The Beacon supergroup in the Allan Hills, central Victoria Land, Antarctica

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Abstract
Gently dipping Beacon strata of the Allan Hills fall in the upper Victoria Group, and consist of three formations: Permian, Glossopteris-bearing, Weller Coal Measures (110 m), containing the new Feistmantel Member, overlain by unfossiliferous pebbly Feather Sandstone (300 m), overlain by the Triassic, Dicroidium-bearing, coal-bearing, Lashly Formation (120 m). Neither top nor bottom of the sequence is seen. Fining-upwards alluvial cycles are present in the Weller and Lashly Formations, cross-bedding is present throughout, and the entire sequence is interpreted as having been deposited within a north-west flowing, meandering river system. The abundant carbon and lack of indicators of sub-aerial exposure point to a permanently saturated flood plain. The coal-bearing cyclothems of the Weller Coal Measures lose their finer divisions in an eastwards lateral transition, and the Coal Measures sensu stricto are thus lenticular. The lower two formations contain chiefly quartz, mica, and potash feldspar, and were derived from an acid plutonic and medium grade metamorphic terrain. The Lashly Formation contains low grade metamorphic and volcanic grains in addition to quartz, potash feldspar, and sodic feldspar. Heavy minerals of the lower two formations are dominated by garnet, tourmaline and zircon, and those of the Lashly Formation by apatite.