Cock Marsh

The University of Reading are leading a gradiometer geophysics survey of a Bronze Age/Early Medieval site at a field containing around 20 barrows near the Thames at Cock Marsh at the end of April, and are looking for volunteers who can assist. This area is a scheduled monument, and will be very interesting to visit, as well as to try and better understand the complex archaeology of the site.

The round barrow site at Cock Marsh is sighted on the meander of the River Thames, 1km to the west of Bourne End. The known monument contains four bowl barrows, all of which survive as cropmarks (Historic England 1991). The Cock Marsh cemetery is particularly important as it survives well, and despite partial excavation (1874-1877) has considerable archaeological potential .  

Location of proposed survey area containing scheduled monument no. 1012812

By undertaking this survey the Berkshire Archaeological Society will be supporting this University of Reading led project, and collaborating with volunteers from other archaeological societies across the Middle Thames area with whom the University of Reading is be engaged. The volunteers participating in this project will include members of the local community who have no prior experience of geophysics or archaeological fieldwork, bit this outreach is part of the  University of Reading’s wider programme of engagement with Cookham residents of which this project is part.

The survey will be managed and run by The University of Reading, in partnership with the National Trust, who own the land, and the local societies of Berkshire Archaeological Society, Maidenhead Archaeology and Marlow Archaeology Group.

Background 

Cock Marsh is an area of National Trust-managed common land adjacent to the River Thames in which is located a well-known barrow cemetery, about 2 km north-west of Cookham village. Research during and after the Archaeology in East Berkshire project (Humphreys 2019) conducted by the University of Reading in 2018/9, consisting of inspection of Air Photos from Google Earth and Environment Agency LiDAR, suggested that this cemetery could occupy a larger area, i.e., more barrows that have not been recorded through being too ephemeral for visibility at ground level. 

The known barrows number four definitely agreed on, which were the subject of an excavation by antiquarian Alfred Heneage Cocks between 1874 and 1877. Also, Ordnance Survey mapping in the past has shown a fifth to the south of the main group. More recently, another barrow to the east of the main group (i.e., not the one on the OS mapping) has been recorded on the HER, derived purely from an air photo. 

The barrows that Cocks excavated had an interesting mix of contents, including human and animal remains, and features that suggested Bronze Age origin, but with one barrow containing a clearly early medieval burial with grave goods of that period. Whether that barrow was added in its entirety in the early medieval, or whether the burial was an insertion into an earlier barrow, is not known. 

Current Project 

The location of the early medieval monastic settlement (“Cookham Abbey”) at the Church Paddock, Cookham has led to renewed interest in other archaeology in the neighbourhood. It is now well established (Semple 2013 and others) that early medieval settlements, not least Christian religious structures, were often sited with clear reference to visible monuments from earlier periods. One interpretation of this phenomenon is that incoming Germanic settlers were claiming the land as their own by adopting the people buried there as their own ancestors. In the conversion period, this could have been important in overcoming potential resistance from kings and others who would not have wished their ancestors excluded from salvation. 

The question whether the Cock Marsh barrows would have been visible from Cookham Abbey, and possibly therefore part of a processional route, is one that has led to a collaborative project to re-survey Cock Marsh to see if the extent of the barrow field can be better defined and its relationship to Cookham Abbey, if any, established. The leading partners in the project are the University of Reading (UoR) and the National Trust. The gradiometry survey was designed by Dr Rob Fry, of the UoR. Keith Abbott worked with Rob to complete the programme design with a view to bringing in volunteer resource, which was organised by the author. The final project plan settled on two teams to work in week 1 – Rob Fry leading one team to include students and volunteers; Keith Abbott and the author leading the other team of volunteers only. It was decided that in this first week, two gradiometers owned by the UoR would be used to ensure consistency. In the second, volunteer-only week, BAS came into its own by providing its own gradiometer and Keith’s supervision of the volunteer teams over four days. 

Fig 1 – Preliminary gradiometry result (part of site) North is at the top. 
(Image courtesy of the University of Reading) 

The image presented in fig. 1 is the result of high-resolution (0.5m) gradiometry in the vicinity of the known barrow group. A number of interesting results are apparent. 

First, though, note that the linear anomaly in the top right area is a known buried high-tension electricity cable. 

The most well-known barrow that stands to a height of nearly 2m is apparent in the centre of the image. The HER records it as a bowl barrow with no visible ditch. The Historic England Scheduled Monument particulars record one buried ditch. https://historicengland.org.uk/listing/the-list/list-entry/1012812?section=official-list-entry 

Our survey shows not only one certain ditch but very probably also a second. 

To the left (west) of this first barrow, a second barrow remains visible at about a meter in height but is truncated to the west by the boundary fence with a farmer’s arable field. This is the site of the early medieval inhumation. In the farmer’s field, you can see LiDAR markup where there are no visible remains of the barrow; this clearly matches with the gradiometry result. 

In the very top left-hand corner, another LiDAR feature is shown. The gradiometry result is quite busy at this point, so there is some prospect that this is another archaeological feature, but on the Cock Marsh side of the boundary it lies tantalisingly beyond the reach of our survey. 

A little to the south south-west of the largest central barrow is an anomaly that appears to be sub-circular, not an obvious ring-ditch, but is the location of the fourth known barrow, barely visible on the surface. According to Cocks, this barrow contained horse remains and 17th century bottle fragments. 

To the west of this barrow is a linear negative anomaly that might be worthy of further investigation. 

Saving the best till last, further toward the bottom right of the image is an obvious ring-ditch, but it is located where there is no feature recorded on the HER or the HE listing particulars. This clearly requires further investigation. 

Conclusion 

It will be of great service to the National Trust and to Historic England to have created this new geophysical perspective on the site. It remains possible that the planned further geophysical survey of the wider Cock Marsh may reveal more that is of interest. However, it should be noted that to the east of the scheduled area Cock Marsh is largely covered by a layer of alluvium which will have buried the prehistoric ground surface, so detecting anything more is problematic. 

The greatest gain from this project, however, has been outreach to the local community. Altogether 80 volunteers, mainly local to Cookham and Maidenhead expressed interest in taking part. Fifty-eight of these, including eight BAS members, actually worked in the nine days of the project and many want to repeat the experience. 

For more information contact Paul Seddon at paul(at)c21networks.co.uk

For security we are not publishing email addresses as direct links. Please re-type substituting the @ symbol for (at)

Exploring the archaeology, history and heritage of Berkshire