The plant record in the Dwyka and Ecca series (Permian) of the South-Western half of the Great Karroo Basin, South Africa
Bernard Price Institute for Palaeontological Research
There is a different relationship between the Dwyka and Ecca Series deposits in two geographically distinct areas of the Great Karroo Basin: in the south-west the White Band terminates the Upper Dwyka Shales, which conformably separate the Dwyka Tillite Stage from the Ecca Series, while in the north-east the Ecca Series, including the Coal Measures, rests directly on the Dwyka glacial deposits or pre- Karroo basement. The stratigraphic correlation of the sequence in the two areas is uncertain as the White Band and Coal Measures sandstones nowhere occur in the same section. The floras from the north-east have been widely described and illustrated; not so those from the south-west. The available information, part of it new, and representative illustrations are presented in this article. The material is too poor to merit formal taxonomic definition, but some general comparisons are possible. The genera Gangamopteris and Noeggerathiopsis are characteristic of the "Glossoopteris flora" in the Coal Measures in the north-east; they also occur in the glacial deposits in the south-west. This could be cited in support of isochronous accumulation of the sediments in question. Against this, there is some evidence indicating that Gangamopteris may persist above the White Band into the Ecca Series in the south-west. The advanced "Glossopteris floras" from the Upper Ecca Stages and overlying Beaufort Series in the two halves of the basin appear to be alike. A single incomplete' specimen of an "advanced" Glossopteris leaf has been found incongruously in the White Band equivalent in South West Africa. It is concluded that reliable correlation between the various Lower Karroo sequences cannot be based on the existing megaplant record.
Dwyka; Ecca; Permian; Karroo; South Africa