Floral biostratigraphy of the upper silesian pennant measures of south wales

New information on the distribution of Upper Carboniferous fossil plants in South Wales has led the author to revise the positions of the chronostratigraphical boundaries in the Pennant Measures. The base of the Westphalian D is now placed in the upper Rhondda Beds. The middle Westphalian D floral change has been found to occur in two steps, one in the lower and one in the upper Hughes Beds. The Westphalian-Stephanian boundary is provisionally placed near the top of the Grovesend Beds.