ABSTRACT
The Ordovician brachiopod faunas from terranes in the lapetus suture zone of Ireland have been revised, permitting a better characterisation of their generic composition, and emphasising their disparate positions during the Early Ordovician. Mid-Ordovician faunas signal the development of the Anglo-Welsh faunal province across the Leinster Terrane, and highlight the marginal situations of faunas from Bellew-stown and Grangegeeth. The Ashgill Foliomena fauna from Ballyvorgal in the Central Terrane enhances the similarity with coeval faunas from Oriel Brook in the Grangegeeth Terrane. Hirnantia brachiopod faunas existing across the entire lapetus suture zone are represented by assemblages at Kildare in the Leinster Terrane. Improved stratigraphic correlation, and refined discrimination of biogeographical affinity and flux within the lapetus Ocean system is possible. Rapid cross-latitudinal migration of these terranes during the Ordovician is indicated by their changing provincial faunal signals.
