New occurrences of brachiopod and bivalve species from the arthurton group of south otago and southland, New Zealand with comments on structure and stratigraphy

Differences between Wood (1956) and Bishop (1965) over stratigraphy and structure in the Arthurton Group of South Otago are re-examined. It is considered that the pattern of folds mapped by Wood (1956) conforms better with available stratigraphic evidence than some of the structures proposed by Bishop (1965). Reference sections are proposed, for the Arthurton Group and Popotunoa Formation, and the latter is provisionally correlated with the Greville and Waiua formations of Nelson. The red beds stated by Bishop (1965) to be characteristic of the lower part of the Popotunoa Formation appear to come high in the formation. Three faunal zones are recognised in the area, correlated with the mid-Permian Kalabaghian, Chhidruan, and Urushtenian Substages of the world standard. Newly recognised, brachiopod species are described as Filiconcha auricula n.sp., Wairakiella sella n.sp., and Lamnaespina transennata n.gen. n.sp. (Family Spiriferinidae). Atomodesminae n. subfam. is proposed for Atomodesma and allies (? Family Inoceramidae). Several other species are recorded for the first time, including Atomodesma trechmanni (Marwick) in the upper AG 4 Formation. Auriculispina levis (Maxwell) is figured from Queensland