P. F. Green, I. R. Duddy & R. J. Bray write: McCulloch (1994a) devoted much of his discussion of the paper by Holliday (1993) to criticism of papers by Green (1986) and Lewis et al. 1992, in which apatite fission track (AFT) data from northern England were interpreted in terms of regional cooling from palaeotemperatures around 100°C or above which began in the late Cretaceous to early Tertiary. McCulloch's stated purpose was to ‘highlight... the shortcomings in this interpretation' and to present an alternative interpretation in which some samples began to cool in the late Cretaceous to early Tertiary from palaeotemperatures greater than 110°C caused by local magmatic heating, while others began to cool as late as 30 Ma, from thermal effects associated with flow of hot fluids.
McCulloch (19946) raised similar criticisms of Green (1986) and Lewis et al. 1992 and we have prepared a detailed response to those criticisms for another publication. The main purpose of this comment is to emphasize that there is no basis for the suggestion that any samples from northern England began to cool as late as 30 Ma. This is true not only of the data presented by Green (1986) and Lewis et al. 1992 but also of a much larger dataset assembled in recent years from proprietary studies in the East Irish Sea Basin and surrounding regions. Rigorous interpretation of the AFT data from northwest England shows that, while data in individual samples are compatible with a range of timings for the