Gwern-yfed-fach Quarry
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Geology & landscape
Geological Feature: Igneous Intrusion · Mining / Industrial: Quarry
Landscape processes: Volcanic / Igneous
Description
Description This small disused quarry exposes highly fossiliferous black flags and shales of the Llandeilo Caradoc Series, intruded by dolerite. The exposure is extremely fossiliferous, with twenty-five species of graptolites and nine species of trilobites known from the quarry. The graptolite Nemograptus gracilis and the trilobite Ogygiocaris buchi are particularly abundant, and these place the succession in the N. gracilis Biozone of the Llandeilo. The site is also the type locality for Trinucleus fimbriatus. The site is important in studying Llandeilo palaeoenvironments and faunal associations.