NEW FAUNAL DATA FROM THE HIGHEST ORDOVICIAN ROCKS AT POMEROY, COUNTY TYRONE, NORTHERN-IRELAND

Two new shelly faunas are reported from the Tirnaskea Formation in the Pomeroy inlier, County Tyrone. The middle part of the formation conta ins species of the brachiopods Dedzetina, Sericoidea, Proboscisambon a nd Protozyga? indicative of a deep-water biofacies and suggesting corr elation with the Rawtheyan Stage of the Ashgill Series although an Hir nantian age cannot be excluded. At higher levels within the unit Dyspr osorthis occurs with Eostropheodonta and the trilobite Mucronaspis, co nfirming an Hirnantian age for the upper part of the Tirnaskea Formati on. Deep water facies persisted at Pomeroy during the Hirnantian in co ntrast to the upward shallowing sequence at Girvan, SW Scotland, sugge sting a more offshore setting for the Irish deposits.