Article: Early Caradoc trilobites of eastern Ireland and their palaeogeographical significance

Twenty-five trilobite species belonging to twenty-three genera are recorded from the Caradoc Knockerk Formation of the Grangegeeth area, eastern Ireland. Arthrorhachis knockerkensis and Birmanitei salteri are new, while Barrandia sp. and Flexicalymene sp. possibly represent new species. The faunas occur predominantly in the lower parts of the Knockerk House Sandstones Member and younger Brickwork's Quarry Shales Member. The older fauna is of early Caradoc age and shows affinities with species from the Balclatchie and Lower Ardwell groups at Girvan. The younger trilobite fauna and associated graptolites are indicative of the Climacograptus peltifer Biozone (possibly Harnagian). The Laurentian/Scoto-Appalachian affinities of the Grangegeeth Caradoc faunas indicate that the Grangegeeth terrane was closest to Laurentia during the early Caradoc and that the final lapetus Suture line must lie to the south of the Grangegeeth terrane.