"A geophysical survey was undertaken by ASUD in March 2000 on land to the east of the A1(M) at Picktree, Chester-le-Street, where aerial photographic cropmark evidence had indicated a possible Neolithic ritual landscape or Iron age enclosure complex. The survey confirmed the presence of a large ditched enclosure and detected the remains of number of other ditches, some of which correspond to cropmark features. The magnetic effects of modern services and land drains hindered the identification of further features of possible archaeological interest. A later prehistoric date was suggested for the larger ditched enclosure." (The County Durham Sites & Monuments Register, citing "ASUD, Cropmark Complex at Picktree, Chester-le-Street, 2000" as its source)
The map reference given here is accurate to within 1km.