Oriel College, Oxford Kitchen Project Geophysical Survey, Archaeological Borehole and Watching Brief Report

In August 2017 Oxford Archaeology (OA) coordinated a geophysical survey (GPR and ERT) of all three college quadrangles, together with a E-W aligned borehole transect, located in the central quadrangle at Oriel College, Oxford. In January 2018 OA conducted a Watching Brief on two small geotechnical pits, TP 3 and TP 4 located to examine the foundations of the structures on the south and east sides of the development area, the boundary wall to Magpie Lane and the north wall of the Chapel respectively. The work was designed to further inform the Planning Authority in regard to the archaeological potential, specifically any evidence pertaining to putative Late Saxon defences for a primary burh, on the site of proposals to create a new basemented kitchen and other facilities at the college.

The GPR did not penetrate to depths below c 1.0m B.G.L and therefore did not give any useful information about the archaeological remains within all three quads. The ERT technique was hampered by interference in the northern quad, but more successful within the central and southern quads, and an eastwards dipping horizon to the natural gravel topography was identified in the southern quad.

The borehole transect in the central quad revealed a complex, sequence of occupation deposits dating to the medieval period. Samples from occupation deposits directly overlying the gravel in two boreholes, produced dates spanning the 12th to 13th centuries at 1165-1265 cal AD and 1225-1300 cal AD. The medieval sequences measured between 1 – 2.2m thick and were highly variable in composition and thickness. It is highly likely that some of these deposits represent the fills of intercutting archaeological features (such as pits, and possibly cellars for buildings) resulting in the truncation of the natural loess and gravel deposits in this area, multiple thin layers may equate to internal floor surfaces, and occupation deposits. No large N-S feature was logged, no deposits, such as limestone or gravel surfaces that may be interpreted as possible roadways and no significant redeposited brickearth or gravel indicating an earthen bank were identified.
Considering this evidence along with previous archaeological work both at Oriel and neighbouring colleges, a c. 10 – 13m wide N – S ditch can be suggested to have run directly below the east ranges of the central and southern quads at Oriel. A parallel extra-mural road would have probably lain beyond the ditch to the east. The suggested alignment of ditch and road does not follow Magpie Lane, however, it does interestingly follow the alignment of the eastern ranges of the central and southern quads of Oriel College, Grove Lane and the eastern college ranges at Corpus Christi (perhaps later echoes of earlier boundaries/land divisions).
An intramural N-S road has been suggested running parallel with the inside line of a probably bank inside the line of the ditch, no evidence of an earthen bank, or a road structure was found within the borehole transect, however evidence from Corpus Christie confirmed a probable Late Saxon road surface in this location, and perhaps this intramural road is similar to the current alignment of Oriel Square and Oriel Street.