The Silurian Transgression of a Palaeoshoreline: The Area between Old Radnor and Presteigne, Welsh Borderlands

Abstract Quarries between Old Radnor and Presteigne, Welsh Borderlands, expose a Silurian nearshore succession, which onlaps rocky palaeotopography of the Neoproterozoic basement that had been uplifted along Church Stretton Fault Zone. The succession documents Aeronian to Sheinwoodian transgression an island or islands, with following sequence events: deposition shallow marine sandstones (Folly Sandstone Formation), regional uplift, preservation shoreline associated deposits (Dolyhir Rudite Member), limestones characterized by profusion coralline algae abundant remains reefs Nash Scar Limestone finally trilobitic silty mudstones (basal Coalbrookdale Formation). Facies analysis, carbon isotope (δ13Ccarb) values, stratigraphy, collections bryozoans, conodonts, thelodonts, trilobites have used here as means refining our stratigraphic understanding this unique succession. revised stratigraphy demonstrates many similarities adjoining Midland Platform wider world. Notable features include globally recognized early excursion sea-level changes global extent. As one best examples its kind, palaeoshoreline Presteigne acts depositional model for ancient shores worldwide.