Ordovician and Silurian acritarch assemblages from the west Leinster and Slievenamon areas of southeast Ireland.

The Lower Palaeozoic sequences west of the Leinster Granite and in the Slievenamon Inlier of southeast Ireland have been palynologically re-investigated. Most of the productive samples yielded sufficient identifiable acritarchs for positive stratigraphical age determinations for several of the formations. The samples also include rare cryptospores, scolecodonts and tubular structures. Previous work in the area west of the Leinster Granite proposed an unbroken succession from Early Ordovician Ribband Group turbidites and volcanics passing up conformably to Early Ordovician to Late Silurian Kilcullen Group. The new palynological data clearly show that the Kilcullen Group in this area is entirely Silurian (Llandovery-early Wenlock) in age, also results obtained from the same group at Slievenamon confirm the previously reported Silurian age. Ordovician acritarchs found in the Kilcullen Group of both study areas are reworked and range in age from late Tremadoc to Llanvirn. The new data reveal a major stratigraphic break between the Ribband Group dated as Early and Middle Ordovician and the Silurian Kilcullen Group. This major break extends some hundreds of kms southwest to the Dingle Peninsula and possibly equates with a similar discontinuity in the Isle of Man to the northeast. This break would thus appear to be a major feature within the northwestern Avalonian margin sequence.

Systematic study and stratigraphic correlation of the Grandispora complex in the Famennian of northwest and eastern Europe.

In northwest and eastern Europe different miospore zonation schemes have been erected for the Famennian rocks, and correlation of these has proved problematical. However, in both regions of Europe Grandispora taxa are common elements in the respective Famennian spore successions, and it appears these taxa may have important intra-continental correlation potential. In order to assess this potential, a C.I.M.P. working group has undertaken a taxonomic study of the Grandispora complex in the Famennian of both regions. Representative material from Belarus, Poland, Germany, Belgium, France and Ireland has been exchanged, and then jointly studied, at four workshop meetings. A consensus of agreement has been reached on the morphological delineation and nomenclature of 13 species of Grandispora, and a description of each taxon is presented. One new species Grandispora tamarae is erected, and six new generic combinations are proposed. The stratigraphic range of each species in both regions is documented and calibrated with the respective conodont zonation schemes. It can be shown that many of the Grandispora species seem to have their first occurrence at similar stratigraphic levels. These new data allow detailed correlations of the Famennian miospore zonation schemes to be proposed.