This is a list of fossiliferous stratigraphic units in Wales.
Group or Formation Period Notes Aber Mawr Shale Ordovician Afon Ffinnant Formation Ordovician Allt Ddu Formation Ordovician Aran Volcanic Group/Llyn y Gafr Formation Ordovician Bala Group/Rhiwlas Formation Ordovician Black Rock Limestone Carboniferous Blaencediw Formation Ordovician Bod Deiniol Formation Ordovician Bodeidda Mudstone Ordovician Bronydd Formation Silurian Bryn Siltstone Formation Ordovician Builth Volcanic Ordovician Camnant Mudstone Ordovician Carmarthen Formation Ordovician Carmarthen Group/Afon Ffinnant Formation Ordovician Carnedd Iago Formation Ordovician Crychan Formation Silurian Cwm Felin Boeth Formation Ordovician Cymerig Limestone Ordovician Cyrn Formation Ordovician Dolhir Formation Ordovician Dyserth Quarry Limestone Carboniferous Elton Beds Silurian Ffestiniog Flag Formation Cambrian Ffestiniog Flags Cambrian Foel Formation Carboniferous GelliFormation Ordovician Glyn Formation Ordovician Glyn Gower Formation Ordovician GraigFormation Ordovician Gronant Formation Carboniferous Haverford Formation Ordovician Haverford Mudstone Silurian Hells Mouth Grits Cambrian High Tor Limestone Carboniferous Hirnant Limestone Ordovician Hope Shale Ordovician Hughley Shale Silurian Hunts Bay Oolite Formation Carboniferous Leete Limestone Carboniferous Llanarmon Limestone Carboniferous Llandudno Pier Dolomite Formation Carboniferous Llanelly Formation Carboniferous Llanfallteg Formation Ordovician Llanfawr Mudstone Ordovician Llwyn Formation Carboniferous Lower Flaxley Beds Silurian Lower Longhope Beds Silurian Lower Old Red Sandstone Group/Downtonian Formation Silurian Ludlow Series Group/Whitcliffe Formation Silurian Mawddach Group/DolFormation Ordovician May Hill Sandstone Formation Silurian Mercia Mudstone Triassic Middle Elton Formation Silurian Milford Haven Formation Silurian Moel Hiraddug Limestone Carboniferous Nant Ffrancon Formation Ordovician Nant Hir Formation Ordovician Nant Hir Group/Derfel Limestone Ordovician Ogof Hen Formation Ordovician Onny Shale Ordovician PenFormation Silurian Plas Uchaf Formation Ordovician Pont y Fenni Formation Ordovician Pontyfenni Formation Ordovician Quartz Conglomerate Devonian Redhill Mudstone Ordovician Rhiwlas Limestone Formation Ordovician Senni bed Formation Devonian Senni Beds Devonian Sholeshook Limestone Ordovician Slade Mudstone Ordovician Spring Quarry Limestone Carboniferous St. Maughan's Formation Devonian Sully Beds Triassic Sutton Formation Jurassic Sutton stone Formation Jurassic Trefawr Formation Silurian Treiorwerth Formation Ordovician Ty Formation Silurian Upper Blaisdon Beds Silurian Upper Flaxley Beds Silurian Upper Longhope Beds Silurian Wenallt Formation Ordovician Wenlock Shale Silurian Wilsonia Shales Formation Silurian Woolhope Limestone Silurian
See also
Lists of fossiliferous stratigraphic units in Europe Lists of fossiliferous stratigraphic units in the United Kingdom
References