New data on palynological boundaries within the Irish Dinantian

New palynological data are presented from the upper Tournaisian and lower Viséan rocks of central and northwest Ireland which provide further refinement of the miospore zonation scheme for the Irish and British Dinantian. The PC and CM Biozones have been located in several borehole cores, and the base of the CM Biozone is now recognised solely on the appearance of Schopfites claviger. Associated microfaunas indicate the PC-CM boundary is late Tournaisian (Tn3) in age. The overlying Pu Biozone is informally divided into two parts; a lower division containing rare Lycospora pusilla and an upper division with abundant representatives of that species. The TS Biozone has been recorded in several sections and cores across northwest Ireland, with the base of the biozone occurring close to the Arundian/Holkerian stage boundary. Recent palynological data from the Visean of the Midland Valley of Scotland indicate that the interval representing the TS Biozone is composed of igneous and/or coarse clastic sequences.