Prior to the need for archaeological monitoring, concrete piling occurred across the development site. Footings trenches were then excavated intermittently using a 360 excavator with a bladed bucket. The footings trenches were excavated to a depth of 1.2m across the development area using a dumpy laser level to ascertain depth. After an area of approximately 5m in length by 1.8m in width had been excavated under close monitoring by the attending archaeologist, the trench would then be prepared for shuttering and steel cages tied into the existing concrete piles ahead of the concrete pour. This intermittent process was followed until the entire scope of trenching had been completed. The service trenching in the north-eastern corner of site, immediately adjacent to the road, was continuously monitored but revealed no archaeological evidence. The use of GPS recording was unavailable for the final five meters of the trench, as an incident occurred on site which caused damage to the base unit. The road strip that took place in the northern portion of site, that ran perpendicular to Abingdon Road and to the western boundary of site was also monitored; no archaeology was encountered. Additionally, a service trench extending the full length of the road strip and a manhole, placed approximately 3 metres to the west of the Abingdon Road site boundary, were excavated. Evidence of, or associated with, the Grandpont causeway was not seen within the development area, neither was evidence of any other medieval roadside activity. The north-east to south-west aligned ditch 05 yielded dating evidence from the Post-Medieval period. Comparison with the Cumnor & South Hinksey Enclosure Map of 1814 demonstrates that this was likely a former field boundary. If any remnants of the Grandpont causeway are still extant in the vicinity of the development site it is likely they are directly overlain by the Abingdon Road.
Orlando et al. (Wed,) studied this question.