The Carboniferous basins of Britain and Ireland were part of a shallow epicontinental seaway. Widespread shallow- and marginal-marine conditions during the Asbian and Brigantian are recorded by mixed carbonate and siliciclastic deposits across northern Britain. Further south, carbonate successions developed on the platforms and shelves of England, Wales, and southern Ireland. Distinctive changes in the stacking pattern of the cycles defined from these successions at different locations suggest regional transgressions in the Asbian during a period of high global temperatures. In the mid-Brigantian, a marine transgression reduced deposition on the carbonate platforms and flooded the Midland Valley of Scotland, connecting previously separate subbasins. During the latest Mississippian (Namurian), the first extensive Southern Hemisphere glacigenic deposits broadly coincide with a positive shift in the carbon and oxygen stable isotope record and a transition to a humid climate in paleo-tropical latitudes. At this time across Britain and Ireland, siliciclastic fluvial, deltaic, and deep-water deposition dominated, and extensive peat mires developed in Scotland. Large-scale multistory fluvial systems (several tens of kilometers in width and tens of meters in thickness) incised into marine and deltaic deposits during periods of low eustatic sea level, and widespread marine bands are interpreted as eustatic sealevel rises. During the Westphalian, extensive peat mires developed on low-gradient waterlogged depositional plains. The presence of several widespread Westphalian marine bands suggests that significant eustatic rises led to extensive transgressions of this largely nonmarine environment. In the Asbian and Brigantian, eustatic sea-level changes were probably of lower magnitude during a period of higher global temperatures. During the early Namurian, the shift to a much cooler global climate provided a mechanism for generating higher-magnitude and higher-frequency eustatic changes as ice sheets waxed and waned.

Standing lycopsid trees occur at 60 or more horizons within the 1425-m-thick coal-bearing interval of the classic Carboniferous section at Joggins, with one of the most consistently productive intervals occurring between Coals 29 (Fundy seam) and 32 of Logan (1845) . Erect lepidodendrid trees, invariably rooted within an organic-rich substrate, are best preserved when entombed by heterolithic sandstone/mudstone units on the order of 3–4 m thick, inferred to represent the recurring overtopping of distributary channels of similar thickness. The setting of these forests and associated sediments is interpreted as a disturbance-prone interdistributary wetland system. The heterogeneity and disturbance inherent to this dynamic sedimentary environment are in accord with the floral record of the fossil forests and interpretation of the peat-forming wetlands as topogenous, rheotrophic forest swamps. Candidates for the erect, Stigmaria -bearing trees, which range in diameter (dbh) from 25 to 50 cm, are found in prostrate compressions and represent a broad range of ecological preferences amongst the Lycopsida. This record, which is not significantly time averaged, closely parallels the megaspore record from thin peaty soils in which they are rooted, but differs significantly from the miospore record in studies of other, thicker coals. Dominant megaspores are Tuberculatisporites mamillarus and Cystosporites diabolicus , derived from Sigillaria and Diaphorodendron / Lepidodendron respectively. Intervening beds preserve a record of an extra-mire flora composed in the main of seed-bearing pteridosperms and gymnosperms (and ?progymnosperms). Reproductive adaptation to disturbance appears to have played a key role in ecological partitioning of plant communities within these wetlands. Burial of lycopsid trees by onset of heterolithic deposition resulted in the demise of entire forest stands. Disturbancetolerant Calamites regenerated in the episodically accruing sediment around the dead and dying lycopsid stands, a succession identified here as typical of Euramerican fossil forests. Rapid, ongoing subsidence of the basin accommodated the submergence of the fossil forests, and abiotic disturbance inherent to the seasonal climate facilitated their episodic entombment. Disturbance is inferred to have been mediated by short-term (?seasonal) precipitation flux as suggested by the heterolithic strata and in the record of charred lycopsid trees, recording wildfire most probably ignited by lightning. Within this fossil forest interval is found a glimpse of animal life within the wetland ecosystem beyond the confines of the tree hollows, whence the bulk of the terrestrial faunal record of Joggins historically derives.