Extensive new collections from the Dinantian rocks of the British Isles confirm previously published opinions concerning the relationships between conodont distribution and facies. Conodonts from time-equivalent rocks, representative of numerous environments from the supratidal through the shelf into the open basin, indicate that Cavusgnathus and related genera are typical of near-shore environments whereas Siphonodella and Gnathodus characterise deeper water environments. This relationship is also demonstrated within vertical rock sequences through the Dinantian Subsystem, although the change is commonly accentuated by unconformable contacts. A limited number of Dinantian biofacies are recognised. Comparisons are made between conodont associations from the south and...