Knollbury
Knollbury is a scheduled neolithic enclosure to the north west of Chadlington in Oxfordshire. Believed to be defensive in nature the enclosure is rectangular (100 metres by 150 metres) formed by a two to four metre high and ten metre wide earth banks. The two gaps in the earth banks at the eastern corners are believed to be of a later date.
Coordinates: 51°54′17″N 1°32′29″W / 51.9047°N 1.5415°W
...
Wikipedia