The Upper Pleistocene deposits at Cassington, near Oxford, England

JOURNAL OF QUATERNARY SCIENCE (1998) 13 (3) 205–231 CCC 0267-8179/98/030205–27$17.50 1998 John Wiley & Sons, Ltd.

The Upper Pleistocene deposits at Cassington,near Oxford, EnglandD. MADDY1*, S. G. LEWIS1, R. G. SCAIFE1, D. Q. BOWEN2, G. R. COOPE3, C. P. GREEN3, T. HARDAKER4,D. H. KEEN5, J. REES-JONES3, S. PARFITT6 and K. SCOTT4

1Centre for Environmental Change and Quaternary Research, Department of Geography and Geology, C&GCHE, FrancisClose Hall, Cheltenham GL50 4AZ, England2Earth Sciences Department UCW Cardiff, PO Box 914, Cardiff CF1 3NE, Wales3Centre for Quaternary Research, Department of Geography, Royal Holloway University of London, Egham Hill, Egham,Surrey TW20 0EX, England4Baden Powell Quaternary Research Centre, University of Oxford, 60 Banbury Road, Oxford OX2 6PN, England5Centre for Quaternary Research, Geography Department, Coventry University, Priory Street, Coventry CV1 5FB, England6Department of Palaeontology, Natural History Museum, Cromwell Road, London SW7 5BD, England

Maddy, D., Lewis, S. G., Scaife, R. G., Bowen, D. Q., Coope, G. R., Green, C. P., Hardaker, T., Keen, D. H., Rees-Jones, J., Parfitt, S. and Scott, K. 1998.The Upper Pleistocene deposits at Cassington, near Oxford, England. J. Quaternary Sci., Vol. 13, pp. 205–231. ISSN 0267-8179

Received 22 May 1997 Revised 30 September 1997 Accepted 17 October 1997

ABSTRACT: For much of the Middle and all of the Upper Pleistocene the Upper Thames valleyhas remained outside the limit of ice advance. The main agents of landform evolution havebeen the River Thames and its tributaries, which have cut down episodically and in so doinghave abandoned a series of river terraces. This study reports the findings of an investigationinto exposures in the deposits underlying the Floodplain Terrace at Cassington, near Oxford,England. The sequence exposed reveals a stratigraphy of basal, predominantly fine-grained,lithofacies overlain by coarser gravel lithofacies. The fluvial architecture of these depositsindicates a major change in fluvial style from a low-energy (meandering) to a high energy(braided) channel system. The flora and fauna from the lower fine-grained lithofacies display amarked change from temperate at the base, to colder conditions towards the top, indicating aclose association between deteriorating climate and changing fluvial depositional style. Aminoacid and luminescence geochronology from the basal fine-grained lithofacies suggest correlationwith Oxygen Isotope Stage 5 and hence it is argued that the major environmental changerecorded at the site relates to the Oxygen Isotope Stage 5–4 transition. Deposition of much ofthe overlying gravel sequence probably occurred during Oxygen Isotope Stage 4, suggestingthat the latter half of the Devensian may be less significant, in terms of fluvial landscapeevolution in the Upper Thames valley, than was believed previously. 1998 John Wiley &Sons, Ltd.

KEYWORDS: Upper Pleistocene; River Thames; Oxfordshire; lithostratigraphy, geochronology; fluvialresponse.

Introduction

Recent advances in the understanding of climatic eventsduring the Upper Pleistocene, unravelled from ice-core andoceanic sedimentary records (Bond et al., 1993; Dansgaardet al., 1993), suggest the need for an urgent re-evaluationof terrestrial sequences that span this period (Boulton, 1993;Larsen et al., 1995). The environmental record of the south-ern and central English rivers has long been known tobe an invaluable resource for studying the British Upper

* Correspondence to: D. H. Keen, Centre for Quarternary Research, Geogra-phy Department, Coventry University, Priory Street, Coventry CV1 5FB,England.

Pleistocene. One such archive is that of the Upper Thamesvalley west of Oxford (Fig. 1).

For much of the Middle and all of the Upper Pleistocene,the Upper Thames valley has remained outside the limits ofice advance. The main agents of landscape evolution havebeen the action of the River Thames and its tributaries. Theriver has successively incised into the landscape abandoninga series of terraces underlain by fluviatile sediments at vary-ing altitudes above the present river. This sequence of riverterraces was examined and each terrace named by Sandford(1924). Later work by Arkell (1947), Briggs and Gilbertson(1973), Goudie (1976) and Briggs et al. (1985) has tendedto confirm this sequence and enhanced its interpretationby distinguishing lithostratigraphical and biostratigraphicalevidence for the further internal subdivision of units intocold and warm climate facies. Formal lithostratigraphical

206 JOURNAL OF QUATERNARY SCIENCE

Figure 1 Cassington Pit, Oxfordshire; plan of gravel extraction areas and location of Faces A–C and E.

nomenclature has been applied to this sequence by Bridg-land (1994), however, the terminology used here (Table 1)is that of Bowen et al. (in press).

This paper reports the findings of an investigation intoexposures in the Floodplain Terrace (Northmoor member ofthe Upper Thames Formation) at Cassington (SP4810, Fig.1) near Oxford and forms part of a larger investigation ofthe Upper Thames Valley.

Lithostratigraphy and sedimentology(D. Maddy, S. G. Lewis and C. P. Green)

The sedimentary sequence at Cassington was examined ona number of laterally extensive sections along working faces.The details of the sequence were recorded using verticalsedimentary profiles and major sedimentological features

Table 1 Upper Thames terraces and formal lithostratigraphy (afterSandford, 1924; Bowen et al., in press)

Terrace Stratigraphy Lithostratigraphy

Floodplain Terrace Northmoor MemberSummertown–Radley Summertown–Radley MemberTerrace Wolvercote Channel MemberWolvercote Terrace Wolvercote MemberHanborough Terrace Hanborough Member

1998 John Wiley & Sons, Ltd. J. Quaternary Sci., Vol. 13(3) 205–231 (1998)

were identified using detailed field diagrams supplementedby photomosaics (e.g. Figs 2 and 3).

The land surface at this locality is at 59 m OD and issome 1 m above the present river. The deposits are up to4 m in thickness and sedimentary structures are generallywell-preserved. The top ca 1 m comprises modern alluviumand in all the sections examined had been removed by theextraction company. The upper levels of the sequenceexposed shows evidence of disturbance, due most probablyto the formation of involutions.

The most extensive exposures were created during Phase2 of the extraction, between 1990 and 1992 (Fig. 1). At thistime two major faces were examined, and are labelled FaceA (Figs 1, 4 and 5) and Face B (Figs 1, 2 and 3) respectively.Further faces (C, D and E) were examined and recorded butonly brief reference is made here to Faces C and E (Figs 1and 5). Additional exposures created during Phase 4 (Fig.6) of the extraction (1993–1994) revealed further importantinformation, but at the time of examination were of poorerquality than those investigated during Phase 2. The majorityof the following description refers therefore to the Phase 2exposures, with reference to phase 4 exposures only whereimportant additional information was available.

Description of sedimentology

The recognition of erosional bounding surfaces within abody of sediment is of fundamental importance in theinterpretation of fluvial sedimentary sequences (Miall, 1996).A hierarchy of bounding surfaces ranging from 0 to 8 was

207UPPER PLEISTOCENE DEPOSITS AT CASSINGTON, UK

Figure 2 Face B; generalised sedimentology showing location of pollen profiles (P3 and 4), Mollusca (M6–11), Coleoptera (B2–4), smallvertebrate (V1–3) and OSL samples (865a–c).

Figure 4 Face A schematic diagram; showing location of pollen profile (P1), Mollusca (M1–5) and Coleoptera samples (B1).

defined by Miall (1996, p.82), each bounding bodies ofsediment resulting from processes acting over increasingspatial and temporal scales. For example, a bounding surfacemay delimit either individual facies (facies codes followMiall, 1996), defined by a second-order lower boundingsurface, or a facies association (a group of genetically linkedfacies, Reading (1986)), defined by a third-order lowerbounding surface.


This classification scheme can be applied to the successionat Cassington (Table 2). Five facies associations defined bythird or higher order bounding surfaces are recognised inthe succession (A–E; Table 2) and these form the basis of thesedimentological description below. A sixth-order boundingsurface (the basal erosional unconformity on the OxfordClay bedrock) delimits the entire succession at Cassington.Such an approach not only facilitates process-based interpret-


Figure 5 (a) Location of HA and HB; (b) section through lower part of the sequence through HB showing position of small vertebratesamples (V4–5); (c) plan of controlled excavation of hollow HB showing distribution of large mammal bones (excavated and recorded by T.Hardaker).

ation on a variety of temporal scales, but could readily beadapted to permit the future application of the principles ofsequence stratigraphy (Vail et al., 1977; Quirk, 1996) and/orallostratigraphy (North American Commission on Strati-graphic Nomenclature, 1983).

Association A

This comprises massive to crudely stratified, predominantlywell-sorted, limestone-dominated gravels, up to 1 m in thick-ness. This association forms a near-continuous basal depositat the eastern end of the pit (Fig. 1), however it has not, to


date, been recognised elsewhere in the exposures, suggestingthat sedimentation of this association is restricted to a rela-tively narrow zone, compared with the overlying coarsegravel deposits (association D). The base of the sequencelies on an eroded, planar bedrock surface.

Association B

Deposits of association B have been identified in a numberof contexts; as isolated scour hollows (Figs 4 and 5) and aschannel fills (Phase 4, Fig. 6) resting directly on the OxfordClay, and as laterally persistent units of laminated sands and


Figure 6 Location of sampling sites within phase 4 and position of Face E showing location of ice wedge cast shown in Fig. 7.

silts within the lower ca. 1 m of the succession (Figs 2 and3). This association is characterised by generally fine-grained,organic sediments. At the base of the succession a series ofellipsoidal scour hollows, formed in the lee of large (ca. 1 mdiameter) septarian nodules, are infilled with fine-grainedsediments above a thin lag-gravel. The deposits lining thesescours display bedding that is generally conformable withthe scour forms and in places contain clasts of the underlyingOxford Clay bedrock.

Higher in the succession, separated from these scour hol-lows by up to 1 m of gravels (association A), are laterallypersistent organic, laminated and ripple bedded sands, siltsand clays, up to ca. 1 m in thickness. These sedimentsoverlie a subhorizontal lower bounding surface and are over30 m in lateral extent in Face B (Fig. 2). A thin (10–20 cmgravel layer) occurs within this fine-grained sequence (Fig. 2).

Association C

This comprises sand facies and is laterally discontinuous,but where present it is up to 1 m in thickness (Fig. 2). Thebase of the unit is erosional and in most cases is channelled(lies on a concave-up bounding surface) into the underlyingsediments. The sands range from medium to fine. Multipleshallow channel fills are evident (Figs 2 and 3), with chan-nels often showing high width–depth ratios.

Association D

This association comprises a predominantly coarse gravel,which can be traced throughout the whole worked area and


is the main constituent of this sedimentary sequence, beingup to 2 m in thickness. The predominant facies is laterallycontinuous subhorizontal gravel sheets (10–15 cm inthickness), which display fining upwards cycles. The base iserosional and in many places is channelled (lies on a con-cave-up bounding suface) both into the underlying sedimentsand through them to rest directly on the Oxford Clay (Fig.2). The gravel clasts range up to 15 cm long axis and fineupwards. Multiple shallow channel fills are evident, withchannels often showing high width–depth ratios.

Association E

Overlying association D is a medium to fine gravel, 1.5 min thickness (Fig. 2). This association is distinct in theexposures in phase 2 of the extraction, but becomes lesseasily distinguishable from association D over the remainderof the worked area. This association lies on a planar lowerbounding surface, which due to the subhorizontal beddingof the upper parts of association D may appear in placesconformable with it. However, the gravels are finer thanthose of association D. In Face E (Phase 4, Figs 1 and 6)the two associations (D and E) are clearly divisible by thepresence of a distinct bounding surface, which is punctuatedby an ice-wedge cast (Fig. 7) and by the occurrence of asmall channel infilled with detrital plant debris and otherorganic material. The uppermost sections of this associationoften display disturbance, with loading structures evident.


Table 2 Lithofacies associations identified at Cassington

LowerFacies bounding Probableassociations Facies surface (order) Geometry Interpretation Element planform

E Gm, Sm, (4) Planar and Tabular, laterally extensive Bar core CH, GB, BraidedSs erosional planar bedded gravels up to (longitudinal) and SB

1.5 m in total thickness. Beds bar top10–15 cm. Isolated sets of sedimentation.planar cross-bedded sands Slough channel fills

D Gm, Gp, (5) Planar and Laterally persistent planar Vertical bar platform CH, GB, BraidedSp erosional. bedded coarse gravel in excess aggradation. SB

Locally of 20 m in length. Wedge Laterally down-filledconcave up units of tabular cross-bedded channels.

gravel orientated normal to Agglomerated unitschannel axis and extending of in-channel barfrom channel sides. Tabular, (longitudinal)laterally extensive units of deposition. Bar topmassive to planar bedded and bar tailgravel up to 1.5 m in sedimentationthickness. Tabular cross-bedded gravel units orientatedparallel to transport direction(down-valley), interbeddedwith units of massive gravel.Lenticular beds of planarbedded sands up to 50 cmthick. Isolated sets of planarcross-bedded sand

C St, Sm (5) Concave-up Trough cross-bedded and Channel-fill CH ?Transitionalmassive sands. ?Some low- sequenceangle lateral accretion units

B Sm, Sl, (3) Planar and Laminated and ripple bedded Bar top (suprabar SB, OFSr Fl, conformable sands, silts and clays. Thin platform)Fm, Fcf, pebble beds. Some low-angle sedimentation,

lateral accretion units overbank fines

A Gm (6) Planar and Laterally persistent planar Agglomerated GB Meanderingerosional bedded gravels in excess of sequence of in-

20 m in length and up to 1 m channel, barin thickness deposition (bar

platform). Lagdeposits also presentlocally

Interpretation

Association A represents superimposed channel-fillsequences, where low-angle beds may represent lateralaccretion surfaces, although no epsilon cross-beds (Allen,1963) were observed. Observations on other faces confirmthe presence of asymmetrical channel fills, with evidence ofundercut bank collapse, within this unit. These channelsoften display low width–depth ratios. Such geometry is con-sistent with formation in a sinuous channel. The widespreadbasal gravel facies (Gm, Gh) probably represents bar coresediment (bar platform; Bluck, 1971).

The scoured lower bounding surface is clearly associatedwith flow separation around the septarian nodules. Flowaround these obstructions leads to flow convergence in thelee, resulting in scour of the underlying Oxford Clay surface.The concordant fill suggests that the planation and scour of


the bedrock was contemporaneous with the deposition ofthe overlying sediment.

Association B suggests accumulation as a result of verticalaccretion, most probably as overbank flood deposits and asfine-grained infills of floodplain pools. The relationshipbetween associations A and B is complex. Association Boccurs at the base of the succession and underlies assoc-iation A, where it occurs in the scour hollows. Deposits ofAssociation B also occur in Face B (Fig. 2), with gravels ofassociation A both above and beneath them. This suggeststhat deposition of these two sets of facies is closely relatedand the succession varies both vertically and laterally.

The sequence represented by associations A and B is verysimilar to recent (Holocene) valley fills. The succession isconsistent with deposition in a meandering gravel bed river(Bluck, 1971). The widespread preservation of low-energyfacies (association B) would tend to support this interpret-


Figure 7 Photograph of intraformational ice wedge cast foundwithin gravels of association D overlain by association E.

ation and the complexity of the succession may reflectrepeated migration of the channel across this area of thefloodplain. Frequent overbank flooding is consistent with adischarge regime similar to that of the present day RiverThames.

Association C represents a change in fluvial style andhigher stream power. The channels have relatively highwidth–depth ratios, but bank collapse structures indicatesome bank cohesion, where the river has undercut banksformed in the underlying sediment. This cohesion couldresult from the relatively high proportion of fine-grainedsediment in the materials forming the banks, or alternativelycould indicate frozen bank material. It is likely that theplanform is transitional between the sinuous planform of theunderlying sediments and the multichannel planform of theoverlying sediments.

The coarseness of the gravel of association D suggest highstream power. The extensive nature of these facies indicatesthat deposition took place over a wider floodplain areathan is indicated for the underlying sediments, and suggestsconsiderably higher sediment supply. Major channels areinfilled by coarse gravel facies, often on progradationalbedforms. The preservation and formation of relatively deepchannel fills may be due to the channel bank stabilityafforded by the fine-grained sediments into which the chan-nels are eroded. Later sedimentation would have beenrestricted to channels cut into coarse sediments, which lackcohesion and hence form unstable banks. The superimposedgravel sheets most likely represent bar-core sediments, andtheir lateral persistence together with the low-amplitudeplanar foresets (observed in Face A normal to Face B


described above) suggests formation on large low-amplitudebedforms, most probably longitudinal bars. Minor channelshave high width–depth ratios and display simple fills oftenof coarse sand. This filling of slough channels has beenassociated with rapid fill during a single run-off event(Bryant, 1983) and probably represents a spring freshet of anival type discharge regime.

Large gravel bars, punctuated by numerous major channelsand smaller slough channels strongly suggests deposition ina multiple channel (braided) system. This is also supportedby the lack of preservation of fine-grained facies and theabsence of lateral accretion surfaces associated with moresinuous planforms.

Although similar structures are recorded in association E,the gravels are distinctly finer (fine–medium). The planarlower bounding surface suggests an erosional contact andindicates a reactivation of sediment movement. The struc-tures suggest deposition in a multichannel system. Obser-vations on Face E (Fig. 7) indicate the formation of intraform-ational ice wedges. This confirms deposition under coldclimate conditions. Movement of the channel zone is indi-cated by the polymorphic nature of ice-wedge formation,demonstrating that sedimentation on this part of the flood-plain had become episodic.

The change from association D to E could simply reflecta shift in the sedimentation zone or alternatively it maysignify changing discharge and/or sediment supply conditionsresulting from changing climatic conditions.

Pollen (R. Scaife)

The exposures were sampled for a variety of biostratigraph-ical investigations. A summary showing the stratigraphicalpositions of samples taken is shown in Fig. 8.

A total of seven localities (P1–7) were sampled for pollen,four during 1991 (P1–4) and a further three during 1994(P5–7). Three pollen profiles from Cassington are reportedhere (Fig. 9). Sections P1 (adjacent to Face A, Figs 4 and9a) and P4 (Face B, Figs 2 and 9b) are from association Band were sampled during 1991. A further sequence P5 (Fig.9c) was taken from the 1994 exposures at location 4A (Fig.6). Single spot pollen counts are also reported, sample P2from a macrofossil bed located between associations D andE (Face A, Fig. 4) and Sample P6 from location 4B (Fig. 6).

Sampling for pollen analysis was undertaken from theopen pit faces. Pollen extraction was undertaken using nor-mal techniques (Moore et al., 1991) but with micromeshsieving at 10 mm and decanting of coarse material to assistwith removal of fine debris and coarser sand. Samples ofca. 10 ml were used. Quaternary pollen and spores, althoughpresent in low absolute frequencies, were generally wellpreserved. The low absolute pollen frequency values areattributed to the taphonomy of pollen in these coarse flu-vial sediments.

Derived Jurassic palynomorphs were extremely abundantand counts were not made because percentages would havebeen meaningless. Because of the abundance of these palyn-omorphs, identification and counting of saccate grains wasmade with caution. Although this is not a problem withPinus, because Pinus pollenites is a rare taxon in the Jurassic,grains of Picea and Abies might have posed a problem.However, the derived palynomorphs were readily identifi-able, being more degraded, displaying much darkercolour/stain and exhibiting morphological differences,


especially the reticulation of the saccae. It is thought thatthe grains of Picea and Abies are contemporaneous with thesediments (because of the preservation), however, derivationfrom earlier Pleistocene terrace deposits should not be pre-cluded. Crabtree and Hunt (in Briggs et al., 1985) bothidentify similar pollen assemblages from comparablesequences in the Upper Thames valley.

Pollen sums are less than standard, with counts on averageof 100–150 grains per level for P1 and P4 and 200–250 forP5. Data are calculated as a percentage of total dry landpollen (t.d.l.p.). Marsh types and spores are calculated as apercentage of t.d.l.p. plus marsh types and spores respect-ively. Taxonomy follows that of Stace (1991) and the modi-fied pollen taxonomy of Moore et al. (1991) by Bennett etal. (1994). The data from each of the sections examined aredescribed below.

Section P1 (Fig. 9a)

Seven contiguous samples were taken from a thin (14 cm)sequence of laminated organic sands–silts resting on bedrock(Fig. 4). There are few evident changes in the pollen spectraand no zonation has been attempted (Fig. 9a). The pollenprofile is characterised by dominant Pinus with Poaceae,Cyperaceae, Lactucae and Plantago sp. Arboreal pollen, asnoted, is dominated by Pinus, with declining percentagesfrom 40% at the base to 20% at the top. Low but consistentvalues of Picea are noted (5% maximum). Deciduous treesare present throughout, with Betula and traces of Carpinus,Fraxinus and Alnus, which with the exception of Carpinusare more abundant in the lower part of the profile. Shrubsare few, with traces of cf. Juniperus and Corylus, and dwarfshrubs Erica and Calluna. Halophytic elements are presentwith Armeria ‘A’ and ‘B’ line, Plantago cf. maritima andpossibly large Poaceae (. 50 mm). Wetland elements aredominated by Cyperaceae, with marginal Alisma type (A.plantago-aquatica?), and Typha angustifolia/Sparganium typeand Sphagnum. Freshwater Pediastrum is present.

No true aquatic plant types other than small numbers ofalgal Pediastrum are present. Cyperaceae and associatedmarginal aquatic plants suggest local sedge/reed swamp inshallow standing/slow-flowing water. A substantial peak of

Figure 8 Schematic lithostratigraphy and stratigraphical position of biostratigraphical and geochronological sampling.


Equisetum spores may represent final silting and colonisationof the basin/depression.

Pinus is dominant throughout, with all other arboreal taxapresent in small numbers. Declining Pinus through the profilemay be a statistical function of increasing percentages ofherb taxa (largely Poaceae). Values of Pinus suggest thatlocal/regional pine woodland was important. This is inter-preted as open coniferous woodland with herbaceous under-storey communities. For open steppe/tundra vegetation,greater herb diversity and typical taxa (e.g. Artemisia, Cheno-podiaceae and higher percentages of Poaceae) might beexpected. The presence of halophytic elements (pollen ofArmeria ‘A’ and ‘B’ line, Plantago cf. maritima and possiblysome large Poaceae) is, however, typical of floral assem-blages associated with cooler conditions (Bell, 1969, 1970).

Section P4 (Fig. 9b)

This pollen sequence of 70 cm spans organic fills of lowerand upper channels, a coarse gravel unit and overlyinglaminated sands (Fig. 2). Overall, the pollen is dominatedby Pinus, Picea, Lactucae indet. and Poaceae. Two pollenzones are recognised and characterised as follows.

CASP4:1 (73 cm–45 cm)

Stratigraphically this lower zone spans two channel fills(junction at 56 cm) and is delimited by greater numbers ofPinus (up to 65%) and Picea (up to 20%). Abies (3%) ispresent in this and overlying CASP4:2. Small numbers ofthermophiles are present, including Betula, particularly inthe lowest levels, Quercus, Tilia and Alnus. Herbaceousdiversity is also greater than in the above zone CASP4:2.Ranunculaceae, Dianthus type, Chenopodiaceae and Plan-tago media/major type are of note. Spores of Dryopteris type(monolete) and Polypodium have higher percentage valuesin the lower part of this zone.

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Figure 9 (a) Pollen profile P1 (Face A); (b) pollen profile P4 (Face B); (c) pollen profile P5 (Phase 4). For key to lithological column see Fig. 2. Pollen percentages less than 1% are shown as a cross. Notealso the variable axis percentage scales.

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Figure 9 (a) Pollen profile P1 (Face A); (b) pollen profile P4 (Face B); (c) pollen profile P5 (Phase 4). For key to lithological column see Fig. 2. Pollen percentages less than 1% are shown as a cross. Notealso the variable axis percentage scales.

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CASP4:2 (45 cm–3 cm)

This upper zone, including a possible subzone (15 cm–8 cm)is stratigraphically complex, with organic silts and sands,laminated white sands and a coarse unit not containingpollen (20–30 cm). Pollen assemblages are characterisedthroughout by Pinus, Lactucae indet. and Poaceae. Piceavalues are consistent but lower than in CASP4:1. Betulavalues increase upwards. Juniperus, Corylus avellana typeand Alnus show a small but consistent presence. Quercusand Tilia are absent. Herbs are dominated by Lactucae andPoaceae, but with Dianthus type and Plantago media/majortype. Armeria ‘A’ line in the upper levels is of note. Amaximum of Poaceae (8–15 cm) might be a pollen assem-blage subzone but is possibly a taphonomic phenomenon.Spores of Botrychium lunaria are more abundant.

Aquatic and wetland taxa are present in only small numbers.Cyperaceae are most important and with other taxa, haveslightly higher values in CASP4:1. Taxa include Caltha type,Alisma type, Typha angustifolia type and Sphagnum. Fresh-water algal cysts of Pediastrum are present throughout theprofile. Aquatic taxa are frequently under-represented inpollen spectra and given the preservational environment andsmall pollen sum at this site, it is not surprising that thereare few true aquatic taxa present.

In the terrestrial communities there is a clear dominanceof Pinus throughout this profile. Values are considered toohigh to be accounted for by long-distance dispersal factors,even in a completely open arctic environment. The presenceof Picea, especially in pollen assemblage zone CASP4:1, issimilarly of importance and it is concluded that the environ-ment was one of open, mixed pine and spruce woodland.This is in accord with the relatively small herbaceous diver-sity here when compared with pollen spectra from sites withtypical Arctic/Alpine plant assemblages. A conifer forest ofopen aspect similar to the boreal/Fennoscandian forests ofcentral/southern Sweden and Finland is envisaged. To whatextent the herb component recorded derives from floodplainhabitats or woodland floor is unclear. Although this basicconiferous environment is indicated throughout the pollensequence, there is a clear change between zone CASP4:1and CASP4:2. The lower (CASP4:1) appears to have greaterrepresentation of thermophiles. There is, however, no appar-ent change across the stratigraphical boundary between thelower and upper channel fills, suggesting only a minortemporal hiatus at this horizon. The change from CASP4:1to CASP4:2 is not, however, accompanied by any markedstratigraphical change that might imply changes in taphon-omy or environment during a hiatus of sedimentation orerosive phase. The sequence P1 may correlate with the basalzone CASP4:1.

Section P5 (Fig. 9c)

Section P5 comprises organic sands and silts that infill asmall channel cut into the underlying Oxford Clay. Nopollen assemblage zonation was carried out on this 70 cmsequence because of the homogeneity of the pollen spectra.The profile as a whole is characterised as follows. Herbpollen is dominant (to 80% t.d.l.p.) with Poaceae (average45%), Ranunculus type, Plantago major type, Plantago sp.and Asteraceae types (Lactucae to 5%). Although the spectraare not very diverse, attention is drawn to Linum biennetype and Linnaea borealis at the top of the profile. Wetland


taxa comprise Cyperaceae (up to 20%) and sporadic occur-rences of Myriophyllum alterniflorum, Sagittaria and Typhaangustifolia type. Of the tree pollen (25% t.d.l.p., except at50 cm with 36% t.d.l.p.) Pinus is most important (average20% t.d.l.p.), with consistent but small values of Betula andPicea present (,5% t.d.l.p.). A single grain of Carpinusoccurs at 40 cm. Shrubs comprise sporadic Juniperus, Cal-luna and Empetrum.

The pollen evidence from P5 suggests open herbaceouscommunities. These may have been grassland dominatedwith tall herb types and dry grassland communities. Plantagomedia/major type is evident in all Cassington profiles, andalthough possibly representing disturbed ground (P. major),it also may be a constituent of the grassland (P. media). Aswith the other profiles, halophytic elements are present, andhere represented by Plantago maritima. Marsh and aquaticcommunities are attested by Cyperaceae, Sphagnum andmarginal/aquatic Typha/Sparganium and Sagittaria, withaquatic Callitriche, Myrophyllum alterniflorum and algalPediastrum. If there was local tree growth (Pinus and Picea)it is suggested that these were only sporadic in an otherwiseopen herbaceous landscape. Linnaea borealis is, however,or particular note in this pollen profile (0–1 cm), today beinga rare herb of shade under rocks as ground flora, especiallyunder coniferous woodland (Stace, 1991).

When P5 is compared with pollen sequences P1 and P4(Fig. 9a and b) it is clear that greater similarity exists withthe former, with tree pollen values of ca. 20% and herbs at80% compared with P4 (local pollen assemblage zoneCASP4:1), where Pinus has fluctuating values of 40–65%.Furthermore, there are fewer deciduous thermophiles.

Sample P2

A single pollen sample has been examined from a smallchannel fill containing abundant plant macrofossils at thislocation (Fig. 4). Betula is dominant (37% total pollen),with Poaceae (31%). Additional tree taxa recorded incudesporadic occurrences of Quercus, Alnus and Corylus avel-lana type. A small number (2) of Erica sp. is recorded. Thereare few herbs but Dianthus type and Artemisia are of note.

From the abundant small ‘twigs’ of cf. Betula in thechannel, the dominance of birch pollen is not surprising.This small macrofilled channel possibly represents trappedflood debris, but is still likely to represent local growth. Thepollen appears to be of tree birch type (as opposed toBetula nana). Identification of the numerous twigs has provendifficult but they appear to be tree Betula sp., thus indicatingbirch woodland/scrub in an otherwise open-steppe land-scape.

Sample P6

Well preserved pollen was obtained from a thin peat/organiclayer resting directly on the Oxford Clay at location 4B (Fig.6). A single pollen spectrum from section P6 differs markedlywith sections P1 and P4 described above. Poaceae aredominant, with Plantago media/major type and a moderatelydiverse assemblage of other herb types. In contrast there isrelatively little tree pollen with only small numbers of Pinus,Picea, cf. Abies and Betula.

The pollen spectrum from this section differs substantiallyfrom the data discussed for other parts of the pit. Here,


Table 3 Cassington Coleoptera

B5 B3 B1 B6

CarabidaeCarabus problematicus Hbst. 1 1Carabus granulatus L. 1Carabus sp. 1Notiophilus palustris Duft. 3Notiophilus aquaticus (L.) 4 3 4Pelophila borealis (Payk.) 1Elaphrus cupreus Duft. 1 1Loricera pilicornis (F.) 2 1Clivina fossor (L.) 4 1Dyschirius globosus (Hbst.) 1 2 1Dyschirius sp 1Trechus rivularis (Gyll.) 3Trechus obtusus Er. 2Bembidion properans (Steph.) 4Bembidion bipunctatum (L.) 4 2 1Bembidion dentellum (Thunb.) 1*Bembidion fellmanni Mannh. 1Bembidion gilvipes Sturm. 24Bembidion doris (Panz.) 1Bembidion octomaculatum 1(Goeze,)Bembidion obtusum Serv. 1*Bembidion dauricum (Mtsch.) 2Bembidion biguttatum (F.) 6Bembidion guttula (F.) 3Bembidion spp. 5Patrobus septentrionis Dej. 2 1Patrobus assimilis Chaud. 1Poecilus sp. 1Pterostichus strenuus (Panz.) 1Pterostichus nigrita (Payk.) 1 1Pterostichus anthracinus (III.) 2Pterostichus vernalis (Panz.) 1Pterostichus melanarius (III.) 3*Pterostichus middendorffi (Sahlb.) 1Calathus melanocephalus (L.) 8 1Agonum moestum (Duft.) or 2viduum (Duft.)Agonum fuliginosum (Panz.) 1Amara ovata (F.) 2Amara familiaris (Duft.) 2Amara tibialis Payk.) 1Amara quenseli (Schonh.) 4Amara bifrons (Gyll.) 3Amara alpina (F.) 2Amara sp. 1Chlaenius nigricornis (F.) 1 2Badister bipustulatus (F.) 2Cymindis vaporariorum (L.) 1Syntomus truncatellus (L.) 2

DytiscidaeHydroporus sp. 1Potamonectes depressus elegans 2 1(Panz.)Agabus congener (Thunb.) type 1Ilybius sp. 1*Colymbetes dolabratus (Payk.) 1Colymbetes sp. 1


Table 3 Continued

B5 B3 B1 B6

GyrinidaeGyrinus minutus F. 1Gyrinus sp. 2 1Orectochilus villosus (mull.) 2

HydraenidaeHydraena sp. 2 3Ochthebius cf bicolon Germ 3Ochthebius cf minimus (F.) 1Ochthebius lenensis Popp. 2*Helophorus obscurellus Popp. 18Helophorus nubilus F. 2 1 1*Helophorus sibiricus Mtsch. 11Helophorus grandis III. 3 7 4Helophorus “aquaticus” (L.) 1 5*Helophorus splendidus Sahib. 193Helophorus spp. 12 16

HydrophilidaeCoelostoma orbiculare (F.) 1Sphaeridium sp. 3Cercyon melanocephalus (L.) 1 1Cercyon marinus Thoms. 1Cercyon pygmaeus (III.) 5 1Cercyon convexiusculus Steph. 1Cercyon tristis (III.) 3 1Cryptopleurum minutum (F.) 2Hydrobius fuscipes (L.) 1 2 1Laccobius spp. 2

HisteridaeHister (sensu lato) spp. 3

SilphidaeThanatophilus dispar (hbst.) 1Silpha tristis III. 3Phosphuga atrata (L.) 1

OrthoperidaeOrthoperus brunnipes (Gyll.) 5

PtiliidaeAcrotrichis sp. 2

Staphylinidae*Pycnoglypta lurida (Gyll.) 1Olophrum fuscum (Grav.) 8 14*Olophfrum boreale (Payk.) 3*Acidota quadrata (Zett.) 3Acidota crenata (F.) 1Lesteva longelytrata (Goeze,) 4Geodromicus nigrita (Mull.) 2 2*Boreaphilus henningianus Sahlb. 1 6*Holoboreaphilus nordenskioldi 4(Makil.)*Aploderus caesus (Er.) 3Anotylus rugosus (F.) 11 1 1*Anotylus gibbulus Epp. 1Platystethus arenarius (Fourcr.) 11

Platystethus cornutus (Grav.) 3 2Platystethus nodifrons Mannh. 4 1 1Platystethus nitens (Sahib.) 4 1Bledius sp. 1Stenus spp. 4 18 11Euaesthetus laeviusculus Mannh. 1


Table 3 Continued

B5 B3 B1 B6

Lathrobium sp. 4Xantholinus spp. 8Philonthus sp. 5Trichoderma pubescens (Geer,) 1Ocypus cupreus (Rossi.) or 1aeneocephalus (Geer,)Quedius sp. 3Tachyporus chrysomelinus (L.) 3 2Tachyporus sp. 2*Tachinus caelatus Ullrich, 2Tachinus spp. 2Aleocharinae gen. et sp. indet 13 2 5 69

ElateridaeAgriotes sp. 3Hypnoidus riparius (F.) 1*Hypnoidus rivularis (Gyll.) 3Oedosthetus quadripustulatus (F.) 2

DryopidaeElmis aenea (Mull.) 1Esolus sp. 3Oulimnius tuberculatus (Mull.) 1Oulimnius troglodytes (Gyll.) 1Limnius volckmari (Panz.) 1Riolus sp. 3

GeoryssidaeGeorissus crenulatus (Rossi,) 1 1

HeteroceridaeHeterocerus sp. 1

ByrrhidaeSimplocaria semistriata (F.) 1 3*Simplocaria metallica (Sturm,) or * 2 3 4elongata (Popp.)Cytilus sericeus (Forst.) 1 1Byrrhus fasciatus (Forst.) 1Byrrhus sp. 1 1*Curimopsis cyclolepidia (Munst.) 1

CryptophagidaeAtomaria mesomelaena (Hbst.) 8Atomaria sp. 4 1

PhalacridaeStilbus oblongus (Er.) 1

Lathridiidaecf Corticaria spp 9 2

CoccinellidaeScymnus (sensu lato) sp. 3*Hippodamia arctica Sch. 6Coccinella sp. 1 1

TenebrionidaeCrypticus quisquilius (L.) 2

ScarabaeidaeTrox sabulosus (L.) 1Geotrupes sp. 1 1Onthophagus vacca (L.) 1Aegialia sabuleti (Panz.) 0 1Aphodius fossor (L.) 1Aphodius rufipes (L.) 1 1


Table 3 Continued

B5 B3 B1 B6

Aphodius spp. 39 4 13 26Heptaulacus villosus (Gyll.) 1ChrysomelidaeMacroplea appendiculata (Panz.) 1Donacia clavipes F. 3Donacia crassipes F. 3Donacia dentata Hoppe, 1Donacia semicuprea Panz. 1Donacia thalassina Germ. 2Plateumaris sericea (L.) 2Chrysomela staphylea L. 1Chrysomela marginata L. 2 1Gastroidea viridula (Geer,) 1 1Phaedon cochleareae (F.) 2Hydrothassa glabra (Hbst) 3Melasoma collaris (L.) 1Phytodecta sp. 1Galeruca tanaceti (L.) 2Phyllotreta vittula (Redt.) 1Phyllotreta flexuosa (III.) 2Haltica sp. 1Crepidodera ferruginea (Scop.) 1Chaetocnema sp. 25Psylliodes sp. 2

CurculionidaeApion spp. 27 1 5Otiorhynchus ligustici (L.) 2Otiorhynchus clavipes (Bonsd.) 2 1groupOtiorhynchus arcticus (F.) 5Otiorhynchus raucus (F.) 3Otiorhynchus dubius (Strom,) 4Otiorhynchus ligneus (Ol.) 4 1Otiorhynchus rugifrons (Gyll.) 3Otiorhynchus ovatus (L.) 2Phyllobius sp 2Trachyphloeus sp. 4Strophosoma faber (Hbst.) 1 2Barynotus obscurus (F.) 4 1Sitona flavescens (Marsh.) 4Sitona spp. 56 4 1*Coniocleonus sp. 2Bagous sp. 1Tanysphurus lemnae (Payk.) 2Notaris bimaculatus (F.) 5 1 1 2Notaris acridulus (L.) 2 14Notaris aethiops (F.) 13 1Grypus equiseti (F.) 1 1Liparus coronatus (Goeze,) 1Alophus triguttatus (F.) 3 5Hypera nigrirostris (F.) 1Hypera sp. 1Limnobaris pilistriata (Steph.) 2

there is no indication of the presence of woodland or eventrees in the local environment. From the data it appears thatthis thin organic unit accumulated under open conditionsdominated by herb communities consisting of possibly dis-turbed ground (Plantago major type, Convolvulus), grasslandand tall herbs (Thalictrum, Centaurea sp.). Halophytes


include pollen of Chenopodiaceae and Armeria ‘A’ line.Seeds of the former are also present.

Summary

The pollen profiles P1 and P4 show a predominantly conifer-ous wooded environment. Profile P5 indicates more openherbaceous communities, with only sporadic tree growth.Samples P2 and P6 show an open environment without thedominant coniferous (pine with some spruce) woodland.

The predominantly herbaceous pollen assemblages andtheir floristic diversity is suggestive of a generally openlandscape such as might be expected in Arctic steppe/tundra.Pinus is the dominant tree pollen taxon and this immediatelyraises the question as to whether this is from pine forest butof long distance origin (Lichti-Federovich and Ritchie, 1968)or from a more open landscape with locally scattered pinein the near region. In profile P5 (Fig. 9c), where percentagesare in the order of 10–20% of total pollen, this questionremains problematic. However, profiles P1 (Fig. 9a) and P4(Fig. 9b) have in the order of 30–40% Pinus and many levelsof 60–80%, also associated with Picea. This assemblage issuggestive of areas of open aspect pine and spruce forestwith a herbaceous ground flora. Such an interpretation is inaccord with the other palaeoecological data suggesting anenvironment similar to southern Scandinavia today.

Coleoptera (G. R. Coope)

Six samples for coleopteran analysis (B1–6) were taken froma number of localities in both 1991 (Phase 2) and 1994(Phase 4). The insect remains were extracted by the standardtechnique described by Coope (1986). Only four of these(samples B1, B3, B5 and B6) yielded Coleoptera in sufficientnumbers and in adequate preservational state to permitdetailed environmental interpretations. The Coleoptera fromfour samples are listed in Table 3 in which the taxonomicorder and nomenclature follows that of Die Kafer Mitteleur-opas: Katalog (Lucht, 1987) as far as is possible, but thosespecies with a geographical range outside central Europehave been inserted in the most appropriate taxonomic pos-itions.

In Table 3, the four samples are arranged in stratigraphicalorder, the lowest being sample B5 which was sampled fromlocation 4A during 1994 (phase 4, Fig. 6). Samples B1 (FaceA, Fig. 4) and B3 (Face B, Fig. 2) are stratigraphicallyintermediate and have been arranged here on the groundsof faunal similarity. Sample B6 (location 4D, phase 4, Fig.6) is from the highest sampled stratigraphical level.

In Table 3 the numbers opposite each species name andunder each sample number indicate the minimum numbersof individuals present in the sample and are calculated onthe basis of the maximum numbers of any diagnostic skeletalelement of that species in the sample. Altogether 201 taxaof Coleoptera have been recognised, of which 154 can benamed to species or species group; 20 of these species areno longer living in the British Isles. They are indicated byp in Table 3.


Environmental implications of the Coleoptera

The specific composition of the coleopteran assemblages isdifferent in all four samples. The greatest contrast is betweenthe fauna from Sample B5 compared with that from SampleB6, and these will be considered separately. Samples B1and B3 are faunally somewhat intermediate in position, butare sufficiently similar to be considered together.

Sample B5

Aquatic environments indicated by the Coleoptera are oftwo main types. Running water is the habitat of Orectochilusvillosus, which hunts over the surface. Oulimnius tubercul-atus is a subaquatic beetle that lives among stones andmosses in rapidly moving water. Both these species are rarein this fauna. Beetles indicative of still-water habitats aresimilarly rare. Among the carnivorous water beetles, Hydrop-orus and Colymbetes are represented by single individuals.Species of Helophorus are mostly characteristic of shallowponds and Coelostoma orbiculare and Hydrobius fuscipesalso inhabit small pools choked with decomposing veg-etation. Some indication of the nature of this aquatic veg-etation is provided by the phytophagous Coleoptera. ThusTanysphyrus lemnae is a minute weevil that feeds on theduckweed Lemna. Donacia crassipes feeds on water liliesand the host for Donacia dentata is the arrowhead pondweed Sagittaria.

The existence of both running and standing water indi-cators in the same deposit is in no way incompatible. Thefossils have been brought together, either actively by flyingin or passively by being washed or blown in, so that thefossil assemblage represents the sweepings of the landscape,representative of many of the habitats in the surroundingneighbourhood. In any natural stream that has not beencanalised in the interests of flood control, there will benumerous riffles, pools, backwaters and abandonedmeanders providing the variety of aquatic habitats indicatedby the fossil assemblage.

Riparian environments adjacent to the water’s edge withvarying amounts of vegetation cover are indicated by avariety of Coleoptera. Silty banks free from vegetation are thehabitats of species of Bledius, which systematically burrow inthe damp sediment, turning it over to a depth of severalcentimetres, feeding on algae. Clivina fossor burrows indamp silty places, preferring open areas where the vegetationis patchy. Bembidion properans actively hunts on the surfaceof muddy silt banks near to the water, where they areexposed to the sunlight and where there is only sparsevegetation (Lindroth, 1992). Bembidion octomaculatum isoften associated with muddy soils beside very small puddlesthat tend to dry out in summer.

Marshy habitats with a rich vegetation of reedy plantsmust have been relatively common. Phytophagous speciesthat feed on this swamp vegetation include: Donacia clav-ipes, which feeds mainly on Phragmites communis; Donaciasemicuprea and Notaris acridulus, the host plant of which isthe sweet grass Glyceria; and the weevil Notaris bimaculatus,which feeds on a variety of aquatic grasses, including Gly-ceria. The phalacrid Stilbus oblongus is also a species ofswamps with reedy vegetation, such as Phragmites or Typha,where it lives among the plant detritus and is probably analgal feeder.

Other phytophagous species of wet habitats include: Chry-somela staphylea, which is rather polyphagous on her-baceous plants as an adult, but has larvae that are mono-


phagus on Plantago maritima; Gastroidea viridula, which isalmost entirely restricted to the larger species of Rumex andoccasionally Polygonum; Phaedon cochleariae, which feedson a variety of Cruciferae in damp places; and Hydrothassaglobra, which eats various species of Ranunculaceae. Theweevil Grypus equiseti attacks the roots and stem of speciesof Equisetum, especially E. fluviatile and E. arvensis.

Amongst the carnivorous and scavenging carabid beetles,the following species live near water in damp leaf litterwhere the vegetation is thick, providing shade and wherethe soil is humus rich, thus they are often found in wood-lands; Carabus granulatus, Notiophilus palustris, Trechusobtusus, Bembidion dentellum, B. gilvipes, B. biggutatum,B. guttula, Pterostichus strenuus, P. nigrita, P. anthracinus,P. vernalis, Agonum moestum/viduum and A. fuliginosum.Badister bipustulatus lives in swamps beside eutrophic pools.Many of the carnivorous staphylinid species, such as Ano-tylus rugosus, Platystethus nodifrons, P. nitens and Euaes-thetus laeviusculus, are also found in damp places amongstvegetable detritus. Helophorus nubilus lives in damp muddylocalities under vegetable detritus.

The habitat preferred by Chlaenius nigricornis has beendescribed by Lindroth (1992, p. 329) and may be summar-ised as loamy or loamy, sand banks, rich in vegetation, witha firm soil, beside stagnant or slowly, flowing bodies offresh, eutrophic water, where the vegetation usually consistsof the larger species of Carex but with bare patches inbetween, where the species prefers to stay hidden underpieces of debris washed ashore. This detail is given here asan illustration of the precise information that is available formany species and which can be used in palaeoenvironmen-tal interpretations.

Away from the marshy ground there is evidence thathabitats gradually became drier, with a well drained sandysubstrate and on which the vegetation was patchy with areasof bare soil between the plants. Such environments arerequired by the carabids Carabus problematicus, Amaraovata, Amara familiaris, Amara tibialis, Amara bifrons andSyntomus truncatellus. A number of these species are decid-edly heliophilous, that is they are active in bright sunlight.The tenebrionid, Crypticus quisquilius and the elaterid Oedo-stethus quadripustulatus are similarly restricted to sandy habi-tats, where they live under stones or plant detritus.

Many of the phytophagous Coleoptera are also xerophiles,that is they prefer dry habitats. These include: Chrysomelamarginata, which feeds on a variety of Asteraceae; Crepidod-era ferruginea, which frequently feeds on grasses;Otiorhynchus ligustici and Barynotus obscurus are both poly-phagous weevils, the larvae of which feed underground ongrass roots; Strophosoma faber lives in warm sandy placeson various species of Asteraceae, but its larvae also feed ongrass roots; the larvae of Heptaulacus villosus feed in thehumus-rich soil between the grass roots; the weevil Liparuscoronatus lives on the larger species of Apraceae, such asAnthriscus, Chaerophyllum, Daucus and Pastinaca, in warm,dry, sandy places.

Of particular interest here is the relative abundance ofspecies of Sitona, because the adults live on Fabaceaewhereas the early stages of the larvae apparently feed exclus-ively on the bacterial root nodules. Later larval stages feedon the roots themselves.

The abundance and variety of dung beetles, such asCercyon melanocephalus, Cercyon pygmaeus, Platysthethusarenarius, Trichoderma pubescens, Tachinus, Onthophagusvacca, Geotrupes, Aphodius fossor, A. rufipes and Aphodiussp. shows that these herb-rich meadows and marshes weregrazed by mammals. Some of these must have died nearby


because species such as Hister sp. and Silpha tristis, whichare both carnivorous, feed on maggots and other smallarthropods in carcasses. Trox sabulosus is necrophagous,living in dry animal remains in sandy places. Thanatophilusdispar is also necrophilous, often being found under deadfish. Phosphuga atrata is a specialist predator, catching terres-trial snails such as Helix and Succinea.

There are no obligate tree-dependent coleopteran speciesin this assemblage, which is rather surprising in the light ofthe thoroughly temperate nature of the fauna. It is likely thatany trees that were growing at this time must have been atsome distance from the sampling locality.

Samples B1 and B3

These two samples are grouped together here because theirfaunas are, in many ways, intermediate between samples B5and B6. The faunas are also small and do not permit asdetailed an environmental reconstruction as for samples B5and B6.

Aquatic habitats are represented by only three species;the dytiscid Potamonectes depressus elegans, which livesin small silt-bottomed ponds, and Helophorus grandis andHydrobius fuscipes, which both inhabit small, vegetationchoked, ponds. There are no running water species present.

Swampy vegetation is indicated by two abundant weevils,Notaris acridulus and Notaris aethiops, the former of whichfeeds principally on Glyceria and the latter on Carex andother reedy vegetation. In contrast to the fauna from sampleB5, there is an abundance of small omaliine staphylinidspecies, which live in damp vegetable debris; Olophrumfuscum, Eucnecosum brachypterum, Acidota crenata, Lestevalongelytrata, Geodromicus nigrita, Boreaphilus henningianusand Holoboreaphilus nordenskioeldi. Wet soft soil with barepatches, often by standing water, is the preferred habitat forLoricera pilicornis and Elaphrus cupreus. Areas of bare siltymud must have been available for the burrowing Heteroc-erus, which feeds on algae, and similar habitats would havesupported the abundant species of Stenus.

On rather firmer ground, species such as Bembidionbipunctatum require hard ground consisting of sandy orgravelly soil and can live either on barren banks besidestagnant or running water or where the vegetation is madeup of dense but short grasses or species of Carex (Lindroth,1992, p. 175). Calathus melanocephalus is a very eurytopicspecies for which the most important requirement seems tobe adequate exposure to the sun. It lives on a variety ofsubstrates in open country where the vegetation is meadow-like and the ground only moderately dry.

The presence of byrrhid species is significant here becausethey are exclusively moss feeders, both as adults and aslarvae. Their presence is interesting because no species ofthis family were recorded from sample B5.

Amongst the most abundant of the weevils is Otiorhynchusarcticus, which is polyphagous, feeding on a wide varietyof low herbs in moderately dry sandy habitats. In highlatitudes it is almost ubiquitous, but in Britain the speciesis found only along the western coasts or the mountains.Otiorhynchus ligneus is a rather enigmatic species becauseit is often found as a fossil in association with O. arcticus,but its present-day range does not include arctic Europe. Asboth species are nocturnal they may have problems associa-ted with the arctic summer sunlight. For example, O. arcticusis known to be able to feed on overcast days as a proxyfor genuine nightfall.

As in B5, there is evidence for the existence of dung, and


thus mammals, in the vicinity, i.e. from the presence ofHydrophilidae, Staphylinidae and the Scarabaeidae.

It is significant that the faunas from these two samplesinclude none of the phytophagous chrysomelid species socommon in the assemblage from sample B5. As most ofthese feed on low growing herbs, their absence here maybe attributed to the diminished representation of these plantsat this time.

Sample B6

The large assemblage of Coleoptera from this locality differsmarkedly from those from the other samples. One of themost distinctive features is the unique abundance of three‘non-British’ species of Helophorus; H. splendidus (193individuals), H. obscurellus (18 individuals) and H. sibericus(11 individuals). Of thse, H. splendidus and H. sibiricus livein open country in grassy ponds. Helophorus obscurellus,however, is not an aquatic species but lives in damp sandyhabitats. Further evidence of standing water comes from thedytiscids (carnivorous water beetles) Agabus congener, Ilyb-ius and Colymbetes dolabratus. Hydrobius fuscipes also livesin vegetation-rich ponds. Species of Gyrinus require opensurfaces of water on which to hund for other insects, oftentrapped there by the surface tension.

The dryopids Elmis aenea, Esolus, Oulimnius troglodytes,Limnius volckmari and Riolus collectively indicate a streamtrickling over a shallow gravelly bed, although individualsof these species can also be found on well aerated wateron the stony shores of lakes.

Wet habitats with moss and plant debris are indicated bysuch species as Cercyon marinus, C. convexiusculus, C.tristis, Cryptopleurum minutum and the abundant omaliinestaphylinids. Moss is the essential food plant of Simplocariasemistriata, S. metallica/elongata, Cytilus sericeus, Byrrhusfasciatus and Curimopsis cyclolepidia.

Marshy conditions with closed vegetation are indicatedby several of the carabid species, such as Bembidion dorisand Trechus rivularis. Moist habitats in which there arebare patches between the plants are indicated by Pelophilaborealis, Elaphrus cupreus and Loricera pilicornis. Most ofthese habitats were probably dominated by Carex, Scirpusand similar vegetation, the food source for Plateumaris ser-icea, Notaris bimaculatus, N. aethiops and Limnobaris pilis-triata. Melasoma collaris feeds exclusively on Salix in dampsandy places. Hypnoidus rivularis feeds on roots of a varietyof plants in sandy places.

Dry sandy habitats are indicated by the following carnivor-ous or scavenging carabid species. Notiophilus aquaticus,which, in spite of its name, does not require damp habitatsand lives in open country on gravelly soils, sometimes onapparently sterile habitats or in grass-rich meadows. It alsooccurs in dwarf-shrub heaths with Betula nana, where it isconstantly found in company with Amara alpina. Carabusproblematicus is xerophilous on gravelly soils in open coun-try, and in the north is often found in dwarf-shrub heaths.Amara quenseli is usually found in open country with drysandy soils where vegetation is patchy. Cymindis vapora-riorum lives on dry sandy heaths with discontinuous veg-etation, and in the high north and the mountains it is foundin association with Amara quenseli and A. alpina. Bembidiondauricum, B. fellmanni and Pterostichus middendorffi liveon dry sandy or gravelly substrates in fairly open countrywhere there is little vegetation.

The presence of dung and carcass beetles in this assem-blage has the same implication as mentioned previously.


Climatic implications of the Coleoptera

Many species in these assemblages today have restrictedgeographical ranges that leave little doubt that they arelimited by factors in the thermal climate. These species arethe most valuable in climatic reconstructions.

Sample B5

The assemblage of Coleoptera as a whole is made up ofspecies that are entirely temperate, with the northern limitsof the most restricted species reaching only as far north assouthernmost Sweden. Of the Carabidae the following spec-ies have geographical ranges that reach only as far northas southern Fennoscandia; Carabus granulatus, Bembidiondentellum, B. gilvipes, B. octomaculatum, B. obtusum, B.biguttatum, Pterostichus anthracinus, P. melanarius, Chlae-nius nigricornis and Badister bipustulatus. All these relativelysouthern species occur only in sample B5. It is importantto recognise that there are many species in this assemblagethat have widespread ranges over much of Europe andalthough many of these are able to live in arctic conditions,they do not have to. These cannot be utilised as climaticindicators. There are no obligate northerners in the assem-blage from Sample B5 (see fauna from sample B6 below forsuch species).

Using the mutual climatic range (MCR) method (Atkinsonet al., 1987) for quantifying thermal climatic conditions, thefollowing figures were obtained:

mean temperature of the warmest month(Tmax)

5 17°C to 18°C

mean temperature of the coldest month (Tmin)

5 24°C to 14°C

Sample B3

This sample would seem to span a marked climatic changebecause the coleopteran assemblage includes Chlaenius nig-ricornis, which reaches only as far north as central Fennos-candia, and Holoboreaphilus nordenskioeldi, which is a highnorthern species reaching as far west as the Kanin Peninsula.If these two species are excluded, the remainder of thisassemblage suggests a thermal climate that is cool withmean July temperatures no higher than 14°C. No attempthas been made yet to quantify these figures more precisely.

Sample B1

The assemblage here is small but includes a group of specieswith similar climatic significance to that from sample B3.Of particular interest is the occurrence of Anotylus gibbulus,the present-day range of which is restricted almost entirelyto the Caucasus Mountains. It has a fossil history, however,that is holarctic in its extent (Hammond et al 1979).

Sample B6

The climatic implications of this assemblage of Coleopteraare quite different from those inferred from any of the othersamples. The fauna is dominated by obligate cold adaptedspecies, most of which are not now living in the British Isles.


These species restricted to this sample include; Bembidionfellmanni, B. dauricum, Pterosticus middendorffi, Amara alp-ina, Colymbetes dolabratus, Ochthebius lenesis, Helophorusobscurellus, H. sibiricus, H. splendidus, Olophrum boreale,Acidota quadrata, Boreaphilus henningianus, Tachinus cael-atus, Simplocaria metallica/elongata, Curimopsis cyclolepidiaand Hippodamia arctica.

Outstanding amongst these species are: Pterostichus mid-dendorffi, which today lives no nearer than the Kola Penin-sula in Arctic Russia; Helophorus obscurellus, with a nearestpresent-day locality of the Kanin Peninsula in Arctic Russia;Helophorus splendidus (by far the most abundant species inthis assemblage), which is a northern Siberian and ArcticCanadian species that reaches as far west as the Ob delta;and Tachinus caelatus, which is confined to the Betulaforests in the mountains near Ulan Bator, Mongolia. Thesespecies leave little doubt that the climatic conditions at thetime when B6 was deposited was of arctic severity with amuch more continental climate than that of Oxfordshire atthe present day.

Using the MCR method for quantifying thermal climaticconditions, the following figures were obtained for 90% to99% of the fauna:

mean temperature of the warmest month

(Tmax) 5 7°C to 11°C

mean temperature of the coldest month

(Tmin) 5 210°C to 230°C

There is a curious anomaly amongst this assemblage of coldadapted Coleoptera; the presence of a suite of runningwater beetles, Elmis aenea, Esolus sp., Oulimnius troglodytus,Limnius volckmari, and Riolus sp. These species live in welloxygenated habitats and from their presence it may beinferred that running water was available throughout theyear, possibly beneath ice cover. Today these are not speciesof the high arctic and their presence here may indicate that,at low latitudes, shallow aquatic habitats may have beenrather warmer than those of the present-day arctic tundras.These riffle beetles, however, do not occur among the coldcontinental coleopteran assemblages of the Upton WarrenInterstadial Complex, perhaps suggesting that, by that time,winter temperatures were very much colder, interruptingtheir life cycles when their habitats were completely frozen.

Mollusca (D. H. Keen)

Fourteen samples were collected for Mollusca in Septemberand October 1991 (M1–11) and May 1994 (M12–14).Samples were usually between 5 and 10 kg wet weight,although those from the stratified sequence in Face B (M6–11) were smaller, at 2–3 kg. The samples were oven-driedat 40°C and then washed through sieves to 500 mm aperture.The collected residues were then redried and sorted.Nomenclature follows Kerney (1976) for freshwater speciesand Kerney and Cameron (1979) for land species.

The molluscan fauna

The fauna recovered from the site is listed in Table 4. Ingeneral the assemblage recovered can, with detailed differ-


ences discussed below, be divided into two. Samples M1–11, except M5, and the two samples from location 4B (M12–13) are similar in composition. The samples from M5 andfrom location 4D (M14), are slightly different from eachother, but very different from all others from the pit.

Samples M6–M11 from Face B (Fig. 2), the bulk samplesM1–M3 (Fig. 4) and those (M12 and M13) from location 4B(Fig. 6), all have high numbers of fluvial Mollusca suchas Valvata piscinalis (Muller), Bithynia tentaculata (Linne),Pisidium henslowanum (Sheppard), Pisidium nitidum Jenynsand Pisidium subtruncatum Malm. Combined values forthese species reach around 75% of the total fauna. Inaddition, the samples from 4B (M12 and M13) are rich inSphaerium corneum (Linne). Small numbers of Lymnaea spp.are common to all samples and Ancylus fluviatilis Muller arepresent in nearly all samples. The Planorbidae are relativelyuncommon and restricted to three species; Anisus leucos-toma Millet, Gyraulus laevis (Alder) and Armiger crista(Linne). Despite the abundance of debris of Unionid bivalves,particularly in samples M1–3, identifiable individuals of thisfamily are rare and only Anodonta anatina (Linne) could betentatively identified.

Land species in the fauna are few in number. The veryshelly samples (M12 and M13) provided the largest numberof species, but the numbers of individuals was highest inthe assemblages from samples M1–4 and 6–11. The landfauna is dominated by Pupilla muscorum (Linne), withTrichia hispida (Linne) and Succineidae also represented inmost samples. In addition, in samples M12 and M13, smallnumbers of Vallonia of three species occurred, together withCarychium minimum Muller.

Two samples, M5 and M14, were radically different fromthe other 12 samples described above. Sample M14 hasmany of the same species as the samples described above,but the land and marshy ground elements comprises 64%of the total fauna, with the true fluvial species restricted toless than 10% of the assemblage. Many of the fluvial andpond species in this sample show a poor state of preservationcompared with the Succineidae, P. muscorum and Lymnaeatruncatula (Muller), and it is possible that they have beenreworked from the horizons represented by samples such asM12 and M13 (4B), which are only 1–2 m below them inthe stratigraphy. The fauna contemporary to sample M14(4D) then appears to consist of marsh elements includingSuccineidae, L. truncatula, Pisidium casertanum (Poli), Pisid-ium obtusale (Lamarck) and grassland species such as P.muscorum and Vallonia spp. Sample M5 has even less ofthe fluvial assemblage and is dominated entirely by Succinei-dae and P. muscorum. Other notable records in this assem-blage are the arctic/alpine species Columella columella (vonMartens) and Vertigo genesii (Gredler).

A further, but slightly different, fauna was recovered fromthe lowest levels of the channels close to the scour pitscontaining the articulated reindeer bones (Fig. 5). The assem-blage was similar to that from M5 and M14, in that itcontained small numbers of a variety of fluvial species almostcertainly reworked from more temperate levels, together withcold marsh and grassland elements. Most notable amongthese latter were the arctic/alpine land species Vertigo geyeriLindholm, and the cold water and high-latitude bivalvePsisdium obtusale lapponicum (Clessin).

Environmental indications of the Mollusca

The local environmental indications of the molluscan faunamatch the division into the two assemblages noted above.

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Table 4 Cassington Mollusca

Species Locations unit and sample number

Face A; Face A; Face A; Face A; Face B; Face B; Face B; Face B; Face B; Face B; 48; top; 48; base Face A; 4D; 2/3;1; M1 1; M2 1; M3 1; M4 1; M6 1; M7 1; M8 1; M9 1; M10 1; M11 M12 M13 2/3; M5 M14

Valvata piscinalis (Muller) 66 35 45 62 15 27 34 30 42 392 408 5Bithynia tentaculata (Linne) 84 26 2 1 482 550 3Opercula 84 148 66 4 57 182 1Physa fontinalis (Linne) 1Lymnaea truncatula (Muller) 13 3 4 3 3 8 4 11 22 9 3 13Lymnaea stagnalis (Linne) 2 3Lymnaea peregra (Muller) 1 12 18 8 11 6 9 15 40 1Planorbis planorbis (Linne) 1 1Anisus leucostoma (Millet) 4 7 9 6 7Gyraulus laevis (Alder) 1 4 98 1 3 4 11 8 4 4 4 1Armiger crista (Linne) 1 1 1 1 10 2 1 4Planorbidae undet. 1 3Ancylus fluviatilis Muller 19 4 2 1 4 1 2 6 10Anodonta cf. anatina (Linne) 1Unionidae undet. 1 1Sphaerium corneum (Linne) 4 1 1 2 1 1 1 87 74 2 1Sphaerium lacustre (Muller) 1 1 1Pisidium amnicum (Muller) 8 2 4 1 1 1 2 13 12Pisidium casertanum (Poli) 3 2 13 4 3 3 6 8 6 4 1 2Pisidium personatum Malm 1 1Pisidium obtusale (Lamarck) 1 3

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Pisidium milium Held 1 1 1Pisidium subtruncatum Malm 50 21 65 46 7 9 27 27 21 37 24Pisidium henslowanum (Sheppard) 43 66 92 12 2 6 7 8 9 45 49Pisidium nitidum Jenyns 8 1 3 2 1 1 46 54 1Pisidium moitessierianum Paladhihe 1 1 1 1 4Pisidium tenuilineatum Stelfox 1 3Pisidium sp. 19 52 11

Carychium minimum Muller 2 5 3Oxyloma pfeifferi Rossmassler 24Succineidae undet 10 6 1 6 12 3 3 191 20Cochlicopa lubrica (Muller) 1 1Cochlicopa sp. 1Columella columella (von Martens) 20Vertigo pygmaea (Draparmaud) 1Vertigo genesii (Gredler) 1 2 1Vertigo sp.Pupilla muscorum (Linne) 2 1 7 196 25 76 193 171 145 16 17 125 11Vallonia costata Muller) 1 1Vallonia pulchella (Muller) 3 4 10Vallonia enniensis (Gredler) 1Vallonia sp. 2 12Nesovitrea hammonis (Strom) 1Limax sp. 2Euconulus fulvus (Muller) 1Trichia hispida (Linne) 2 11 7 7 2 26 6 4

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The serial samples from Face B (M6–M11), samples M1–3from Face A and those from 4B (M12 and M13) formingone group (i), with samples from M5 (Face A) and M14(4D) being quite different (ii).

The majority of the species in group (i) are from fluvialhabitats. The almost constant occurrence of Ancylus fluviat-ilis Muller in the samples from this group confirm thisbecause this species is a fluvial obligate in British lowlandenvironments (Kerney, 1971). The large numbers of V. pis-cinalis and B. tentaculata, and the ‘moving water’ group ofPisidium (P. henslowanum and P. subtruncatum) also indi-cate fluvial conditions. The fall in values for B. tentaculataupwards in the serial samples could be due to more vigorousconditions in the river, as this species appears to preferpools and slow-moving reaches rather than main channel,but the continuation of good numbers of A. fluviatilis andV. piscinalis in the serial samples also suggest this. Thegreater stream action perhaps indicates that a regional cli-matic cause may be invoked to account for this fall innumbers. The low numbers for Planorbidae suggest thatthere was little of the macrophytic vegetation required bythese taxa.

The land environment was dominated by marsh and grass-land. The most numerous land snail in all the samples ofthis group is P. muscorum, an inhabitant of dry grassland(Kerney and Cameron, 1979). The local environment indi-cated by the samples taken from the basal units of thesequence at Cassington was one of a flowing river, perhapswith pools, but not much macrophytic vegetation. The landareas along the river were under grassland and marsh. Thereis no indication of shaded habitats from the Mollusca,although some scrub could have been present.

Sample M14 from group (ii) has little evidence of fluvialconditions, especially if the probable reworked elements arediscounted. Instead, the Mollusca indicate an environmentof marsh and grassland, with a few pools or other smallstanding water bodies. The very low diversity fauna fromthe M5 also indicates this type of local environment.

Climatic implications of the Mollusca

Some inference concerning the regional climate can bemade. The samples from the basal layers indicate a regionalclimate that was not much different from that of the presentday. Most of the freshwater taxa present have a wide geo-graphical range in Europe at present (Kuiper et al., 1989;Okland, 1990), but such species as Anodonta anatina (Linne)and Pisidium moitessierianum Paladilhe occur only as farnorth as the south of Scandinavia (Ellis, 1978), indicatingthat the climate at the time of deposition was cool temperate.The low numbers of the thermophile P. moitessierianum,however, suggest that water temperature may have beenslightly lower than at present in central England. The absenceof thermophiles such as Belgrandia marginata (Michaud),common in full interglacial fluvial deposits in southernEngland and the Midlands (Keen, 1990; Maddy et al., 1991)also suggests that the most temperate conditions at Cassing-ton were not as warm as those of the thermal maximum ofthe Ipswichian interglacial.

The land fauna is similarly undemanding in its climaterequirements, but several taxa in it have limited northernranges at present (Kerney and Cameron, 1979). In particular,Carychium minimum Muller, Trichia hispida (Linne) andVallonia costata (Muller) can be found only as far north asthe Arctic Circle at the Norwegian coast, and have more


southerly limits inland. Vertigo pygmaea (Draparnaud)reaches around only 62°N in Scandinavia along the coastalfringe of Norway and Sweden, and has its core distributionin the south of Sweden (Scania) and further south in Europe.Thus the climate indicated by the total molluscan faunafrom the basal layers is temperate, not much different fromthat of present-day Oxfordshire. A further indicator of climateis the lack of any woodland obligates among the land fauna.This may suggest that woodland was restricted to scrub orscattered woods away from the main water courses, or thattrees were scarce due to climatic dryness, which wouldfavour grassland over tree growth. A very similar molluscanassemblage to that at Cassington, from Isleworth in WestLondon, is suggested by Kerney et al. (1982) to indicatesummer temperatures were no lower than 15°C, althoughthis is dated to the Upton Warren Interstadial of inferredMiddle Devensian age.

The samples from higher in the gravels than the basallevels show evidence of colder conditions. There are slightlydifferent indications from the two samples M5 and M14.The sample M5 has small numbers of individuals of up to15 freshwater taxa. Only L. truncatula has more than 10specimens in the sample. The land fauna is similar to thebasal samples in species present, but only Oxyloma pfeifferiRossmassler, other unidentified Succineidae, P. muscorumand Vallonia sp. are present in numbers greater than 10.Together these five taxa represent 64% of the molluscantotal. The small number of taxa that represent the majorityof the shells in the sample have a wide distribution inEurope, most reaching as far north as northern Scandinaviaat present. This rather tolerant fauna is indicative of con-ditions of some climatic severity, although it is lackingmembers of the true Arctic/Alpine fauna. A similar assem-blage from Beckford, Worcestershire was thought by Briggset al. (1975) to indicate summer temperatures of below10°c and mean annual temperatures of 26° to 28°C. Suchconditions would also be likely for the sample from theReindeer scour hole.

Sample M5 is even more restricted, being composed ofonly seven taxa, of which P. muscorum and Succineidaemake up 90% of the assemblage. In addition, the fauna ofM5 contains two of the very few species of arctic/alpineMollusca present in Europe, C. columella and V. genesii. Itis probable that this restricted assemblage represents con-ditions of full arctic severity, with analogues in modernEurope in the tundra of the northermost limits of the conti-nent. Further evidence of the severity of the climate iscontained in the form of P. muscorum present. All the shellsare of the tall, highly cylindrical form first recorded fromthe Devensian Late-glacial of Kent by Kerney (1963) andregarded by him as the typical full-glacial morphotype ofthis species. By contrast specimens of P. muscorum insamples other than M5 and M14 are smaller and less cylin-drical, similar to modern specimens from the Downsaround Newbury.

Thus the succession at Cassington shows evidence ofprogressive climatic deterioration from the basal layers intothe overlying units, with sample M14 representing coldconditions and M5 being colder still and at the limit of snailexistence in true tundra.

Small vertebrate remains (S. Parfitt)

Five bulk samples (V1–5) for the recovery of small vertebrateswere collected from association B. Approximately 40 kg (V1–


3) and 66 kg (V4 and V5) were processed by wet-sievingthe samples through a 1 mm mesh. The residues were driedand floated in water, which assisted in the removal oforganic detritus, the heavy fraction that remained after flo-tation was then sorted for small vertebrates.

With the exception of sample V3, bones were scarce andno identifiable material was present in sample V1. The smallvertebrate fauna, listed in Table 5, is not particularly diverse,nevertheless the assemblage provides some information onthe palaeoenvironment during the deposition of this associ-ation.

Fish remains (pharyngeal teeth, vertebrae and other boneelements) predominate in sample V3, with most of the cypri-nid fishes being represented by young individuals. The com-position of the fish fauna is indicative of standing or slowlyflowing well-oxygenated freshwater, with areas of rocky orsandy substrate and a rich aquatic invertebrate fauna. Rela-tively gentle sedimentary conditions are indicated by thecondition of the vertebrate remains, which suggest minimalpost-mortem fluvial transportation and relatively rapid burial.The occurrence of fragile specimens, such as the pharyngealbones of cyprinid fishes that retain their teeth and an articu-lated spine and scute of Gasterosteus aculeatus (three-spinedstickleback), would rule out the possibility that the remainsare reworked from earlier deposits and is evidence of avery low-energy depositional environment. The vertebrateassemblage therefore represents an autocthonous assemblagethat accumulated in a quiescent stream or pond. Rana tem-poraria (common frog) occupies terrestrial habitats outsidethe breeding season, when it may be found in a wide rangeof environments providing they are damp and within closeproximity to water. Damp grassland is indicated by Microtusoeconomus (northern vole), the only species of small mam-mal present. Today the northern vole is widely distributed

Table 5 Vertebrate faunal list. Small vertebrate faunal remains recovered from fine-grained facies (association B), largemammal remains from scour hollows (association B) and from gravel deposits (association D and E)

Sample

V2 V3 V4 V5

Fish Gasterosteus aculeatus Linne (three- 2 1 2 2spined stickleback)Gobio gobio (Linne) (gudgeon) 2 1 2 2Alburnus alburnus (Linne) (bleak) 2 1 2 2Leuciscus leuciscus (Linne) (dace) 2 1 2 2Anguilla anguilla (Linne) (eel) 2 2 1 2Indeterminate fish 1 2 2 2

Amphibian Rana temporaria Linne (common frog) 2 1 2 2Rana sp. (frog) 2 2 1 2Anuran indet. 2 1 1 1

Bird Indeterminate bird 2 1 2 2Small mammal Microtus oeconomus (Pallas) (northern 2 1 2 2

vole)Microtine rodent 2 2 2 1

Large Mammuthus primigenius Blumenbach (woolly mammoth)mammals Bison priscus Bojanus (bison)(general finds Rangifer tarandus Linne (reindeer)from associations A & Coleodonta antiquitatis Blumenbach (woolly rhinoceros)B)

Equus sp. (horse)Ursus arctos Linne (bear)Canis lupus Linne (wolf)


across the tundra and coniferous and temperate mixed forestzones of northern Eurasia. It is particularly common inmarshy grasslands, fens, bogs and the banks of small streams,although it may also live in dry grasslands when there isno competition from other microtine rodents (Macdonaldand Barrett, 1993).

The climatic conditions during the deposition of thesesediments can be inferred from the modern distribution ofthe species represented in sample V3. In this respect thecyprinid fishes are particularly useful indicators of climaticconditions, as their present-day range is largely governed bysummer temperature (Wheeler, 1977). Although Leuciscusleuciscus (dace), Alburnus alburnus (bleak) and G. aculeatus(three-spined stickleback) occur throughout most of westernEurope up to or well within the Arctic Circle, Gobio gobio(gudgeon) has a southern distribution and occurs no furthernorth than southern Sweden (Muus and Dahlstrom, 1971;Stuart, 1982). The presence of gudgeon implies that summertemperatures during the deposition of the upper organic richsilts were at least as warm as those of south Fennoscandiaat the present day.

The presence of cyprinid fish in this stratigraphic contextat Cassington is of some biogeographical interest. Wheeler(1977) has argued on physiological grounds that the primaryfreshwater fishes of the British Isles were absent during theDevensian because they require warm summer temperaturesfor successful reproduction. The fish assemblage from Cas-sington includes three species of cyprinid fishes, evidencethat cyprinids were able to recolonise British river systemssuch as the upper reaches of the Thames from their refugesin the south during the warmer phases of the last cold stage.


Large vertebrates (T. Hardaker and K. Scott)

Since the opening of the gravel pit at Cassington in mid-1989, regular visits have been made (almost weekly) tocollect mammalian fauna. Although a total of almost 1000bones has been recovered this must represent only a smallfraction of the total fauna. Large vertebrate remains havebeen recovered, in the main, from associations A and B,with over 90% of the finds coming from this level. Sporadicfinds of reworked remains have also been recovered fromassociations D and E.

The fauna recovered comprises seven species identifiedfrom bones, teeth and antlers (Table 5). Although only two-thirds of the fauna recovered has, to date, been conservedand identified, some comments can be made about speciesrepresentations, which are believed to hold true for therest of the assemblage. Equus ferus (horse) and Coelodontaantiquitatis (woolly rhino) are each represented by onlythree items, and Mammuthus primigenius (mammoth) by acomplete lower jaw, several teeth and bones and a fewfragments of tusk. The condition of preservation of theseelements (they are paler in colour and less well-preservedthan the rest of the fauna) suggest that they originated inthe overlying sands and gravels. The rest of the large ver-tebrate fauna, apart from a bone and a tooth of Canis lupus(wolf) and the limb bone of Ursus arctos (brown bear), isentirely of Rangifer tarandus (reindeer) and Bison priscus(bison).

Concentrations of bones tend to occur in depressions,which most probably represent scour hollows into whichdebris was swept. The conditions of the bones in thesesediments is exceptionally good. Unfortunately the necessityto collect rather than excavate systematically has resulted,generally, in the biased representation of large (i.e. mostvisible) remains. Thus the bison is represented by horns andlarge limb bones, and the reindeer overwhelmingly by ant-lers, with smaller bones virtually absent. The likelihood thatthese two species were represented by many more body-parts and that there had been relatively little post-depos-itional disturbance is borne out by the results of an exca-vation that was possible in the far east of the pit (Fig. 5).Here 110 bones of bison and reindeer (and one wolf tooth)were scattered over the bed of a scour hollow. Of particularinterest were the bones lodged on the lee side of threeseptarian nodules (Fig. 5). Among these bones was a beauti-fully preserved bison vertebra and the articulated hind legof a reindeer with every tarsal in place. It would appearthat the septaria lay in the channel protecting these bones,thus accounting for their mint condition.

Another concentration of bones was found embedded inweathered peaty clay. This comprised 22 reindeer ribs and4 vertebral spines in an area 3 3 1.5 m. Three of the ribsare virtually complete and the rest fragmentary. The fourvertebrae are fractured at the centrum junction in exactlythe same way. This curious assemblage perhaps representsthe carcass of a single animal, the torso of which hadbecome detached from the rest of the skeleton. It is possiblethat carnivores may have achieved this but, despite theexcellent state of preservation of these remains, no evidenceof gnawing can be found.

Faunas dominated by bison and reindeer are known fromother British localities, e.g. Wretton (West et al., 1974) andPicken’s Hole (ApSimon, 1986), where their association withevidence for cool but not very cold climatic conditions andthe presence of woodland has led to suggestions of an earlyDevensian interstadial age for the faunas. Whether they were


confined to the interstadials or characterised most of theperiod from the end of the Ipswichian until the cold con-ditions developed later in the Devensian has yet to beestablished. However, a study of British cave faunas (Scott,1986) suggests that at stratified sites such as Picken’s Holeand Cassington, a fauna dominated by herds of mammoth,woolly rhino and horse, preyed upon by spotted hyaena,and associated with open steppe–tundra conditions, did notreplace the earlier reindeer–bison fauna, with woodlandassociations and lacking mammoth, rhino, horse and hyaena,until the Middle Devensian.

From the gravels (associations D and E) the only boneretrieved in situ was a well-preserved horse astragalus. Therest of the material (small quantities of mammoth, woollyrhino, horse and reindeer) were retrieved from reject heapsbut, from their colour and varying degrees of abrasion it isprobable that they were originally contained within thegravels and therefore associated with a colder depositionalenvironment than was the case for the basal fauna.

Aminostratigraphy (D. Q. Bowen)

D-aIle/L-Ile ratios from six samples of Bithynia tentaculataand five samples of Valvata piscinalis from association B(sample M1, Fig. 4) were analysed using the proceduresdescribed in Bowen et al. (1985) (Table 6). The V. piscinalisD-aIle/L-Ile ratio of 0.136 6 0.009 (5) is somewhat higherthan the standard Ipswichian (substage 5e) D-aIle/L-Ile ratioof 0.09 6 0.01 proposed earlier (Bowen et al., 1989); butcorresponds to an earlier of two characteristic D-aIle/L-Ilefor marine gastropods (Littorina standard) proposed for subst-age 5e: 0.15 and 0.11 (Bowen, 1994a, b). Thus, becauseboth non-marine gastropods and the Littorina group of mar-ine gastropods appear to epimerise as ‘slow’ rates (cf. Millerand Mangerud, 1985; Bowen et al., 1985, 1989), the V.piscinalis D-aIle/L-Ile ratios of 0.136 indicate an age earlier,rather than later in the Ipswichian (substage 5e).

The younger B. tentaculata D-aIle/L-Ile ratios of 0.081 60.009 (6) are intermediate between those of 0.135 (earlysubstage 5e) and 0.066 6 0.007 (5) correlated with substage5a (‘Upton Warren’) by Bowen et al. (1989), thus may notunreasonably overlap with substage 5c.

Table 6 Amino acid results on Bithynia tentaculata and Valvatapiscinalis from Cassington

Bithynia tentaculata Valvata piscinalis

ABER1119A 0.079 ABER1120A 0.14ABER1119B 0.094 ABER1120B 0.125ABER1119C 0.081 ABER1120C 0.148ABER1119D 0.09 ABER1120D 0.126ABER1119E 0.075 ABER1120F 0.141ABER1119F 0.069

Mean 0.081 0.136SD 0.009 0.009n 6 5


OSL age estimation (J. Rees-Jones)

Samples were taken from two levels within association B(865b,c) and one from association C (865a), Face B (Fig. 2).The samples were treated with dilute hydrochloric acid andhydrogen peroxide, rinsed in distilled water and sieved toseparate the 90–125 mm grains. Quartz was separated fromthese grains by using liquid density separation (sodium poly-tungstate solutions of 2.58 and 2.70 g cm23). The grainswere further treated by a 40% solution of hydrofluoric acidfor 40 minutes in order to remove the outer layer exposedto alpha irradiation. The grains were resieved and depositedon to stainless steel discs using Silkospray silicone oil asan adhesive.

The luminescence signal from the quartz was measuredusing 514 nm light from an argon ion laser (Huntley et al.,1985). Aliquots were normalised by the counts producedfrom a short shine applied to the natural signal. Additivebeta growth curves were constructed using a Sr90–Y90 sourcefor irradiation. A preheat of 5 minutes at 220°C was usedto remove the luminescence signal unstable over the burialperiod. The palaeodose received by the quartz was deter-mined by fitting a saturating exponential function to thegrowth curves.

The annual radiation dose received by the samples wasdetermined by on-site gamma spectrometry.

Results and discussion

The measured values for the palaeodose rates are shown inTable 7, together with the dates calculated. The errors quotedare at the 68% confidence level and include both randomand systematic errors (Aitken, 1985). The dates of 80–136 kaagree with the amino acid dates for the site and are instratigraphic agreement. Layer 865c appears older than layers865a and b, which overlap substantially at these confidencelimits. These dating results would place the temperate inter-val indicated by the organic deposits in Oxygen IsotopeStage 5.

Discussion

The information presented above allows a consistent patternof major environmental changes to be identified. Changingcoleopteran and molluscan faunas indicate a deteriorationfrom temperate through to arctic climatic conditions. Tem-perature estimates based upon the coleopteran assemblagessuggests mean July temperatures during the warmer phasewere 17° to 18°C, with mean January–February temperatures

Table 7 Optically stimulated luminescence results from Cassington

Sample Palaedose Annual dose Age (ka)(Gy) rate

(Gy ka21)

Top 865a 135 6 34 1.74 6 0.06 58–87Middle 865b 163 6 35 1.95 6 0.06 65–102Base 865c 172 6 32 1.38 6 0.05 101–148


in the range 24° to 14°C (sample B5), whereas July tem-peratures no higher than 14°C are suggested by the assem-blage from sample B3, which lies close to the transitionfrom sedimentary associations B to C. Further up thesequence, extreme cold conditions are suggested by meanJuly temperatures of 7° to 11°C and mean January–Februarytemperatures in the range 210° to 230°C (sample B6).Similar temperatures are suggested by the molluscan fauna.The floral data shows a less marked deterioration but never-theless indicates a change from open forest to tundra typevegetation.

The deterioration in climate suggested by the biostrati-graphical data appears to coincide with the change in fluvialstyle recorded in the transitions through sedimentary associ-ations A–D. These sedimentological changes indicate a tran-sition from a single thread to multithread channel system,which reflects changing sediment and/or discharge con-ditions. The apparent increase in sediment supply, suggestedby the increased volume of sediment deposited on thefloodplain, may be a consequence of slope instabilityresulting from the changing vegetation cover. Climaticdeterioration may reflect changes in atmospheric circulationpatterns, specifically the frequency of depressions over south-ern Britain, resulting in an increase in flood frequency andmagnitude. Changing seasonality may also lead to the devel-opment of freeze–thaw cycles, thus enhancing weatheringand erosion processes. These adjustments in sediment supplyand discharge as climate deteriorates is manifested inswitches between positive and negative sediment budgets,resulting in aggradation or degradation of the floodplain(Fig. 10).

The chronology of these changes is also summarised inFig. 10. The age estimates from amino acid (AA) epimer-isation and optically stimulated luminescence (OSL) are inclose agreement and suggest correlation of associations Aand B, at least in part, with Oxygen Isotope Stage 5. TheAA data from the basal sediments suggest attribution of thispart of the sequence to Oxygen Isotope Substages 5e–5c.The stratigraphically lowest OSL estimate (865c) also sup-ports this correlation (Fig. 10). Based upon the OSL geoch-ronology from the higher levels (865b and 865a), the bulkof associations B and C may relate to the latter part ofOxygen Isotope Stage 5. Given the uncertainties surroundingluminescence signal zeroing in fluvial environments, the OSLestimates should perhaps be viewed as maximum ages mak-ing it likely that the bulk of these dated sediments relate tothe latter half of Stage 5, and a correlation with oxygenIsotope Substage 5a seems the most plausible attribution.On this basis it seems reasonable to suggest that the majorenvironmental change recorded at this site relates to theOxygen Isotope Stage 5–4 transition.

Within this chronological framework the biostratigraphicaldata from Cassington may be compared with the strati-graphical scheme for the UK during this period (Jones andKeen, 1993). The earliest biological data from Cassington isinconclusive regarding the age of this part of the sequence.The tentative correlation with the Ipswichian (5e) on thebasis of the geochronology cannot be confirmed by biostrati-graphical correlation with known Ipswichian sites. Tempera-ture reconstruction from the Coleoptera in sample B5, how-ever, suggest that such a correlation is possible for this partof the sequence only. Correlation of the Cassingtonsequence, at least in part, with Substage 5c may also beproblematic because the coleopteran fauna from all thesamples differ significantly from those at Chelford (Coope,1959; Simpson and West, 1958), where the Chelford inter-stadial stratotype sequence has been correlated with Oxygen


Figure 10 Summary of OSL and amino acid data from Cassington and timing of changes in fluvial activity inferred from sedimentologyand geochronological information.

Isotope Substage 5c on the basis of OSL age estimates(Rendell et al., 1991).

The palynology from the basal samples at Cassingtonindicates an open boreal forest vegetation. The presence oftree taxa excludes a correlation with the Upton WarrenInterstadial Complex (Coope et al., 1961). Although thevegetation is broadly similar to that recorded at Chelford, acorrelation with Chelford can also be excluded on the basisof the Coleoptera, as noted above. However, in contrast tothe flora, the rather varied molluscan faunas from the basalsediments at Cassington fit well with those described asUpton Warren Interstadial in age from elsewhere in theBritish Isles (Holyoak, 1982). Similar faunas have beendescribed from elsewhere in the Thames catchment, noteablyfrom Isleworth, West London; (Kerney et al., 1982) andKempton Park, Sunbury (Gibbard et al., 1982) and from theGreat Ouse valley (Rogerson et al., 1992). Radiocarbon datesof 43 140 1 1520/21280 yr BP (Birm-319) from Isleworth,43 250 12010/21610 yr BP (SRR-2980) and 40 50011380/21180 yr BP (SRR-2981) from Radwell, led to thecorrelation of these sites with the Middle Devensian UptonWarren Interstadial of Coope et al. (1961). However, theidentification of the wood on which the Radwell dates wereobtained as Abies, generally regarded as an interglacialspecies, led Rogerson et al. (1992) to treat these dates asminimum values.

A possible correlation of the Cassington sequence withthe Upton Warren Interstadial Complex on the basis of theMollusca but refuted by the pollen, is also contradicted bythe correlation of the coleopteran fauna from sample B6with similar assemblages from the Ismaili Centre, SouthKensington, London (Coope et al., in press), which lie strati-graphically below the distinctive Upton Warren type faunalassemblage. This correlation, together with the marked floral


differences between Cassington and Upton Warren, suggeststhat the biostratigraphical data from Cassington reported herepre-dates the Upton Warren Interstadial Complex, which hasbeen attributed, on the basis of stratigraphy, palynology andradiocarbon age estimates (Coope et al., in press), to OxygenIsotope Stage 3, suggesting that all the sediments underlyingand including the cold climate organic beds within associ-ation D were deposited prior to Oxygen Isotope Stage 3.This conclusion is also supported by the restricted mam-malian fauna, which comprises an assemblage typical of theEarly rather than Middle Devensian. In this respect theCassington deposits are similar to the Early Devensiandeposits at Wretton (Sparks and West, 1968; West et al.,1974).

Thus taken as a whole, the biostratigraphical data fromfacies associations A and B cannot readily be correlatedprecisely with existing well constrained Late Pleistocenesequences in the UK. The arguments presented aboveexclude correlation of this sequence with the Ipswichianinterglaial (Oxygen Isotope Substage 5e), the Chelford Inter-stadial (Oxygen Isotope Substage 5c) or the Upton WarrenInterstadial Complex (Oxygen Isotope Stage 3). Using thegeochronology the temperate episode represented at Cassing-ton offers the prospect of defining a previously unrecognisedevent in the British Early Devensian record; the ‘Cassingtoninterstadial’. This may best be correlated with Oxygen Iso-tope Substage 5a. Sediments from this time period have notyet been widely recognised in the British Isles, althoughpreviously described localities may belong in this period.

A major objective of this investigation was to examinethe nature of fluvial activity associated with climatic changesduring the last interglacial–glacial transition. The sedimentol-ogy, together with the biological and chronological infor-mation, indicates that a major change in fluvial style occurs


as a consequence of climatic deterioration. Deposition dur-ing the latter part of Oxygen Isotope Stage 5 is characterisedby a predominantly low energy regime in a meanderingriver (associations A and B). Transition to a high energy,braided river occurs at the oxygen Isotope Stage 5a–4 tran-sition, and most of the gravels of association D weredeposited during Oxygen Isotope Stage 4. This may suggestthat a large part of the sediment body that comprises theNorthmoor Member was deposited during the Early Deven-sian (Oxygen Isotope Stage 4), and that little depositionalactivity took place during the latter part of the Devensianin this part of the valley (Fig. 10). This is in contrast to theviews of Briggs et al. (1985), who suggested that the bulkof this sediment body was deposited during the Late Deven-sian (i.e. Oxygen Isotope Stage 2).

The significance and timing of the change from associ-ations D to E remains problematic and no geochronology ispresently available. Intraformational ice wedge casts on thebounding surface beneath association E confirm that depo-sition took place under cold climate conditions. However,it is unknown what temporal hiatus, if any, exists betweendeposition of the two associations, although a Late Deven-sian age is considered likely for association E (Fig. 10).

The biostratigraphical data is largely restricted to fine-grained deposits, in particular association B, reflectingenhanced preservation potential in these low-energy environ-ments. The lack of biological data elsewhere in the suc-cession does therefore not allow a complete reconstructionof palaeoclimate for the entire period represented by thesesediments. However, the change in river activity does indi-cate changing basin conditions, allowing considerable infer-ence to be made concerning environmental conditions forthe periods not represented in the biological record. Such acombination of studies serves to emphasise the importanceof a multidisciplinary approach to investigating these fluvialarchives. Furthermore the apparent success of the geochrono-logical methods used in establishing a chronology for thesedeposits provides new impetus for the investigation of similarsequences. The dating of numerous cold-climate organiclevels within the sequence of the Upper Thames valley mayprovide the key to obtaining a higher resolution record ofenvironmental change, inviting the correlation of events withthose recorded in the high-resolution ice-core records.

Acknowledgements The authors would like to thank Mr Bob Turner(Pit Manager, ARC Cassington) for his enthusiastic support and forallowing continued access to the pit. DM and SGL would like toacknowledge the support of NERC (GR9/01656) while undertakingpart of this work and in particular the help and encouragement ofDr Neville Hollingworth. DHK would like to acknowledge workundertaken at Coventry University by Ms E. L. Etwaroo. We wouldalso like to thank the two referees Dr David Bridgland and DrPhil Gibbard for useful critical comments on an earlier version ofthis paper.

References

AITKEN, M. J. 1985. Thermoluminescence Dating. AcademicPress, London.

ALLEN, J. R. L. 1963. The classification of cross-stratified units, withnotes on their origin. Sedimentology, 2, 93–114.

ApSIMON, A. M. 1986. Picken’s Hole, Compton Bishop, Somerset.IN: Collcutt, S. N. (ed.), The Palaeolithic of Britain and its NearestNeighbours: Recent Trends. University of Sheffield.

ARKELL, W. J. 1947. The Geology of Oxford. Clarendon Press,Oxford.


ATKINSON. T. C., BRIFFA, K. R. and COOPE, G. R. 1987. Seasonaltemperatures in Britain during the past 20 000 years, reconstructedusing beetle remains. Nature, 325, 587–592.

BELL, F. G. 1969. The occurrence of southern, steppe and halophyteelements in Weichselian (last-glacial) floras from southern Britain.New Phytologist, 68, 913–922.

BELL, F. G. 1970. Late Pleistocene floras from Earith, Huntingdon-shire. Philosophical Transactions of the Royal Society of London,B258, 347–378.

BENNETT, K. D., WHITTINGTON, G. and EDWARDS, K. J. 1994.Recent plant nomenclatural changes and pollen morphology inthe British Isles. Quaternary Newsletter, 73, 1–6.

BLUCK, B. J. 1971. Sedimentation in the meandering River Endrick.Scottish Journal of Geology, 7, 93–138.

BOND, G., BROECKER, W., JOHNSEN, S., McMANJUS, J., LABERY-RIE, L., JOUZEL, J. and BONANI, G. 1993. Correlation betweenclimate records from North Atlantic sediments and Greenland ice.Nature, 365, 507–508.

BOULTON, G. S. 1993. Two cores are better than one. Nature,366, 507–508.

BOWEN, D. Q. 1994a. Late Cenozoic Wales and South WestEngland. Proceedings of the Ussher Society, 8, 209–213.

BOWEN, D. Q. 1994b. Double 5e sea-level event in the BritishIsles. Eos (American Geophysical Union, Spring MeetingSupplement), 208.

BOWEN, D. Q., SYKES, G. A., MILLER, G. H., ANDREWS, J. T,BREW, J. S. and HARE, P. E. 1985. Amino-acid geochronologyof raised beaches in south west Britain. Quaternary ScienceReviews, 4, 279–318.

BOWEN, D. Q., HUGHES, S., SYKES, G. A. and MILLER, G. H.1989. Land–sea correlations in the Pleistocene based on iso-leucine epimerization in non-marine molluscs. Nature, 340, 49–51.

BOWEN, D. Q., McCABE, A. M., SUTHERLAND, D. G., BRIDG-LAND, D. R., CAMERON, T. D. J., CAMPBELL, S., GIBBARD, P.L., HOLMES, R., LEWIS, S. G., MADDY, D., PREECE, R. C. andTHOMAS, G. S. P. in press. Correlation of Quaternary Depositsin the British Isles. Geological Society of London, Special Report.

BRIDGLAND, D. R. 1994. Quaternary of the Thames. GeologicalConservation Review Series No. 7 Chapman and Hall, London.

BRIGGS, D. J. and GILBERTSON, D. D. 1973. The age of theHanborough terrace of the River Evenlode, Oxfordshire. Proceed-ings of the Geologists’ Association, 84, 155–73.

BRIGGS, D. J., COOPE, G. R. and GILBERTSON, D. D. 1975. LatePleistocene terrace deposits at Beckford, Worcestershire, England.Geological Journal, 10, 1–16.

BRIGGS, D. J., COOPE, G. R. and GILBERTSON, D. D. 1985. Thechronology and environmental framework of early man in theUpper Thames Valley: a New Model. British Series 137, BritishArchaeological Reports, Oxford.

BRYANT, I. D. 1983. The utilisation of Arctic river analogue studiesin the interpretation of periglacial river systems in southern Britain.IN: Gregory, K. J. (ed.), Background to Palaeohydrology: a Per-spective, 413–431. John Wiley & Sons, London.

COOPE, G. R. 1959. A Late Pleistocene insect fauna from Chelford,Cheshire. Proceedings of the Royal Society of London, B151,70–89.

COOPE, G. R. 1986. Coleoptera analysis. IN: B. E. Berglund (ed.)Handbook of Holocene Palaeoecology and Palaeohydrology, 703–713. J. Wiley & Sons, Chichester.

COOPE, G. R., SHOTTON, F. W. and STRACHAN, I. 1961. A LatePleistocene fauna and flora from Upton Warren, Worcestershire.Philosophical Transactions of the Royal Society of London, B244,379–421.

COOPE, G. R., MORGAN, A. and OSBORNE, P. J. 1971. FossilColeoptera as indicators of climatic fluctuations during the LastGlaciation in Britain. Palaeogeography, Palaeoclimatology,Palaeoecology, 10, 87–101.

COOPE, G. R., GIBBARD, P. L., HALL, A. R., PREECE, R. C.,ROBINSON, J. E. and SUTCLIFFE, A. J. in press. Climatic andenvironmental reconstructions based on fossil assemblages fromthe Middle Devensian (Weichselian) deposits of the River Thames


at South Kensington, Central London. Quaternary ScienceReviews.

DANSGAARD, W., JOHNSON, S. J., CLAUSEN, H. B., DAHL-JENSEN, D., GUNDESTRUP, N. S., HAMMER, C. U., HVIDBERG,C. S., STEFFENSEN, J. P., SVEINBJORNSDOTTIR, A. E., JOUZEL,J. and BOND. G. 1993. Evidence for general instability of pastclimate from a 250-kyr ice-core record. Nature, 364, 218–220.

ELLIS, A. E. 1978. British Freshwater Bivalve Mollusca. LinneanSociety Synopses of the British Fauna No. 11, Academic Press,London.

GIBBARD, P. L., COOPE, G. R., HALL, A. R., PREECE, R. C. andROBINSON, J. E. 1982. Middle Devensian deposits beneath the‘Upper Floodplain’ terrace of the River Thames at Kempton Park,Sunbury, England. Proceedings of the Geologists’ Association, 93,275–289.

GOUDIE, A. S. 1976. Introduction: The Oxford Region. IN: Roe,D. (ed.), Field Guide to the Oxford Region, 1–5. QuaternaryResearch Association.

HAMMOND, P. M., MORGAN, A. and MORGAN, A. V. 1979. Onthe gibbulus Group of Anotylus, and the fossil occurrences ofAnotylus gibbulus. (Staphylinidae). Systematic Entomology, 4,215–221.

HOLYOAK, D. T. 1982. Non-marine Mollusca of the Last GlacialPeriod (Devensian) in Britain. Malacologia, 22, 727–730.

HUNTLEY, D. J., GODFREY-SMITH, D. I. and THEWALT, M. L. W.1985. Optical dating of sediments. Nature, 313, 105–197.

JONES, R. L. and KEEN, D. H. 1993. Pleistocene Environments inthe British Isles. Chapman and Hall, London.

KEEN, D. H. 1987. Non-marine molluscan faunas of periglacialdeposits in Britain. IN: Boardman, J. (ed.), Periglacial Processesand Landforms in Britain and Ireland, 257–263. Cambridge Uni-versity Press, Cambridge.

KEEN, D. H. 1990. Significance of the record provided by Pleisto-cene fluvial deposits and their included molluscan fauna forpalaeo-environmental reconstruction and stratigraphy: case studiesfrom the English Midlands. Palaeogeography, Palaeoclimatology,Palaeoecology, 80, 25–34.

KERNEY, M. P. 1963. Late-glacial deposits on the Chalk of south-east England. Philosophical Transactions of the Royal Society ofLondon, B246, 203–254.

KERNEY, M. P. 1971. Interglacial deposits at Barnfield Pit, Swan-scombe, and their molluscan fauna. Journal of the GeologicalSociety of London, 127, 69–93.

KERNEY, M. P. 1976. A list of the fresh and brackish water Molluscaof the British Isles. Journal of Conchcology, 29, 26–28.

KERNEY, M. P. and CAMERON, R. A. D. 1979. A Field Guide tothe Land Snails of Britain and north-west Europe. Collins, London.

KERNEY, M. P., GIBBARD, P. L., HALL, A. R. and ROBINSON, J. E.1982. Middle Devensian river deposits beneath the ‘Upper Flood-plain’ terrace of the River Thames at Isleworth, West London.Proceedings of the Geologists’ Association, 93, 385–393.

KUIPER, J. G. J., OKLAND, K. A., KNUDSEN, J., KOLI, L. VONPROSCHWITZ, T. and VALOVIRTA, I. 1989. Geographical distri-bution of the small mussels (Sphaeriidae) in North Europe(Denmark, Faroes, Finland, Iceland, Norway and Sweden).Annales Zoologici Fennici, 26, 73–101.

LARSEN, E., SEJRUP, H. P., JOHNSEN, S. J. and KNUDSEN, K. L.1995. Do Greenland ice cores reflect NW European interglacialclimate variations? Quaternary Research, 43, 125–132.

LICHTI-FEDEROVICH, S. and RITCHIE, J. C. 1968. Recent pollenassemblages from the western interior of Canada. Review ofPalaeobotany and Palynology, 7, 297–344.

LINDROTH, C. H. 1992. Ground Beetles (Carabidae) of Fennoscan-dia, a Zoogeographical Study. Part 1 (English translation of theGerman original). 1–630. Intercept, Andover, Hampshire, U.K.

LUCHT, W. H. 1987. Die Kafer Mitteleuropas, Katalog, 1–342.Goecke and Evers, Krefeld.

MacDONALD, D. W. and BARRETT, P. 1993. Mammals of Britainand Europe. Harper Collins, London.

MADDY, D., KEEN, D. H. BRIDGLAND, D. R. and GREEN, C. P.1991. A revised model for the Pleistocene development of theRiver Avon, Warwickshire. Journal of the Geological Society ofLondon, 148, 473–484.


MIALL, A. D. 1996. The Geology of Fluvial Deposits. Springer-Verlag, Berlin.

MILLER, G. H. and MANGERUD, J. 1986. Aminostratigraphy ofEuropean marine interglacial deposits. Quaternary ScienceReviews, 4, 215–278.

MOORE, P. D., WEBB, J. A. and COLLINSON, M. E. 1991. PollenAnalysis, 2nd edn. Blackwell Scientific Publications, Oxford.

MUUS, B. J. and DAHLSTROM, P. 1971. The Freshwater Fishes ofBritain and Europe. Collins, London.

NORTH AMERICAN COMMISSION ON STRATIGRAPHICNOMENCLATURE 1983. North American Stratigraphic Code.American Association of Petroleum Geologists Bulletin, 67,841–875.

OKLAND, J. 1990. Lakes and Snails: Environment and Gastropodain 1,500 Norwegian Lakes, Ponds and Rivers. Oegstgeest, Univer-sal Book Services/Dr. W. Backhuys.

QUIRK, D. G. 1996. ‘Base profile’: a unifying concept in alluvialsequence stratigraphy. IN: Howell, J. A. and Aitken, J. F. (eds),High Resolution Sequence Stratigraphy: Innovations and Appli-cations. Geological Society of London Special Publication, 104,37–50.

READING, H. G. 1986. Sedimentary Environments and Facies, 2ndedn. Blackwell Scientific Publishers, Oxford.

RENDELL, H., WORSLEY, P., GREEN, F. and PARKS, D. 1991.Thermoluminescence dating of the Chelford Interstadial. Earth andPlanetary Science Letters, 103, 182–189.

ROGERSON, R. J., KEEN, D. H., COOPE, G. R., ROBINSON, J. E.,DICKSON, J. H. and DICKSON, C. A. 1992. The fauna, flora andpalaeoenvironmental significance of deposits beneath the lowterrace of the River Great Ouse at Radwell, Bedfordshire. Proceed-ings of the Geologists’ Association, 103, 1–13.

SANDFORD, K. S. 1924. The river gravels of the Oxford district.Quarterly Journal of the Geological Society of London, 80,113–179.

SCOTT, K. 1986. British bone caves: a taphonomic study of Deven-sian faunal assemblages. Unpublished PhD thesis, University ofCambridge.

SIMPSON, I. M. and WEST, R. G. 1958. On the stratigraphy andpalaeobotany of a late-Pleistocene organic deposit at Chelford,Cheshire. New Phytologist, 57, 239–50.

SPARKS, B. W. and WEST, R. G. 1970. Late Pleistocene depositsat Wretton, Norfolk. 1. Ipswichian interglacial deposits. Philo-sophical Transactions of the Royal Society of London, B258, 1–30.

STACE, C. 1991. New Flora of the British Isles. Cambridge UniversityPress, Cambridge.

STUART, A. J. 1982. Pleistocene Vertebrates in the British Isles.Longman, London.

VAIL, P. R., MITCHUM, R. M., Jr., TODD, R. G., WIDMIER, J. M.,THOMPSON, S., III, SANGREE, J. B., BUBB, J. N. and HATLELID,W. G. 1977. Seismic stratigraphy and global changes of sea-level. IN: Payton, C. E. (ed.), Seismic Stratigraphy—Applicationsto Hydrocarbon Exploration. American Association of PetroleumGeologists, Memoir, 26, 49–212.

WEST, R. G., DICKSON, C. A., CATT, J. A., WEIR, A. H. andSPARKS, B. W. 1974. Late Pleistocene deposits at Wretton, Nor-folk. II, Devensian deposits. Philosophical Transactions of theRoyal Society of London, B267, 337–420.

WEST, R. G. 1977. Early and Middle Devensian flora and vegetation.Philosophical Transactions of the Royal Society of London, B280,229–246.

WHEELER, A. 1977. The origin and distribution of the freshwaterfishes of the British Isles. Journal of Biogeography, 4, 1–24.

Amphibian remains from Cassington

A sample of shelly organic silt, from facies association B atface B, was taken on 11 June 1993, and produced thefollowing small herpetofaunal assemblage: common toadBufu bufo, common frog Rana temporaria, Rana sp. (green


frog), Rana sp. (brown frog), indeterminate Anura. There arevery few herpetofaunal records from British sites of post-Ipswichian to pre-Late-glacial age, and any such recordshave an intrinsic value. The presence of an indeterminategreen frog species at Cassington is of particular interest. Thethree species of green frog (R. ridibunda, R. lessonae andR. esculenta) are all notably thermophilous, and offer similarpalaeoclimatic interpretations. These are very aquatic frogs,preferring eutrophic, well-vegetated water-bodies, in andaround which they spend long hours basking. Their northernrange limit reaches 60°N in southern Sweden and 59°N inEstonia, where they inhabit still and running water rich inTypha latifolia, Chara and other aquatic vegetation (Gasc etal., 1997; Gislen and Kauri, 1959). There are numerousintroduced populations in southern England, some of whichmight be native (Snell, 1994). In northwest Europe, thelocation of the 16°C July isotherm approximates closely totheir northern limit, inferring that mean July temperatures atCassington were as high as this.

Green frogs are known from Ipswichian deposits at Shro-pham (Norfolk) (Hallock et al., 1990; Holman andClayden,1990), but not previously from any later temperateepisodes. The Cassington assemblage is compatible witha post-Ipswichian interstadial herpetofauna from Shropham(Holman, 1992), where the grass snake Natrix natrix indi-cates a lush riparian habitat, with summers sufficiently longto allow egg incubation. Both of these faunas are distinctfrom the Middle Devensian interstadial herpetofaunas ofSutton Courtenay (Oxfordshire) and Hyaena Den, WookeyHole (Somerset), where natterjack toad Bufo calamita hasbeen recorded. Bufo calamita is not found at Shropham orCassington, and may be of biostratigraphical value.


References

GASC, J.-P., CABELA, A., CRNOBRJNA-ISAILOVIC, J., DOLMEN,D., GROSSENBACHER, K., HAFFNER, P., LESCURE, J., MARTENS,H., MARTINEZ RICA, J. P., MAURIN, H., OLIVIERA, M. E.,SOFIANIDOU, T. S., VEITH, M. and ZUIDERWIJK, A. (eds) 1997.Atlas of Amphibians and Reptiles in Europe. Societas EuropaeaHerpetologica, and Museum National d’Histoire Naturelle, Paris.

GISLEN, T. and KAURI, H. 1959. Zoogeography of the Swedishamphibians and reptiles with notes on their growth and ecology.Acta Vertebratica, 1(3), 197–397.

HALLOCK, L. A., HOLMAN, J. A. and WARREN, M. E. 1990.Herpetofauna of the Ipswichian Interglacial Bed (Late Pleistocene)of the Itteringham Gravel Pit, Norfolk, England. Journal of Herpet-ology, 24(1), 33–39.

HOLMAN, J. A. 1992. Additional records of Natrix natrix from theBritish Pleistocene, including the first record of a British cold-stage snake. British Herpetological Society Bulletin, 40, 7–8.

HOLMAN, J. A. and CLAYDEN, J. D. 1990. A Late Pleistoceneinterglacial herpetofauna near Shropham, Norfolk. British Herpeto-logical Society Bulletin, 31, 31–35.

SNELL, C. 1994. The Pool Frog—a neglected native? British Wildlife,6 (1), 1–4.

CHRIS P. GLEED-OWENCentre for Quaternary Science

Department of GeographyCoventry University

Priory StreetCoventry CV1 5FB

England

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The Upper Pleistocene deposits at Cassington, near Oxford, England