Robert G. Scaife

The Upper Pleistocene deposits at Cassington, near Oxford, England

For much of the Middle and all of the Upper Pleistocene the Upper Thames valley has remained outside the limit of ice advance. The main agents of landform evolution have been the River Thames and its tributaries, which have cut down episodically and in so doing have abandoned a series of river terraces. This study reports the findings of an investigation into 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 deposits indicates 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 a marked change from temperate at the base, to colder conditions towards the top, indicating a close association between deteriorating climate and changing fluvial depositional style. Amino acid and luminescence geochronology from the basal fine-grained lithofacies suggest correlation with Oxygen isotope Stage 5 and hence it is argued that the major environmental change recorded at the site relates to the Oxygen-Isotope Stage 5-4 transition. Deposition of much of the overlying gravel sequence probably occurred during Oxygen isotope Stage 4, suggesting that the latter half of the Devensian may be less significant, in terms of fluvial landscape evolution in the Upper Thames valley, than was believed previously

Environmental and sea-level changes in London from 10 500 BP to the present: a case study from Silvertown

Results of stratigraphic and palaeoecological studies carried out on deposits at Silvertown in east London are discussed in relation to current models of Late glacial and Holocene alterations to river form, relative sea-level change, vegetation development and archaeology in the lower Thames. The data indicate that the braided bedform typical of British cold stage rivers evolved into a lower energy meandering form around 10 500 BP, a process that caused channel cut-off. The fill of one of these contained organic sediments and in-washed sands dating from 10 500-9300 BP in which there was palynological evidence for the replacement of Late Devensian tundra by early Holocene pine forest. Biostratigraphic evidence for the period 9000-5500 BP was limited owing to the absence of organic sediments and, instead, deposition was of in-channel sands. Peat formation began at c. 5500 bp , and these organic sequences contain evidence of the elm decline at 5010±70 BP and the lime decline at 3070±60 BP. The latter event was accompanied by forest clearance for Bronze Age agriculture and a consequent alteration to both the marsh and dry ground flora. Around 2500 bp the peats were submerged beneath estuarine muds as a result of further sea-level rise. A series of age/altitude points relating to Holocene sea-levels were constructed from the site data and were found to fit relatively well with current ideas of sea-level change in the post-glacial period. The results from Silvertown reflect data from shorter sequences in the London area, combining evidence of the Late glacial to early Holocene transition, with information on river development, changes in sea-level tendency and human-induced vegetation change.

An Early Mesolithic Seasonal Hunting Site in the Kennet Valley, Southern England

A small-scale excavation, undertaken in advance of building works at Faraday Road, Newbury, Berkshire, encountered an apparently intact Early Mesolithic layer containing abundant worked flint directly associated with animal bones. The site lay on the floodplain of the River Kennet in an area already well-known for Mesolithic remains and certainly represents an extension of the site found at nearby Greenham Dairy Farm in 1963. The flint assemblage was dominated by obliquely-blunted microlithic forms accompanied by a restricted range of other items. The animal bones were, unusually, dominated by wild pig with clear evidence of both primary butchery and food waste. Spatial analysis of the bone and flint assemblages indicated discrete activity areas, possibly associated with hearths. Both pollen and molluscan data were recovered which, together with the results of soil micromorphological examination, confirmed an Early Holocene date for the formation of the Mesolithic layer. Radiocarbon dates place the site in the late 10th–early 9th millennium BP. The paper re-examines the nature of known Early Mesolithic activity in this part of the Kennet valley, with particular reference to the specific environmental conditions that seem to have prevailed. It is concluded that the Faraday Road site represents one part of a continuum of Early Mesolithic occupation that stretches along a considerable length of the floodplain, with each focus of activity witnessing repeated, but intermittent, occupation spanning a period of more than a millennium.

Archaeological and Palaeo-environmental Investigations of the Upper Allen Valley, Cranborne Chase, Dorset (1998-2000): a New Model of Earlier Holocene Landscape Development

A combination of on- and off-site palaeo-environmental and archaeological investigations of the upper Allen valley of Dorset conducted in 1998–2000 has begun to reveal a different model of landscape development than those previously put forward. A combination of off-site geoarchaeological and aerial photographic survey and palynological analyses of two relict palaeochannel systems, and sample investigations of four Bronze Age round barrows and a Neolithic enclosure, have been combined with inter-regional summaries of the archaeological and molluscan records to re-examine the prehistoric landscape dynamics in the study area. Preliminary results suggest that woodland development in the earlier Holocene appears to have been more patchy than the presumed model of full climax deciduous woodland. With open areas still present in the Mesolithic, the area witnessed its first exploitation of the chalk downs, thus slowing and altering soil development of the downlands. Consequently, many areas perhaps never developed thick, well structured, clay-enriched soils (or argillic brown earths), but rather thin brown earths. By the later Neolithic these under-developed soils had become thin rendzinas, largely as a consequence of human exploitation. The presence of thinner and less well-developed soils over large areas of downland removes the necessity for envisaging extensive soil erosion and thick aggraded deposits in the valley bottom in later prehistory. The investigations have suggested that, if there were major changes in vegetation and soil complexes, these had already occurred by the Neolithic rather than in the Bronze Age as suggested by previous researchers, and the area has remained relatively stable since.

A Neolithic trackway within peat deposits at Silvertown, London

Excavations at Fort Street, Silvertown, London revealed a short length of a prehistoric trackway constructed within the floodplain of the Thames. Two pollen profiles were obtained through peat together with four radiocarbon dates; two from the trackway itself, one from near the bottom and one from near the top of the peat. These dates indicate that the trackway was constructed in the Early Neolithic and that peat formation took place in the Neolithic and Bronze Ages. The trackway is of considerable importance in that it represents the earliest known structure of this kind yet discovered in the London area.

Sedimentology of a tidal point-bar within the fluvial–tidal transition: River Severn estuary, UK

Abstract Inclined heterolithic stratification (IHS) forms the upper parts of a vegetated point-bar that forms the channel bank in the fluvial–tidal transition toward the head of the Severn Estuary. Continuing accretion of IHS occurs at the level of mean high water spring tides. The IHS overlies bar sands. The channel bank is convex upward with a tidal current-eroded scarp near the level of mean high water neap tides. At the foot of the scarp is a sandy bar reworked by tidal currents and weakly bioturbated by all but the lowest neap tides. The sandy bar is within the tidal channel and sections exhibit faint horizontal lamination with occasional ripple cross-lamination, mud flasers, reactivation surfaces, and convolutions. Convolutions are ascribed to pressure fluctuations due to tidal bores. In contrast, the IHS of the point-bar consists of distinctive thin laminations of sand, silt, and clay deposited by the higher spring tides. The channel bank top is inundated by slow currents, with little opportunity for reworking, which explains the preservation of distinctive IHS. The influence of high river discharge is not evident in the depositional signature, probably due to the intense mixing of high concentration estuarine suspended sediment in all weather and seasonal conditions.

A Final Upper Palaeolithic Site at La Sagesse Convent, Romsey, Hampshire

Excavations at La Sagesse Convent, Romsey, uncovered a Final Upper Palaeolithic flint assemblage representing an open-air, short-term camp. The site is in the Test Valley on a low gravel terrace at the edge of the river system. Two scatters were found. Although not in situ, little lateral movement is indicated for at least one of these scatters from which several core reduction sequences could be determined through a programme of refitting. The other scatter appears to have suffered more post-depositional disturbance. One scatter appears to have functioned as a knapping station, while the other may have been an area of tool production. Chronological, technological, and cultural affinities are discussed and it is concluded that the flint assemblage belongs with the Final Upper Palaeolithic Hengistbury-type industries, probably dating to the second part of the Windermere interstadial (c. 12,500-11,000 cal BC; 12,000-11,000 BP).

Making the most of it : Late prehistoric pastoralism in the Avon Levels, Severn Estuary

A combination of archaeological and palaeo-environmental field work in the Avon Levels, western England, has enabled a much better understanding to be reached of the complex Holocene sedimentation in this part of the Severn Estuary, and of the close relationship between the upper part of that sequence and opportunities for exploitation of this wetland region during the later prehistoric and Romano-British periods. This paper explores that relationship, focusing in particular on two Iron Age to Romano-British sites. Both sites, at Hallen and Northwick, appear to have been short-lived and only seasonally occupied in order to exploit rich grazing but this occupation took place at different times and within rather different patterns of land-use. The paper concludes with an outline model for the human use of the Avon Levels from the Neolithic to Romano-British periods.