Zaphrentoid faunas occur in the Middle and Upper Viséan of Great Britain, but have not been adequately described and so are difficult to distinguish. Probably the most fossiliferous of such Upper Viséan faunas are those found in the D2–3 shales and grey limestones with chert which occur near the top of the Lower Carboniferous beds of Derbyshire. A characteristic form in these faunas is that usually assigned to Zaphrentis costata (McCoy), a species imperfectly known and inadequately described. In 1937 I collected such forms from Cawdor Quarry, Matlock Bridge, Derbyshire, with the intention of identifying and redescribing the species. Since then sections have been made from the lectotype: these sections, however, are imperfect and a specific description based on them by Hill (1940, p. 137) is necessarily incomplete. The specimens from Cawdor include one which is similar to Z. costata but which shows successive contractions of the corallum and a change from straight to waved and corrugated major septa, a phenomenon possibly due to “gerontism”.