...

 has been mapped out in detail, beginning with the work of Robert Broom

Robert Broom

Professor Robert Broom was a Scottish South African doctor and paleontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow...

 at the start of the 20th century and developed and revised a number of times since. Currently eight faunal zones

Biochron

A Biochron is the length of time represented by a biostratigraphic zone. Biochrons are named after characteristic fossil organisms or taxa that characterise that interval in time.-References:...

 are recognised, tracing the development of terrestrial life through the Permo

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

-Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

, and named after a characteristic genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 that serves as an index fossil

Index fossil

Index fossils are fossils used to define and identify geologic periods . They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil...

.

In order the assemblage zones are:

• Cynognathus Assemblage Zone
  Cynognathus Assemblage Zone
  The Cynognathus Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Cynognathus, a genus of eucynodontian mammal-like reptile, whose fossils have been found in that structure....
  
    (Youngest)
• Lystrosaurus Assemblage Zone
  Lystrosaurus Assemblage Zone
  The Lystrosaurus Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Lystrosaurus, a genus of mammal-like reptile, a dominant life form of the Early Triassic Period, whose fossils have been found in that structure....
  
  
• Dicynodon Assemblage Zone
  Dicynodon Assemblage Zone
  The Dicynodon Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Dicynodon, a genus of mammal-like reptile, that flourished in the Permian Period and whose fossils have been found in that structure....
  
  
• Cistecephalus Assemblage Zone
  Cistecephalus Assemblage Zone
  The Cistecephalus Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Cistecephalus, a genus of small burrowing, mole-like reptile, whose fossils have been found in that structure....
  
  
• Tropidostoma Assemblage Zone
  Tropidostoma Assemblage Zone
  The Tropidostoma Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Tropidostoma, a genus of dicynodont mammal-like reptile, whose fossils have been found in that structure....
  
  
• Pristerognathus Assemblage Zone
  Pristerognathus Assemblage Zone
  The Pristerognathus Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Pristerognathus, a genus of Therocephalian mammal-like reptile, whose fossils have been found in that structure....
  
  
• Tapinocephalus Assemblage Zone
  Tapinocephalus Assemblage Zone
  The Tapinocephalus Assemblage Zone is a geological stratum and is the thickest faunal zone of the Beaufort Group, in which has been found a rich variety of early therapsids. The name refers to Tapinocephalus, a genus of large herbivorous dinocephalian synapsids that lived during the Middle Permian...
  
  
• Eodicynodon Assemblage Zone
  Eodicynodon Assemblage Zone
  The Eodicynodon Assemblage Zone is a geological stratum and a faunal zone of the Beaufort Group, of the South African Karoo. The name refers to Eodicynodon, a small herbivore and the earliest genus of dicynodont mammal-like reptile, whose fossils have been found in that structure.Eodicynodon was a...
  
    (Oldest)

The Beaufort Group deposits also yield numerous plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 and insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

fossils.