Ffair Fach Railway Cutting and River Section
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Geology & landscape
Geological Period: Ordovician
Description
Description The best locality with a complete section through the Lower Ordovician Ffairfach Group. This Group is made up of a 150 metre thick series of clastic sediments and volcanics with characteristic Llanvirn age shelly fossils. Above a regionally significant unconformity this sequence is overlain by rocks of the Llandeilo Series, here in its historic type area. This section, together with the Dynevor succession, constitutes the standard for the base of the Llandeilo. An internationally important locality in the historically famous Llandeilo type area, vital to future definition of this major time interval within the Ordovician Period.