The turf was broken out and cleared by contractors under MOLA supervision. Areas and piling trenches were excavated by machine by the contractors, and monitored by a member of staff from MOLA. Archaeological excavation of features was carried out in accordance with the Written Scheme of Investigation. Trench locations and/or archaeological features were plotted on plans provided by the client using an 'offset methodology' and subsequently tied to the OS grid. Because of the nature of the fieldwork it was not possible to accurately measure/calculate OS OD levels for features recorded, but relative depth levels have been provided where it was possible to measure them - eg 'approximately 3.5m below street level'. The footprint of the new temporary classrooms was stripped to a depth of 0.30m with 25 small trenches of varying size excavated a further 0.45m for the foundation piling. The overall strip and the piling trenches did not encounter natural geology and layers of made ground and build up were encountered across the site. Within the western piling trenches two chalk walls of probable 19th century date were recorded which may potentially be the foundations of a north-south oriented building marked on the 1876 and 1900 plans of the area. The wall had no obvious trench cut and lay above and below layers of made ground. Excavation of new service runs including a manhole and attenuation tank were also observed as part of the watching brief. These reached a maximum depth of 1.20m excavated through made ground. No deposits of archaeological interest were observed in this portion of the watching brief. No deposits pre-dating the mid 19th century were encountered on site.
S Porter (Mon,) studied this question.