PLEISTOCENE HISTORY OF THE BRITISH VERTEBRATE FAUNA

• 1 This review covers the Pleistocene history of British non-marine Pisces, Amphibia, Reptilia and especially Mammalia, which alone have a good fossil record. Aves are also briefly discussed.
• 2 The fossil material available is often inadequate for purposes of taxonomy and identification. Further problems arise because many groups of Mammalia have undergone rapid evolution during the Pleistocene.
• 3 In this paper the fossil record is related to the currently accepted stratigraphic table of the British Pleistocene (Shotton & West, 1969). Wherever possible, fossil records have been assigned to pollen assemblage zones. Throughout, emphasis is placed on the relationship between faunal history and vegetational history, as determined from fossil pollen and macroscopic plant remains.
• 4 Although fossils are relatively scarce in the fluviatile and lacustrine deposits of open sites, compared with the often rich cave assemblages, the stratigraphy of the former is usually much clearer and the sediments commonly contain pollen. It is difficult to correlate cave sequences with those of open sites.
• 5 It is important to take into account possible bias in a fossil assemblage according to its mode of accumulation, e.g. assemblages from occupation sites may represent only those animals which were hunted by man.
• 6 Lower Pleistocene vertebrates are rather poorly-known. The majority of fossils are from the marine Crags of East Anglia (Pre-Ludhamian to Pastonian) and a single cave assemblage of this age is known (Dove Holes). Few records can be related to particular stages, but a few finds from Easton Bavents are assigned to Antian and Baventian stages.
• 7 Early Middle Pleistocene vertebrates are represented mainly by the rich assemblages from the marine and fresh-water Weybourne Crag and Cromer Forest Bed Series (Baventian to Early Anglian) of Norfolk and Suffolk. The East Runton fauna appears to be of pre-Cromerian (?Pastonian) age. A good fauna is known from the type Cromerian deposits at West Runton (zone Cr 11). A few records are available for zone ?Cr III and one for the Early Anglian. The assemblages from other localities appear to represent more than one stage at each site, e.g. the so-called ‘Bacton Forest Bed’ fauna is composite, including both Cromerian and ?Pastonian taxa. Outside East Anglia one open site (Sugworth) and one cave fauna (Westbury) of probable Cromerian age are known.
• 8 Many of the fossils found in lacustrine and river-terrace deposits of the Middle and Upper Pleistocene glacial-interglacial succession (Anglian to present day) can be assigned to particular stages, zones or even subzones. Cave assemblages rarely predate the Ipswichian. No pre-Devensian records are available for either Scotland or Ireland. The Anglian fauna is very poorly known. The Hoxnian is represented principally by the Clacton (zone Ho IIb) and Swanscombe faunas. The Baker's Hole deposit, the basal gravels of the Summertown-Radley Terrace and the Glutton and Bear Strata in Tornewton Cave have yielded faunas of probable Wolstonian age. The early Ipswichian is poorly represented (Selsey), many fossils are known from zone Ip Iib (e.g. Trafalgar square, Swanton Morley, Aveley), there are a few records from early zone Ip III (Aveley, Swanton Morley) and fairly good faunas from zone Ip III/IV (Histon Road, Stutton). Several open and cave-site faunas resemble those of zones Ip II and Ip III and the assemblages from Ilford, Brundon, etc., appear to date from the end of this interglacial. The Early Devensian is represented by the Wretton fauna and probably by some cave faunas. Middle Devensian faunas are fairly well known (e.g. Upton Warren) and there are a number of records for the Late-Devensian (Ballybetagh, High Furlong, Nazeing). Many cave faunas date from the Middle or Late Devensian. Good faunas are available from the early Flandrian, zone F1 I (e.g. Star Carr). The present-day native fauna (zone F1 111) is also discussed.
• 9 The main faunal characteristics for each subdivision of the Pleistocene are summarized in the Conclusions. There is a major faunal change between the predominantly Tertiary fauna of the Red Crag Nodule Bed (Probably Pre-Ludhamian and older) and that of the Red Crag (Pre-Ludhamian and Ludhamian). There appears to have been comparatively little change in fauna through the rest of the Lower Pleistocene but the more intense climatic fluctuations of the Middle and Upper Pleistocene were accompanied by rapid faunal change and the appearance of characteristic ‘steppe-tundra’ faunas in the Wolstonian and Devensian cold stages. The Late-Devensian and Flandrian faunas are impoverished in comparison to earlier stages. This may be partly due to the activities of man as well as climatic and vegetational changes.
• 10 There is usually good agreement between fauna and vegetational conditions when these can be compared, but a few taxa (e.g. Cricetus cricetus, Equus) have clearly changed their ecological requirements during the Pleistocene. Changes of fauna in response to vegetational changes within interglacials are known from the Hoxnian and especially the Ipswichian. The ‘steppe-tundra’ vegetation of cold stages was accompanied by a mixture of animals nowadays extinct or living in either steppe or tundra.