The Habberley Formation: youngest Tremadoc in the Welsh Borderlands

The Habberley Formation overlies the Shineton Shale Formation in the Shelve Inlier, Shropshire, and includes the youngest Tremadoc strata known from the Welsh Basin. It probably represents deposition during the interval cut out by the sub-Arenig unconformity in North Wales, and removed by the sub-Caradoc unconformity in the Wrekin district. There is no angular unconformity between Tremadoc and Arenig in the Shelve Inlier. The Habberley Formation is likely to correlate in part with the Hunnebergian Stage of Scandinavia. It was deposited probably in a largely stagnant basin, and records a shallowing-upwards sequence, prior to the Arenig transgression of the Stiperstones Quartzite. A sparse trilobite fauna proves the presence of theAngelina sedg vickiiBiozone, and a succeeding interval is characterized byAsaphelluscf.graffi. The trilobites are briefly described; they include the first undistorted material ofAngelina sedgwvickii. The brachiopodLingulella bella(Walcott), hitherto known only from eastern Newfoundland, is described by A. W. A. Rushton.