(You can find out our progress with this project by following our Site Diary here.)
We first became aware of this feature when Steven Twigg (formally of STAG – South Trafford Archaeology Group) contacted us with an aerial image in 2019. The crop mark shows up quite clearly as a dark green circle and seems to represent a circular ditch around 40m in diameter. Viewing various other aerial images spanning a number of years confirmed the mark to be more than just a temporary agricultural feature.
The size of the circle would suggest something prehistoric and probably older than Iron Age as it is certainly bigger than a roundhouse. The LiDAR image however revealed the site to have a shallow mound in the centre. This would suggest a Bronze Age barrow (similar sized ones can be seen at Normanton Down in Wiltshire). Its central mound and continuous surrounding ditch would suggest a Type 2 Bowl Barrow as classified by Historic England. (ref)
Other features are also noted on the LiDAR image. About 230m to the south on the other side of the road leading to Gorses Farm, another circular mound can be seen. This is quite visible on the ground, but its size would suggest that it’s a natural feature probably a product of glacial activity. A linear feature runs for 370m (or perhaps more) diagonally to the northwest just 50m north of the ring ditch feature. This feature seems to relate to an old field boundary which is shown on early maps.
The site lies in an open field which gently slopes towards the east. From the site, there are extensive views over the fields towards Bolton to the east (its football stadium can be seen in the distance lying at the foot of Winter Hill). In the middle distance, Borsdane Brook runs from north forming the boundary of the Wigan Metro Borough. On our first site visit, we were able to talk to the landowner who showed great interest and allowed us to wander over the field. We attempted drone imaging, but this failed to detect anything. However, the shallow mound was just about discernible on the ground.
In May 2021 Chris Drabble carried out a comprehensive aerial drone survey. This revealed a dry central circular area 23m diameter rising to a height of 1.4m and surrounded by a further damper area 6.5m wide. This seemed to confirm that the feature is man-made (Drabble, 2021).
In the Autumn of 2021, we carried out a resistivity survey of the site with very encouraging results as reported in our October Newsletter (No.246). Our two scans covered an area 50m x 46m and revealed the existence of below-ground archaeology in the form of a huge circular feature with central targets and possible outer bank in the southwest corner.
The next step would be to carry out some form of excavation but first we needed a Project Plan to know how this will be undertaken by setting out our aims and objectives and formulating a methodology. It is envisaged that excavations would be carried out in phases, the first phase being an exploratory trial trench (no more than 2m x 11m) across a section of the circular feature. The suggested position would cover a rare area where both crop marks from Google Earth and ESRI more or less coincide with the result from our resistivity survey.
You can find out our progress with this project by following our Site Diary here.