The Telychian (Upper Llandovery) stratigraphy of the Buttington Brick Pit, Wales

Graptolites are recorded for the first time from the Telychian of Buttington Brick Pit, Wales. Five graptolitic horizons are present. The lowest two are turriculatus and crispus or griestoniensis biozone in age respectively. Between them are the earliest red/green beds in the sequence. The top three horizons may be assigned to the three Bohemian subzones, parapriodon, anguinus and geinitzi, of the spiralis biozone. This is the first British record of post-crenulata-pre-centrifugus biozone (basal Wenlock) graptolite faunas. Lithostratigraphically, the sequence is divided into 3 formations, the Cefn Formation at the base, the Tarannon Shales Formation from which the graptolites were collected, and, at the top, the Trewern Brook Mudstones Formation, known to be largely of Wenlock age. The bases of these formations are formally defined and a new member, the Butterley Mudstone Member, is erected to encompass the distinctive, lower part of the Trewern Brook Mudstones Formation.