Phase 500 Riverside Way Uxbridge

Between July and September 2014 Oxford Archaeology completed an
archaeological field evaluation at Riverside Way, Uxbridge, in the London Borough
of Hillingdon. The fieldwork comprised the excavation of 76 test pits arranged on a
10m grid designed to assess the potential for the presence of lithic artefact scatters.
The test pits were excavated through a Holocene sediment sequence to the surface
of the underlying Pleistocene sand and gravel. No features or artefact
concentrations of archaeological significance were encountered. Three pieces of
prehistoric worked flint were recovered along with a small assemblage of 19th-20th
century pottery, glass and metal.
The site is located on the floodplain of the River Colne and a relatively shallow,
sequence of waterlogged Holocene alluvial and peat deposits lay preserved
beneath c 0.5-1.0m of brick rubble made ground capped by a concrete slab. At the
base of the sequence a possible buried land surface was recorded over Pleistocene
sand and gravel. Geoarchaeological and palaeoenvironmental sampling was
undertaken in several test pits and two representative sequences were chosen for
laboratory assessment and radiocarbon dating. Four radiocarbon dates from two
test pits confirmed much of the lower part of the sequence was deposited during the
early Holocene at c 9150-7980 cal. BC. Pollen was shown to be well preserved and
correlations can be made with other sites in the region. However, macroscopic plant
remains were poorly preserved and molluscs were generally only well-preserved in
association with an eroded calcareous tufa deposit present within the north-western
part of the site.
The earliest Holocene deposits and paleoenvironmental remains demonstrate the
primary development of a soil horizon within a landscape represented by the pollen
of grass, sedge and pine with rare hazel and willow. These deposits also produced
fungal spores that typically established in association with tundra vegetation
following glacial retreat. This was followed by wetter local conditions and the
development of the peat horizon recording an increase in the broad-leaved tree
species in the surrounding environment otherwise dominated by pine. The organic
clay deposits overlying the peat represent wetter and regularly inundated site
conditions. Again, the surrounding habitat appears to be dominated by pine pollen
but with increasing amounts of broad-leaved species and herbs present. The wet
site conditions are reflected by the presence of a variety of aquatic species. A
radiocarbon date of c 8700-8460 cal. BC was obtained at this level. Above this, tree
species declined being replaced by sedges, grasses and aquatic plants.
The sequence of deposits, date of deposition and palaeoenvironmental results are
similar, though perhaps less well preserved, than other sequences analysed in
greater detail in the surrounding area. The Riverside Way sequences frequently
appeared conflated and affected by post-depositional processes along with areas of
modern disturbance associated with the previous development at the site. Similarly,
deposits recorded during an evaluation immediately to the north of the site in 2005
produced comparable sequences with no direct evidence present for prehistoric
activity other than a single worked flint. Contrasts to this area can be drawn with
sites such as Three Ways Wharf, the Sanderson site and William King Flour Mill c
1km to the north and sites around Denham, which have produced well-preserved
palaeoenvironmental, lithic and faunal assemblages providing substantial evidence
of Mesolithic activity within the valley