NHER 62655 (Monument record) - Post-medieval features and deposits

May 2011-March 2012. Watching Brief.
Monitoring of groundworks associated with construction of a new technical block. A variety of excavations were monitored and pile arising were also examined.
The pile arisings consisted primarily of Kimmeridge Clay with some peat and rare deposits of clean yellow sand also noted. These observations are consistent with the results of an earlier geotechnical survey that recorded a sequence consisting of Kimmeridge Clay overlain by glacial sands, a thick layer of Nordelph peat and finally a layer of dark grey organic alluvial (the later forming part of what is termed the Terrington Beds by the British Geological Survey). Finds recovered from the pile arisings included a fragment of medieval brick and two post-medieval pottery sherds.
The subsequent groundworks all exposed a broadly similar deposit sequence consisting of a pale grey alluvial clay overlain by a black silt that produced fragments of post-medieval pottery and ceramic building material. This was in turn overlain by another black silt deposit that contained flint and 20th-century demolition rubble. Deeper excavations for a rain water tank exposed the black peat that had previously been shown to lie beneath the alluvial clays. This layer was found to be approximately 0.8m deep and contained frequent reed and wood fragments.
Two features were identified beneath the dark soils, the first of which was a substantial, steep-sided pit that produced a significant amount both of clay pipe and pottery, the bulk of which dates to the 18th century. The second feature appeared to be a north-to-south aligned ditch and had a black silty peat fill that also produced pottery and clay tobacco pipe of probable 18th-century date.
It is unclear whether the overlying dark soils represented a phase of arable agriculture or the deliberate deposition of material in order to raise the ground level. The earliest available maps of this area mark it simply as ‘Marshes’ but by the late 19th century the site was part of a large orchard within an area known as Highgate.
See report (S1) for further details.
P. Watkins (HES), 13 April 2018.