Abstract. The age of the fossil flora found in the Kiltorcan Formation of Co. Kilkenny has been disputed for many years, with no datable miospore assemblage ever being extracted from the plant beds due to the preservation. New exposure on Kiltorcan Hill, and experimentation with palynological techniques has allowed the extraction of two miospore assemblages. The palynological data studied shows that the strata on Kiltorcan Hill straddles the Devonian/Carboniferous Boundary; A Devonian LE Miospore Biozone assemblage has been examined from a plant bed with Cyclostigma kiltorkense whilst a Carboniferous VI Miospore Biozone date was determined for a plant bed with Lepidodendropsis sp., and? Rhacophyton. The topmost occurrence of Cyclostigma kiltorkense is unknown but it is certainly very near to the Devonian/ Carboniferous Boundary. The use of Cyclostigma kiltorkense as an index fossil for the uppermost Devonian is therefore not precluded.