Westgate Centre, Oxford

Between September 2007 and February 2008, Oxford Archaeology carried out an archaeological evaluation at The Westgate Centre, Oxford (centered on SP 5108 0594). The work was carried out on behalf of Sir Robert McAlpine Ltd, who were commissioned by The Westgate Partnership. The Westgate Partnership is a joint venture between Capital Shopping Centres plc and Coal Pension Properties Ltd and is proposing the redevelopment of the existing Westgate Centre and associated car parks (both multi-storey and surface level). The current phase of evaluation (Phase 2) followed on from the Phase 1 evaluation carried out by OA in 2006 (OA, 2006).
The Phase 1 evaluation comprised 16 trenches, the majority of which were excavated on the floodplain and the deposits encountered reflected this, with the evidence from these trenches being predominantly palaeo-environmental in nature. Trenches to the north within the multi-storey car park did, however, identify architectural and other remains associated with the medieval Greyfriars.
Phase 2 comprised a further 19 trenches, 7 within the multi-storey car park and 5 in the surface car parks, with a further 7 in areas adjacent to the car parks which will be affected by the proposed development. These formed part of the required archaeological mitigation but also provided further evaluation of the surviving archaeological resource, in particular the development of the Trill Mill Stream and the extent and character of the conventual buildings of the Greyfriars Priory.
The evaluation largely confirmed the results of the first phase, although the additional data recovered have allowed the site specific model for the hydrological and sedimentary development of the floodplain to be refined. This model still correlates broadly with the sequence postulated from previous excavations to the south of the medieval walled town, and elsewhere on the floodplain of the Upper Thames.
Evidence for an elevated area of gravel to the south-east of the site suggested that this area is on the periphery of an 'island' of higher ground, although the nature and elevation of the deposits encountered implied that this was marginal land, and unlikely to be the focus of settlement similar to that previously excavated at Whitehouse Road.
The evaluation provided confirmation of the Trill Mill Stream crossing the centre of the site, and further evidence for the origin, development and orientation of the channel was recovered. In addition, the results from a number of trenches suggested the existence of a complex system of intercutting side channels (some timber lined) to the south of the stream. One of these comprised a set of substantial timber beams which were encountered in previous investigations, and have been interpreted as part of a mill race. Demolition material overlying these timbers was suggestive of an adjacent mill associated with the Greyfriars priory to the north-east.
There was also some evidence for managed water courses between the Trill Mill Stream and the Thames, which may have been contemporary with the Greyfriars' ownership of this area of the site, referred to in documentary sources as Boteham Island.
Additional evidence for 13th-14th century land reclamation extending southwards from the second terrace was also revealed. Further robbed and partially robbed walls associated with the Priory and its subsequent demolition were seen to cut this deposit(s), as was a possible western boundary to the Greyfriars complex, comprising a north-south aligned ditch, later superseded by a limestone wall. This latter appears to correspond to the boundary between the Priory complex and the area known as Paradise to the west.
The remaining recorded deposits appeared to relate to the use of the area as gardens/pasture, and subsequently the construction of Victorian terraced housing and the demolition of same in the late 1960s.