NEOLITHIC AND LATER PREHISTORIC LANDSCAPE OF THE AVON VALLEY 229 
to the river is a distinct levee (Figure 6, borehole 10) 
built up from dredging and dumping along the 
banks. This comprised up to 1m of silts with 
derived ash, and modern (glazed) pottery was 
recovered in the silts beneath the make-up. 
SAMPLING AND POLLEN 
ANALYSIS (core 6) 
Coring was undertaken using a 30mm diameter 
gouge corer with a lm chamber because of the 
relative dryness and stiffness of the sediments. 
Sampling was carried out at 20mm intervals in the 
field. Samples of 1ml were prepared using standard 
pollen extraction techniques (Moore et al. 1991). A 
minimum of 300 pollen grains plus spores was 
counted at each level, and where pollen was more 
abundant a greater sum was obtained. Full details 
are given in archive. 
The results are presented in standard form as a 
summary diagram only (Figure 7) with pollen 
represented as a percentage of total dry land taxa 
and spores as a percentage of total pollen plus 
spores. Pollen of marsh and aquatic taxa are 
calculated as a percentage of total dry land pollen 
plus determinable wetland taxa. Nomenclature 
2) 
o 
io 
s 
o 
= 
follows that of Stace (1991) for plants and Moore et 
al. (1991). 
Forty-one levels were analysed at 20mm 
intervals from the base at 1.60m to 0.92m and at 
40mm intervals from 0.92m to 0.68m. A number of 
significant changes can be seen in the pollen 
stratigraphy which have enabled four principal 
pollen assemblage zones to be assigned 
(Durrington: 1-4, Figure 7). The most significant 
pollen assemblages (Durrington: 1) relate to late 
Devensian and early Flandrian conditions and 
there is little evidence of human interference in this 
natural sequence, or evidence of relevant 
archaeological activity, so this data is only 
summarised here. 
VEGETATION HISTORY 
The depositional environment of river floodplains 
present problems not usually encountered in the 
peat forming environments of larger fens and bogs. 
Taphonomic questions of sediment/pollen sources 
and river erosive and depositional processes must 
be considered in addition to interpretations about 
the local/autochthonous and region/pollen sources 
(cf. Burrin and Scaife 1984; Scaife and Burrin 1992; 
Hunt 1987; Moore et al. 1991). 
KEY 
my Topsoil = Alluvial/grey silt 
YA Peat Gravel 
Calcareous marl Greensand 
EE Buff marl % Roman pottery 
8640+ 200BP 
1 
100 metres 
Fig. 6 Schematic profile through the auger transect across the Avon valley 
