EDO4157 - St John Ambulance Hall, North Square, Dorchester, Evaluation Trench 4

Terrain Archaeology carried out an archaeological evaluation of the former St John Ambulance Hall, North Square, Dorchester, during February 2000. Four hand-dug test pits (Trenches 1-4) were excavated (1) (2). Trench 4 measured 1m x 1m and was excavated on the eastern side of the site, 5.5m north of Trench 3, to a depth of 1.2m. Natural deposits were not reached. 0.1m topsoil lay above 0.45m of 20th century made ground associated with the construction of the St John Ambulance Hall. This lay above 19th century soil and rubble layers associated with landscaping following the construction of houses on Orchard Street. The trench was backfilled and later re-excavated under archaeological supervision for an engineer's test pit on March 15th 2000. The excavation went 0.3m deeper than before and eventually a depth of 2m was reached in a small sonage in the SE quadrant. The 19th century deposits were not bottomed and a probe established that chalk bedrock lay at a depth of 3.4m below the surface (3).