The age and affinities of the coral faunas from the lower Silurian rocks of the Charlestown Inlier, County Mayo, Ireland

The biostratigraphy and palaeonbiogeography of the coral faunas of the Lower Silurian succession in the Charlestown inlier, County Mayo, are discussed. Coral faunas are restricted in the fine sandstone lithology of the Cloonnamna Formation, but more common and highly diversified in the Uggool Limestone Member at the base of the formation. The fine sandstones contain the Palaeocyclus porpita — Favosites multipora association, widespread in similar lithologies in the circum-lapetus area where it is dated as of late Telychian (Lower Silurian) crenulata Biozone age. The Uggool Limestone Member contains 25 identifiable coral species together with 3 stromatoporoids, most known only from one to three specimens. The fauna indicates an early crenulata or possibly griestoniensis Biozone age and contains a mix of species of Laurentian and Avalonian affinities.