The stratigraphic distribution of the Ordovician inarticulate brachiopod Orthisocrania divaricata (M'Coy) in the British Isles

Abstract

SummaryThe brachiopod Orthisocrania divaricata (M'Coy) is generally considered to be a fairly long-ranging form occurring in both the Caradoc and Ashgill Series. The latter age is based principally on records of its common occurrence from the Chair of Kildare, Ireland, but the species is not present in the Ashgill beds at this locality. It does occur there, however, in association with a fauna whose age is here judged to be Longvillian on the basis of its strong similarities to that of the Gelli-grin Calcareous Ashes. Examination of other records and occurrences suggests that this inarticulate is restricted to the Longvillian in the British Isles, and is therefore of some importance stratigraphically.