BEAUFORT SERIES

Permo-Triassic rock strata of the Karoo System that overlie strata of the Ecca Series and underlie rocks of the Stormberg Series. The Beaufort is especially well developed and has been extensively studied in South Africa. It is primarily composed of sandstones, with some shales and coal lenticles (lens-shaped strata, thinner at the edges), and reaches a maximum thickness of about 3,000 m (10,000 feet). Of special importance is the fact that the Beaufort Series contains a rich and diverse reptilian fauna, characterized by an almost unparalleled mammallike therapsid assemblage. This assemblage has enabled the Beaufort to be further subdivided into six faunal zones, each of which is characterized by a particular and distinctive assemblage. The boundary between the Lower and Upper Beaufort Series is recognized as the boundary between the Permian and Triassic systems (i.e., about 245 million years ago). Although some therapsid groups did suffer reduction in the Triassic Period, faunal continuity is evident across the boundary, but close analysis discloses that there were critical shifts in faunal assemblages. The gorgonopsian therapsids (specialized sabre-toothed carnivores) became extinct at the end of the Permian, and the therocephalians and dicynodonts ("two-tuskers") were reduced; the more generalized cynodont therapsids, however, remained abundant. Over time, the typical reptilian Mesozoic assemblages, characterized by archosaurs and thecodonts, gradually became dominant.