Stratigraphic ranges of selected miospores in coal seams of Upper Coal Measures age in Oxfordshire and S.E. Warwickshire
Abstract. The extensive programme of boring recently undertaken by the National Coal Board to establish the limits of the concealed coalfield in Oxfordshire and southeast Warwickshire, has provided a unique sequence of high volatile bituminous coals from the upper part of the Upper Coal Measures suitable for spore analysis. The coals are mainly bright and the possible implications for the spore flora are briefly considered. The spores from the coals are characteristic of Westphalian D assemblages but the problem of recognising the base of the Westphalian D is discussed. It is concluded that the seams under investigation are all of Westphalian D age. Two new species, Vestispora burfordiensis and V. witneyensis are described. The occurrence of these species as well as Schopfites dimorphus and Punctatosporites granifer in Oxfordshire and in other British coalfields is reviewed. The ranges of these species provide the basis for recognising three new miospore assemblage zones to replace the former Thymospora obscura Assemblage Zone XI of Smith & Butterworth (1967). The base of the epibole of Thymospora pseudothiessenii is also well defined and is a useful biostratigraphic marker. Comparison is made with the zonal sub-division of the Desmoinesian series of the Illinois basin by Peppers (1985).