Group or Formation Period Notes Alston Group / Knipe Scar Limestone Carboniferous Alston Group / Potts Beck Limestone Carboniferous Ampthill Clay Jurassic Ancholme Group / Kimmeridge Clay Jurassic Ancholme Group / Oxford Clay Jurassic Ashfell Limestone Carboniferous Aymestry Limestone Formation Silurian Baggy Sandstones Formation Devonian Bala Group / Chatwell Flags Formation Ordovician Barton Formation Palaeogene Barton Beds Palaeogene Barton Clay Palaeogene Bee Low Limestones Carboniferous Belemnite Marls Jurassic Bembridge Limestone Palaeogene Bembridge Marls Palaeogene Bentham Grit Carboniferous Berkshire Oolite Formation Jurassic Black Rock Formation Carboniferous Blackdown Greensand Formation Cretaceous Blackheath Beds Palaeogene Blue Lias Formation Jurassic Bracklesham Formation Palaeogene Bracklesham Beds Palaeogene Bracklesham Group / Earnley Formation Palaeogene Bracklesham Group / Elmore Formation Palaeogene Bracklesham Group / Marsh Farm Formation Palaeogene Bracklesham Group / Selsey Formation Palaeogene Bracklesham Group / Wittering Formation Palaeogene Bringewood Beds Silurian Brockenhurst Beds Palaeogene Bromsgrove Sandstone Triassic Burwell Rock Formation Cretaceous Calcareous Grit Jurassic Carboniferous Limestone Carboniferous Carmarthen Formation Ordovician Carstone Formation Cretaceous Caton Shales Carboniferous Cauldon Low Conglomerate Formation Carboniferous Cauldon Low Limestone Carboniferous Cementstone Formation Carboniferous Chalk Formation Cretaceous Chalk Marl Formation Cretaceous Chalk Group / "Upper Chalk" Formation Cretaceous Chalk Group / Lower Chalk Formation Cretaceous Chalk Group / Lower Formation Cretaceous Charmouth Mudstone Formation Jurassic Chee Tor Limestone Carboniferous Cheney Longville Formation Ordovician Chillesford Clay Quaternary Claxby Ironstone Formation Cretaceous Clifton Down Limestone Carboniferous Cockhill Marine Band Carboniferous Colsterdale Marine Beds Carboniferous Coral Rag Formation Jurassic Corallian Oolite Formation Jurassic Corallian Group / Coral Rag Formation Jurassic Corallian Group / Kingston Formation Jurassic Coralline Crag Formation Neogene Coralline Oolite Formation Jurassic Cornbrash Formation Jurassic Cotswold Slate Formation Jurassic Crag Group / Norwich Crag Formation Quaternary Crag Group / Weybourne Crag Formation Creechbarrow Limestone Palaeogene Cromer Forest Bed Formation Cromer Knoll Formation Cromer Knoll Group / Spilsby Sandstone Cretaceous Crossdale Shales Carboniferous Crugan Mudstone Formation Ordovician Dartmouth Beds Devonian Denbury Crinoidal Limestone Devonian Dent Group / Keisley Limestone Ordovician Ditton Formation Devonian Downton Castle Sandstone Silurian Downton Sandstone Silurian Downton Group / Downton Castle Sandstone Silurian Downton Group / Rushall Formation Silurian Dufton Shales Ordovician Durlston Formation Cretaceous Duyfor Mudstone Ordovician East Ogwell Limestone Devonian Eggardon Grit Cretaceous Elton Beds Silurian Eyam Limestone Carboniferous Eyam Limestones Formation Carboniferous Farne Group / Scremerston Formation Carboniferous Forest Bed Formation Forest Hollow Beds Carboniferous Forest Marble Formation Jurassic Frome Clay Jurassic Fuller's Earth Formation Jurassic Gault Formation Cretaceous Glauconitic Marl Formation Cretaceous Great Oolite Formation Jurassic Great Oolite Group / Bath Oolite Formation Jurassic Great Oolite Group / Chipping Norton Limestone Jurassic Great Oolite Group / Cornbrash Formation Jurassic Great Oolite Group / Forest Marble Formation Jurassic Great Oolite Group / Hampen Marly Formation Jurassic Great Oolite Group / Sharp's Hill Formation Jurassic Great Oolite Group / Taynton Limestone Jurassic Great Oolite Group / White Limestone Jurassic Great Scar Limestone Group / Ashfell Formation Carboniferous Great Scar Limestone Group / Danny Bridge Formation Carboniferous Greta Grit Carboniferous Habberley Shale Ordovician Hambleton Oolite Formation Jurassic Hampen Marly Formation Jurassic Hartshill Formation Cambrian Harwich Formation Palaeogene Hastings Formation Cretaceous Hastings Beds Cretaceous Hastings Beds Group / Wadhurst Clay Cretaceous Hastings Group / Grinstead Clay Cretaceous Headon Formation Palaeogene Headon Hill Formation Palaeogene Hempstead Formation Palaeogene Hilton Plant Beds Permian Holderness Formation Hope Shale Ordovician Hopedale Limestones Formation Carboniferous Hotwells Formation Carboniferous Inferior Oolite Formation Jurassic Inferior Oolite Group / Chipping Norton Limestone Jurassic Inferior Oolite Group / Middle Inferior Oolite Formation Jurassic Inferior Oolite Group / Northampton Sands Jurassic Inferior Oolite Group / Upper Inferior Oolite Formation Jurassic Infracombe Slates Group / Combe Martin Slates Formation Devonian Insect Bed Formation Triassic Iron Sands Jurassic Junction Bed Formation Jurassic Keisley Formation Ordovician Kimmeridge Clay Jurassic Kimmeridge Formation Jurassic Kirkby Moor Flags Formation Silurian Ledbury Formation Silurian Leintwardine Formation Silurian Leintwardine Beds Silurian Lias Formation Jurassic, Triassic Lias Group / Beacon Limestone Formation Jurassic Lias Group / Blue Lias Formation Jurassic, Triassic Lias Group / Charmouth Mudstone Formation Jurassic Lias Group / Dyrham Formation Jurassic Lias Group / Marlstone Rock Formation Jurassic Lias Group / Scunthorpe Mudstone Formation Triassic Lias Group / Whitby Mudstone Formation Jurassic Lincolnshire Limestone Jurassic Llanfallteg Formation Ordovician London Clay Palaeogene Lower Borland Shales Carboniferous Lower Calcareous Grit Jurassic Lower Chalk Formation Cretaceous Lower Chalk Group / Abbott's Cliff Formation Cretaceous Lower Chalk Group / Cambridge Greensand Formation Cretaceous Lower Chalk Group / Chalk Marl Formation Cretaceous Lower Comley Formation Cambrian Lower Ditton Formation Devonian Lower Greensand Formation Cretaceous Lower Greensand Group / Atherfield Clay Cretaceous Lower Greensand Group / Faringdon Sand Formation Cretaceous Lower Greensand Group / Ferruginous Sands Cretaceous Lower Greensand Group / Folkestone Formation Cretaceous Lower Greensand Group / Hythe Formation Cretaceous Lower Greensand Group / Sandgate Formation Cretaceous Lower Greensand Group / Woburn Sand Formation Cretaceous Lower Hamstead Beds Palaeogene Lower Headon Beds Palaeogene Lower Limestone Group / Great Scar Limestone Carboniferous Lower Marl Formation Permian Ludlow Formation Silurian Lulworth Formation Cretaceous Lynton Slates Formation Devonian Magnesian Conglomerate Formation Triassic Malton Oolite Formation Jurassic Mammaliferous Crag Formation Marl Slate Formation Permian Mercia Mudstone Group / Blue Anchor Formation Triassic Mercia Mudstone Group / Keuper Waterstones Formation Triassic Mercia Mudstone Group / Tarporley Siltstone Formation Triassic Merevale Shales Ordovician Middle Calcareous Grit Jurassic Middle Chalk Formation Cretaceous Middle Headon Beds Palaeogene Middle Inferior Oolite Formation Jurassic Middle Limestone Group / Five Yard Limestone VI Formation Carboniferous Middle Limestone Group / Five Yard Limestone VI Cyclothem Formation Carboniferous Middle Limestone Group / Five Yard Limestone VIa Formation Carboniferous Middle Limestone Group / Five Yard Limestone VIa Cyclothem Formation Carboniferous Middle Limestone Group / Five Yard Limestone VIb Formation Carboniferous Middle Limestone Group / Gayle Limestone Cyclothem Formation Carboniferous Middle Limestone Group / Gayle Limestone II Formation Carboniferous Middle Limestone Group / Gayle Shale Carboniferous Middle Limestone Group / Hardrow Scar Limestone III Formation Carboniferous Middle Limestone Group / Hardrow Scar Limestone III Cyclothem Formation Carboniferous Middle Limestone Group / Hardrow Scar Limestone IIIa Formation Carboniferous Middle Limestone Group / Hardrow Scar Limestone IIIb Formation Carboniferous Middle Limestone Group / Hardrow Scar Limestone IIIc Formation Carboniferous Middle Limestone Group / Hawes Limestone I Formation Carboniferous Middle Limestone Group / Middle Limestone V Formation Carboniferous Middle Limestone Group / Middle Limestone V Cyclothem Formation Carboniferous Middle Limestone Group / Middle Limestone Va Formation Carboniferous Middle Limestone Group / Middle Limestone Va Cyclothem Formation Carboniferous Middle Limestone Group / Simonstone Limestone IV Formation Carboniferous Middle Limestone Group / Simonstone Limestone IV Cyclothem Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVa Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVa Cyclothem Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVb Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVb Cyclothem Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVc Formation Carboniferous Middle Limestone Group / Simonstone Limestone IVc Cyclothem Formation Carboniferous Middle Limestone Group / Three Yard Limestone VII Formation Carboniferous Middle Limestone Group / Three Yard Limestone VII Cyclothem Formation Carboniferous Middle Limestone Group / Underset Limestone VIII Formation Carboniferous Milldale Limestone Carboniferous Monsal Dale Limestones Formation Carboniferous Much Wenlock Formation Silurian Mytton Flag Formation Ordovician Mytton Flags and Tankerville Formation Ordovician Namurian Series Formation Carboniferous Norwich Crag Formation Quaternary Nothe Grits Formation Jurassic Ogof Hen Formation Ordovician Oldhaven Formation Palaeogene Oldhaven Beds Palaeogene Osborne Beds Palaeogene Osgodby Formation Jurassic Osmington Oolite Formation Jurassic Overton Formation Silurian Oxford Clay Jurassic Parrot Coal Formation Carboniferous Passage Beds Jurassic Penarth Group / Lilstock Formation Triassic Penarth Group / Westbury Formation Triassic Penarth Group / White Lias Formation Jurassic, Triassic Pendle Grit Carboniferous Penarth Group / Cotham Formation Triassic Penarth Group / Westbury Formation Triassic Petherwin Group / Baggy Formation Devonian Pilton Formation Devonian Pilton Shales Carboniferous, Devonian Pontyfenni Formation Ordovician Portland Formation Jurassic Portland Oolite Formation Jurassic Portland Group / Portland Stone Formation Jurassic Purbeck Formation Cretaceous, Jurassic Purbeck Group / Durlston Formation Cretaceous Purbeck Group / Lulworth Formation Cretaceous, Jurassic Ravenscar Formation Jurassic Ravenscar Group / Cloughton Formation Jurassic Ravenscar Group / Eller Beck Formation Jurassic Ravenscar Group / Lower Saltwick Formation Jurassic Ravenscar Group / Saltwick Formation Jurassic Ravenscar Group / Scalby Formation Jurassic Ravenscar Group / Scarborough Formation Jurassic Reading Beds Palaeogene Red Crag Formation Neogene Ringstead Coral Bed Formation Jurassic Roeburndale Formation Carboniferous Rutland Formation Jurassic Sabden Shale Carboniferous Saltwick Formation Jurassic Sandringham Sands Jurassic Sandringham Sandstone Cretaceous Sandsfoot Grit Jurassic Selborne Group / Gault Formation Cretaceous Selborne Group / Upper Greensand Formation Cretaceous Selsey Formation Palaeogene Sharp's Hill Formation Jurassic Sherwood Sandstone Group / Bromsgrove Sandstone Triassic Sherwood Sandstone Group / Otter Sandstone Formation Triassic Shunner Fell Formation Carboniferous Skegness Clay Cretaceous Solenopora Beds Carboniferous Solent Group / Bouldnor Formation Palaeogene Speeton Clay Cretaceous Spilsby Sandstone Cretaceous, Jurassic Stanford Formation Jurassic Stockdale Shales Silurian Suffolk Pebble Beds Palaeogene Tamar Group / Torquay Formation Devonian Tankerville Formation Ordovician Tarnbrook Wyre Marine Beds Carboniferous Temeside Shale Silurian Thanet Formation Palaeogene Blue Lias Formation Jurassic Torquay Limestone Devonian Trigonia clavellata Formation Jurassic Upnor Formation Palaeogene Upper Border Formation Carboniferous Upper Bowland Shales Carboniferous Upper Calcareous Grit Jurassic Upper Chalk Formation Cretaceou