Fferam Uchaf

Site of Special Scientific Interest · 53.3522, -4.4639

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Gwynedd County

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Ordovician · Rock Type: Ironstone

Description

Description Fferam-uchaf is of special interest for its exposures of Llanvirn (Ordovician) rocks. The site comprises a number of small rock outcrops including a quarry on farmland approximately 1.5km north-east of Llanddeusant. This is the best locality for Llanvirn rocks in Anglesey, a Series that is otherwise poorly represented in north Wales. Fferam-uchaf shows small but stratigraphically important outcrops, with a diverse fauna, beneath the Caradoc Fferam Ironstone. The shales of the Llanvirn, the uppermost part of the Nantannog Formation, contain stratigraphically diagnostic graptolites together with a shelly fauna of bivalves, brachiopods and trilobites. This is an important site for an understanding of Lower Ordovician palaeogeography and the distribution of its faunas and sediments.