Abstract Considerable progress has been made by international teams in refining the traditional ammonoid zonation that remains the backbone of Carboniferous stratigraphy. The Carboniferous ammonoid genozones, with a few gaps, are now recognized throughout the entire system in most successions worldwide. Refined collecting and documentation of occurrences in Western Europe, North Africa, the Urals, China and North America aimed to establish the first evolutionary occurrences, and facilitated correlation with foraminiferal and conodont scales for most of the Carboniferous. From ten to eleven ammonoid genozones are now recognized in the Mississippian, and eight to nine genozones in the Pennsylvanian. Of these, the established lower boundaries of the subsystems are reasonably well correlated with the ammonoid zonation, whereas correlations with the ratified foraminiferal-based lower boundary of the Visean and other stage boundaries, currently under discussion, need further research. Future success in the ammonoid geochronology will also depend on accurate identification and re-illustration of the type material, including material described by pioneers of ammonoid biostratigraphy.

Abstract To the south of the Mississippian platform carbonate successions of South Wales (Chapter 5) and Bristol, Mendips and Somerset (Chapter 6), Carboniferous rocks predominantly occur within the strongly deformed Culm crop of SW England. The Culm Basin has a broad graben architecture, with an inner graben (Central Devon Sub-basin) fianked by half-grabens (Bideford and Launceston sub-basins) (Fig. 14; Leveridge & Hartley 2006; Waters et al. 2009). The Bideford Sub-basin is bounded to the north by the Brushford Fault, the Central Devon Sub-basin by the Greencliff Fault and the Launceston Sub-basin by the Rusey Fault. To the north of the Brush-ford Fault is the northern margin of the Culm Basin. The Tavy Basin has limited development of Famennian-Tournaisian strata. The Laneast High separating the Tavy Basin and Launceston Sub-basin includes a Tournaisian to ?Visean succession (Yeolmbridge and Laneast Quartzite formations). Remnants of Carboniferous strata also occur in the South Devon Basin. In many areas there is no clear lithological break between the Tournaisian and the underlying Upper Devonian rocks, both of which are dominated by shallow-marine and deeper-water mudstones. The succession, commonly referred to as the Transition Series or Group (Dearman & Butcher 1959; Freshney et al. 1972), are assigned to the Exmoor Group in north Devon, the Hyner Mudstone and Trusham Mudstone formations of the eastern part of the Central Devon Sub-basin and the Tamar Group in south Devon.

Abstract Carboniferous conodont biostratigraphy comprises regional zonations that reflect the palaeogeographical distribution of taxa and distinct shallow-water and deep-water conodont biofacies. Some species have a global distribution and can effect high quality correlations. These taxa are incorporated into definitions of global Carboniferous chronostratigraphic units. A standard global Carboniferous zonation has not been developed. The lowermost Mississippian is zoned by Siphonodella species, excepet in shallow-water facies, where other polygnathids are used. Gnathodus species radiated during the Tournaisian and are used to define many Mississippian zones. A late Tournaisian maximum in diversity, characterized by short-lived genera, was followed by lower diversity faunas of Gnathodus species and carminate genera through the Visean and Serpukhovian. By the late Visean and Serpukhovian, Lochriea provides better biostratigraphic resolution. Shallow-water zonations based on Cavusgnathus and Mestognathus are difficult to correlate. An extinction event near the base of the Pennsylvanian was followed by the appearance of new gnathodid genera: Rhachistognathus , Declinognathodus , Neognathodus , Idiognathoides and Idiognathodus . By the middle of the Moscovian, few genera remained: Idiognathodus , Neognathodus and Swadelina. During the middle Kasimovian and Gzhelian, only Idiognathodus and Streptognathodus species were common. Near the end of the Gzhelian, a rediversification of Streptognathodus species extended into the Cisuralian.