Great Wilbraham (causewayed enclosure)

Great Wilbraham is a Neolithic causewayed enclosure, an archaeological site near the village of Great Wilbraham, near Cambridge, in England. Causewayed enclosures were built in England from shortly before 3700 BC until at least 3500 BC; they are characterized by the full or partial enclosure of an area with ditches that are interrupted by gaps, or causeways. Their purpose is not known; they may have been settlements, meeting places, or ritual sites. The Great Wilbraham enclosure was first identified from aerial photographs in 1972.

An excavation was begun in 1975 by David L. Clarke, with a planned research programme, but Clarke died in 1976 and the results from the dig remained unpublished for years. The surviving part of the archive of finds and records from Clarke's dig was reanalyzed in the 2000s, and published in 2006.

The site has been protected as a scheduled monument since 1976.

Background
Great Wilbraham is a causewayed enclosure, a form of earthwork that was built in northwestern Europe, including the southern British Isles, in the early Neolithic. Causewayed enclosures are areas that are fully or partially enclosed by ditches interrupted by gaps, or causeways, of unexcavated ground, often with earthworks and palisades in some combination. The use to which these enclosures were put has long been a matter of debate. The causeways are difficult to explain in military terms since they would have provided multiple ways for attackers to pass through the ditches to the inside of the camp, though it was suggested they could have been sally ports for defenders to emerge from and attack a besieging force. Evidence of attacks at some sites provided support for the idea that the enclosures were fortified settlements. They may have been seasonal meeting places, used for trading cattle or other goods such as pottery. There is also evidence that they played a role in funeral rites: material such as food, pottery, and human remains was deliberately deposited in the ditches. The construction of these enclosures took only a short time, which implies significant organization since substantial labour would have been required for clearing the land, preparing trees for use as posts or palisades, and digging the ditches.

Over seventy causewayed enclosures have been identified in the British Isles, and they are one of the most common types of an early Neolithic site in western Europe. About a thousand are known in all. They began to appear at different times in different parts of Europe: dates range from before 4000 BC in northern France, to shortly before 3000 BC in northern Germany, Denmark, and Poland. The enclosures in southern Britain began to appear shortly before 3700 BC, and continued to be built for at least 200 years; in a few cases, they continued to be used as late as 3300 to 3200 BC.

Site
The site is in Cambridgeshire, in the valley of the Little Wilbraham River, east of Cambridge. Two concentric ditches, about 20 m apart, each interrupted by multiple gaps, lie on a flat area on the north-facing side of the river valley, though the river has been diverted and no longer runs on its former path. The site is about 170 m across, and encloses about 2 ha. Most causewayed enclosures are oval, but the two circuits at Great Wilbraham are almost perfectly circular, though many of the ditch sections (between the gaps) are themselves straight lines. Many enclosures were built on valley floors, usually positioned not far above the high water mark of the river, and Great Wilbraham fits this pattern. The site is slightly tilted towards the old river course, with the upper edge of the site at the edge of the higher ground. The enclosure is located on a sandy terrace, in Little Wilbraham Fen, a small fenland area connected to the larger Fens to the north by a stream.

Great Wilbraham was identified by J. K. St. Joseph from cropmarks on an aerial photograph taken in July 1972, and included on a list of 16 possible causewayed enclosures based on observed cropmarks, published in 1975. The site was listed as a scheduled monument in 1976.

A prehistoric henge was tentatively identified in an adjacent field in the 1970s, but has been more recently identified as a disturbed area of gravel.

Clarke, 1975-1976
David L. Clarke was one of the leading figures in New Archaeology, a movement to revise and expand the foundations of the discipline. He had some experience of fieldwork, but had not directed an excavation until 1975, when he started a project to investigate the Great Wilbraham site. John Alexander, the other leader of the project, was a very experienced excavator, and joined Clarke on the project when the plan included using it as a training ground for students. Great Wilbraham had several advantages as a project from Clarke's point of view: it was close to Cambridge; it was expected to be rich in Neolithic material, which was the recent focus of Clarke's teaching work; and it was planned as a way to put into practice some of the theoretical ideas he had propounded over the previous decade. Great Wilbraham was the only known causewayed enclosure to include peat deposits, and Clarke hoped that Neolithic wood might be found as a result, since peat is one of the few environments in which wood can be preserved. According to a later review, the excavation "was intended to be an experiment in what Clarke called total archaeology" (italics in the original). Clarke planned to include interdisciplinary analyses and an evaluation of the surrounding landscape and environment in the project.

A grant from the British Museum funded two weeks of excavation in September 1975; the prospect of finding preserved organic material was the reason for the museum's interest, and the grant came from money allocated for purchasing collections. Clarke and Alexander never published their work, but the grant proposal for the following year records some of the details of the two weeks. A magnetometer survey was done, and fieldwalking to recover surface finds, and a trench 80 m by 2 m was excavated. Finds included animal bone including cattle, sheep, pig, deer and wolf; worked wood; seeds; pottery sherds; and flints. A pollen column was taken. Two more trenches were dug the following year.

Evans et al. 2006
Some of the material from Clarke and Alexander's two seasons of excavation was preserved in an archive, which was stored partly in Cambridge and partly in London. In 2006 the archive was reviewed by a group led by Cambridge archaeologist Christopher Evans, resulting in a paper that presented the results of the original dig, as well as a review of Clarke's ideas and how they were implemented in the field.