Deflexed didymograptids from the Lower Ordovician Skiddaw Group of northern England

摘要

The type species of Corymbograptus, Didymograptus v-fractus, is discussed and a neotype is proposed. The zonal graptolites Didymograptus varicosus and I). dcflexus, mainly from the Loweswater Formation of the Skiddaw Group succession, are discussed and illustrated as species of Baltograptus. Study of their proximal structure shows that the identification of D. varicosus in the Loweswater Formation is not correct. and the English specimens are here assigned to Baltograptus Jacksoni sp. nov.