The Cromer Forest-bed Formation, sometimes known as the Cromer Forest Bed, is a Pleistocene aged geological formation in Norfolk, England. It consists of river gravels, estuary and floodplain sediments predominantly silt, sand, and muds as well as peat along the coast of northern Norfolk. The formation records a number of glacial cycles, with deposition occurring in both relatively cold environments during glacial periods, as well during interglacial periods when the area had a temperate climate. The Cromer Forest Bed itself varies in age from about 2 to 0.5 million years ago, from the Early Pleistocene to early Middle Pleistocene, though the most fossiliferous strata, such as the West Runton Freshwater Bed date to towards the end of deposition during the early Middle Pleistocene. The fossiliferous West Runton Freshwater Bed is the type locality for the Cromerian Stage of the early Middle Pleistocene between 0.8 and 0.5 million years ago. Some fossils from the Cromer Forest Bed likely come from Early Pleistocene layers, though many finds are found out of stratigraphic context.
It is about thick and is exposed in cliff section near the village of West Runton.
Paleontology and paleoanthropology For over a century, this formation, named after the local town of Cromer, has been famous for its assemblage of fossil mammal remains, containing the diverse remains of numerous taxa.
The West Runton Mammoth, a largely complete skeleton of the steppe mammoth (Mammuthus trogontherii) is one of the best preserved finds found in the West Runton Freshwater Bed. The oldest human footprints outside Africa, the Happisburgh footprints as well as handaxes and bison bones with cut marks were also found in layers considered to belong to this deposit near Happisburgh, dated to around 1 million to 780,000 years ago.
Mammals
Carnivorans SpeciesLocalityNotesImagePanthera gombaszogensisWest Runon Freshwater BedOften called the European jaguar and posited to the ancestor of the living American jaguar (Panthera onca)Panthera fossilisWest Runon Freshwater Bed, PakefieldA close relative of the modern lion (Panthera leo), and one of the largest cats to have ever lived. Ancestor of the Late Pleistocene cave lion (Panthera spelaea). Older publications assigned remains of P. fossilis to P. leoFelis cf. lunensisWest Runon Freshwater BedA primitive member of the genus Felis, which includes the domestic cat and its close relativesUrsus sp.West Runon Freshwater BedPossibly represents brown bears (Ursus arctos) or members of the cave bear lineageUrsus deningeriBacton, PakefieldAncestor of the later cave bear (Ursus spelaea)Canis mosbachensisWest Runon Freshwater BedA smaller ancestor of the modern grey wolf (Canis lupus)Lynx sp.West Runon Freshwater BedA lynxCrocuta crocutaClosely related to living African spotted hyenas, have also been attributed to cave hyenas in older works.E.T. Newton On the occurrence of the cave hyaena in the "Forest Bed" at Corton Cliff, Suffolk The Geological Magazine, 10 (1883), pp. 433-435Homotherium latidensA lion-sized saber-toothed catPachycrocuta brevirostrisBacton, Overstrand A giant hyena, the largest everLutra simplicidensWest Runon Freshwater BedAn extinct otterPannonictis pliocaenicaAn extinct mustelid belonging to the subfamily IctonychinaeMartes martesCommonly known as the pine marten, species extantMustela nivalisCommonly known as the least weasel, species extantMustela ermineaCommonly known as the stoat, species extant
Ungulates SpeciesLocalityNotesImageCervus elaphusCommonly known as red deer, species extantPraemegaceros verticornisA giant deer belonging to the genus Praemegaceros. Sometimes referred to in historical publications as Megaloceros verticornisPraemegaceros dawkinsiA moderately sized deer.Megaloceros saviniA reindeer-sized deer speciesDama sp.An early indeterminate fallow deerCapreolus capreolusCommonly known as roe deer, species extantCervus rhenanusA smaller deer with three-pointed antlersEucladoceros ctenoides/tegulensisA giant deerEucladoceros tetracerosEucladoceros sedgwickiiCervalces latifronsA larger ancestor of the modern moose (Alces alces), one of the largest deer everHippopotamus antiquusA larger relative of the modern hippopotamus (Hippotamus amphibius)Bison schoetensackiA primitive bisonSus scrofaWest Runton Freshwater BedCommonly known as wild boar, species extantStephanorhinus hundsheimensisA rhinoceros belonging to the extinct genus StephanorhinusEquus cf. suessenbornensisA stenonine equineEquus cf. altidens
Proboscidea SpeciesLocalityNotesImageMammuthus trogontheriiWest Runton Freshwater BedCommonly known as the steppe mammoth, known from a mostly complete skeleton, the West Runton Mammoth collected from the West Runton Freshwater bed in 1990.Mammuthus meridionalisA more primitive mammoth chronologically earlier than M. trogontheriiPalaeoloxodon antiquusCommonly known as the straight-tusked elephant, a larger relative of African elephants
Eulipotyphla SpeciesLocalityNotesImageSorex runtonensisWest Runton Freshwater BedAn extinct shrew belonging the genus SorexSorex saviniSorex cf. minutusRemains closely resembling and possibly conspecific with the living pygmy shrew (Sorex minutus)Macroneomys brachygnathusA large extinct shrewNeomys newtoniAn extinct water shrew belonging to the genus NeomysDesmana sp. A desman related to the living Russian desman (Desmana moschata)Talpa minorAn extinct mole belonging to the genus TalpaTalpa europaeaCommonly known as the European mole, species extantErinaceus sp.A hedgehog, closely related to the living European hedgehog (Erinaceus europaeus)
Primates SpeciesLocalityNotesImageMacaca sylvanusWest Runton Freshwater BedCommonly known as the Barbary macaque. Though extinct in Europe (with the exception of Gibraltar), it remains extant in North Africa
Bats SpeciesLocalityNotesImageNyctalus noctulaWest Runton Freshwater BedKnown as the common noctule, species extant
Glires SpeciesLocalityNotesImageLepus sp.West Runton Freshwater BedA hareSciurus whiteiAn extinct squirrel belonging to the genus Sciurus, closely related to the living red squirrel (Sciurus vulgaris)Castor fiberCommonly known as the Eurasian beaver, species extantTrogontherium cuvieriAn extinct member of the beaver family Castoridae somewhat larger than living beaversCricetus runtonensisAn extinct hamster belonging to the genus Cricetus, closely related to the living European hamster (Cricetus cricetus). Some authors have attributed the remains to the living species.Cricetulus migratoriusCommonly known as the grey dwarf hamster, species extant though no longer living in BritainPliomys episcopalisA vole belonging to the extinct genus PliomysClethrionomys hintonianusAn extinct vole belonging to the genus Clethrionomys Mimomys saviniA vole belonging to the extinct genus Mimomys, related to living water voles (Arvicola)Microtus gregaloidesAn extinct vole belonging to the genus Microtus Microtus arvalidensMicrotus ratticepoidesApodemus sylvaticusCommonly known as the wood mouse, species extant
Birds A variety of birds are known from the Cromer Forest Bed. SpeciesLocalityNotesImagePhalacrocorax cf. carboWest Runton Freshwater BedRemains closely resembling and possibly conspecific with the living great cormorant (Phalacrocorax carbo)Cygnus sp.A swanAnser sp.A gooseAnatinae spp.Remains of several species of ducksGrus cf. Grus grusRemains closely resembling and possibly conspecific with the living common crane (Grus grus)cf. Gallinula chloropusRemains closely resembling and possibly conspecific with the living common moorhen (Gallinula chloropus)Turdus sp.A thrushSturnus sp. A starlingCorvidae indetA small bird belonging to the crow family"Gallus" europaeus Known from a coracoid, identification considered doubtful, and it has been suggested that "it is likely that it represents a living large galliform species."Aythya ferinaThe Common PochardNetta rufinaRed Crested PochardMelanitta nigraCommon ScoterPasseriformes indetA perching bird
Amphibians SpeciesLocalityNotesImageTriturus vulgarisWest Runton Freshwater BedCommonly known as the smooth newt, species extantTriturus sp. nov An extinct salamander belonging to the genus TriturusBufo bufoKnown as the common toad, species extantHyla arboreaCommonly known as the European tree frog, species extantRana arvalisCommonly known as the Moor frog, species extantPelophylax cf. ridibundusRemains closely related to the living marsh frog (Pelophylax ridibundus), recorded under the synonymous name Rana (ridibunda) sp.Rana temporariaKnown as the common frog, species extantRana cf. dalmatinaRemains closely resembling and possibly conspecific with the living agile frog (Rana dalmatina)
Reptiles SpeciesLocalityNotesImageAnguis fragilisWest Runton Freshwater BedCommonly known as the slow worm, species extantNatrix natrixCommonly known as the grass snake, species extantVipera berusCommonly known as the adder, species extant
Fish SpeciesLocalityNotesImageEsox luciusCommonly known as the Northern pike, species extantPerca fluviatilisCommonly known as the European perch, species extantTinca tincaCommonly known as the tench, species extantAbramis bjoerknaCommonly known as the white bream, species extantScardinius erythrophthalmusKnown as the common rudd, species extantRutilus rutilusKnown as the common roach, species extantLeuciscus idusCommonly known as the ide, species extantSqualius cephalusKnown as the common chub, species extantAnguilla anguillaCommonly known as the European eel, species extantGasterosteus aculeatusCommonly known as the three-spined stickleback, species extant
Insects A variety of beetles are known from the Cromer Forest Bed, including the West Runton Freshwater Bed, representing a temperate climate, and from Sidestrand, representing a cold glacial climate.
Flora Pollen and macrofossils from the West Runton Freshwater Bed indicates the presence of a variety of plants at the time of deposition, representing a forest and wetland environment with a temperate climate near to the North Sea coast.