St John's Triangle, Cambridge. Archaeological Watching Brief
During August and September 2005, staff from the Cambridge Archaeological Unit carried out monitoring on a series of 27 hand-excavated test pits situated within the area of St John’s Triangle, Cambridge. This also provided an opportunity to assess the character, extent and preservation of archaeological deposits as exposed within the test pit sections, and to retrieve dating evidence such as ceramics. Being located within the heart of Medieval Cambridge, a significant depth of archaeology was expected based on the results of other excavations within the immediate vicinity. Within areas of open space, such as the back yards, up to three metres of stratigraphy was noted from the test pits and additional borehole data. Areas that had been cellared would normally be assumed to have little if any surviving archaeology. However, this study demonstrates the survival of horizontal stratigraphy and the fills of cut features at this low level up to one metre in depth. It is also clear that 18th/19th century activity outside of the cellared areas has had a limited detrimental effect on the earlier strata. Traces of a compact gravel surface, provisionally dated to the Roman period, were exposed along the Bridge Street frontage below the level of the cellar floors. Saxo-Norman pottery was also recovered from several test pits in the southern half of the development area. Evidence for the truncation of the underlying natural gravels was also evident and it is possible that the presence of a large feature such as St John’s ditch, believed to run across the southern half of the area, may be a factor in explaining the differentiation in natural height between neighbouring test pits.