Meidrim Road Section
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Geology & landscape
Rock Type: Limestone
Description
Description This site shows stratigraphically important sections through rocks of graptolitic facies of Llanvirn-Caradoc age. The site is the type locality of the local Mydrim Limestone of Caradoc age and of the Hendre Shales of Llandeilo age. The Didymograptus murchisoni Beds and the Asaphus Ash, both of Llanvirn age, and the Llandeilo Flags of Llandeilo age are also well exposed. The black graptolitic shales and siltstones of the Hendre Shales contain a rich fauna of trilobites and graptolites, including the trilobite Lloydolithus lloydi and the graptolites Diplograptus cf. vagus and Nemograptus gracilis. The faunal assemblage in the Hendre Shales at this site gives a good correlation with basal limestones and flags of the type sections at Llandeilo, where a shelly fauna predominates. The Meidrim site is important biostratigraphically as it shows that the N.gracilis Biozone has a range that extends from the Caradoc well into the Llandeilo.