Experts say their excavations will reveal more about the history of the henge fully uncovered for the first time in Raunds.
A team of archaeologists from Oxford Archaeology East have been working on behalf of Roxhill at the Warth Park development.
As part of the mitigation strategy for the development, overseen by Liz Mordue, archaeological advisor for Northamptonshire County Council, and advised by Matthew Nicholas the Historic England science advisor for the East Midlands, excavation of the monument known as Cotton Henge is currently under way.
Cotton Henge was first identified by aerial photography back in the 1970s and recorded on the Northamptonshire Historic Environment Record.
It has previously been archaeologically investigated on two other occasions.
Cotton Henge is likely to date from the Late Neolithic period (c.3000-2500BC) and forms part of a larger group of ceremonial features which were located on the floodplain around the River Nene toward Irthlingborough and Stanwick, which were excavated as part of the Raunds Area Project.
The current archaeological fieldwork is the first time the henge has been uncovered in full.
The purpose of the excavation is to try and confirm its date, function and context within the wider landscape.
While this monument is commonly known as Cotton Henge, it’s interpretation as a henge has always been a tentative one.
A ‘classic’ henge comprises a ditch with an external bank with one or more entranceways, but here the ditch appeared unbroken when the site was first investigated.
Hand excavation of the henge by the present archaeological team has identified a small possible closed off entranceway on the southern side of the outer ditch.
Cotton Henge is formed purely of two ditches which would originally have had associated external banks, it never contained any standing stones.
Liz Mordue, archaeological advisor to Northamptonshire County Council, who is monitoring the archaeological works on the site, said: “The NCC Archaeological Advice Service has been involved with the Warth Park site since 2011.
“The current excavation work is being undertaken in advance of construction as part of the planning process and was preceded by an evaluation using geophysical survey and trial trenching.
“This allowed us to put together a detailed mitigation programme at an early stage of the development.
“The excavation has been progressing as intended and is providing a great deal of information about the site and its surrounding landscape.
“All work in Northamptonshire is undertaken against the background of the East Midlands Research Framework which enables us to focus our work on detailed research objectives and ensures that we achieve meaningful results, not only for the archaeological profession but also for the communities where the work takes place.”
Matthew Nicholas, Historic England’s science advisor for the East Midlands, said: “The monument known as ‘Cotton Henge’ is not a new discovery, but it is exciting to see it fully uncovered for the first time.
“The monument was first discovered over 30 years ago and was studied carefully in the 1980s and ‘90s but there were still some unanswered questions about its function.
“We have been advising the NCC archaeological advisor to ensure that the latest scientific techniques are used so that we can gain a greater understanding on how the henge was use, and how the landscape around it developed.”
The excavations on site are planned to continue for a few more weeks, following which the archaeological team will be writing up the results of the excavations.
A series of talks and lectures are planned to local history societies regarding the results of the excavations in the near future.
In the longer term, a full report detailing the findings will be issued to the NCC archaeological advisor for approval.
Once the report is approved it will be put online and made accessible to the public.