Arenig biostratigraphy and correlation in the Welsh Basin

Abstract
Recent work on the Arenig Series in the Welsh Basin is reviewed; it is now known to be far more complete and richly fossiliferous than has been supposed. Three regional stages, Moridunain, Whitlandian and Fennian, and seven trilobite-based biozones have been defined. Outstanding problems are highlighted, among which remains the definition of a stratotype for a base for the series, for which there appears to be only one feasible candidate in this area, in the Shelve inlier.