Crossing the Cam
The varied topography of Cambridgeshire has resulted in a wide array of types of historic land use; the evidence for the underlying pattern of prehistoric and Roman occupation of the area is largely hidden, but plays a formative role in the landscape’s history.
Historic England’s South West Cambridgeshire National Archaeological Identification Survey (NAIS) is exploring the relationships between these layers in the landscape.
The first stage of the project, which has recently been completed, used aerial photographs and digital elevation models such as lidar to map and record archaeological sites and landscapes dating from the Neolithic through to the Second World War. The results will directly inform planning decisions, as well as providing a framework for future survey and research.
The project area stretches from the historic fen edge at Fenstanton to the Hertfordshire chalk downs south of Royston. Taking in most of the Bourn Valley and a large section of the River Cam (or Rhee), it allows a unique insight into the relationship between the natural environment and the archaeological monuments within it.
Nowhere is this more evident than with Late Iron Age and Roman settlement patterns, which change significantly across the project area. They can be roughly grouped into four main areas: the fen edge; the Bourn Valley; the claylands; and the chalkland south of the River Cam. In all cases the buried remains of settlements and boundaries were revealed as cropmarks and soilmarks on aerial photographs. The distribution and appearance of these marks appear to be largely defined by the underlying soils and geology.
Late Iron Age and Romano-British settlement
The cropmarks indicating settlement along the fen edge and in the bottom of the Bourn Valley are fragmentary, and show tracks flanked by enclosures. More complex settlement layouts occur at Fen Drayton, Histon and Cottenham, and in some cases dispersed enclosures and boundaries follow palaeochannels, relict waterways preserved as geological features.
The claylands were previously considered to have been largely devoid of settlement prior to the Roman period. Recent Historic England aerial reconnaissance has however revealed a landscape dotted with complex, multi-phased later prehistoric and Roman settlements. These settlements are defined by nucleated clusters of ditched enclosures of all shapes and sizes. Some have the distinctive funnel-shaped entrances of ‘banjo’ enclosures, whereas others are irregular in plan. In some enclosures the sites of round houses were indicated by the cropmarks of ring-ditches. The elements comprising these settlements appear to have accreted over time, although it is not clear how long these processes took.
The clayland settlements seem different from those in others areas as there is no evidence for communication networks or large-scale land division. The settlements were almost certainly connected but we are not certain why these tracks and boundaries are not visible. It may be that the routeways were hedged, though as clay landscapes are prone to water retention we would expect to see drainage ditches. Or it may be that the clays were largely wooded, with clearings for settlements, and passages through the trees. Yet another theory is that the claylands were a largely pastoral landscape, with no fixed routes or boundaries (Abrams and Ingham 2008).
South of the River Cam the settlement characteristics contrast considerably to those on the claylands to the north. The geology here, of chalk, sands and gravels, is mainly free-draining. Both the soils and the land use associated with these geologies are usually more conducive to the formation of cropmarks than with clay, resulting in a greater visibility of archaeology from the air.
Here, the survey has found extensive routeways, some over five kilometres in length, and often linking settlements. Use of these tracks in the Roman period is demonstrated by clear associations with villas, settlements and cemeteries at Gatley End, Litlington, Ashwell and Guilden Morden.
Evidence for Romanisation
Without dating evidence or morphologically-distinct settlement forms, indications of Romanisation are lacking on the clays north of the River Cam. However, there is strong Roman evidence across much of the chalk south of the river. There are numerous examples of such sites on a broad span of alluvial sands and gravels between Shepreth and Hoffer Bridge. Cropmarks east of Shepreth show a settlement defined by a complex arrangement of rectilinear enclosures, approached from the east by a broad double-ditched avenue. Limited excavation along the western periphery of the settlement has established dates from the 1st to 5th centuries AD (Maynard et al 1997).
This settlement is linked to the wider cropmark landscape by a series of boundary ditches and tracks extending to the south and east. The multi-phase complex of Late Iron Age and Roman features at Herod’s Farm and the villa site at Hoffer Bridge are of particular note, both linked by the network of routeways to the wider Roman landscape.
The importance of the river
It is evident from these distinct site morphologies that the River Cam was an important boundary in the Iron Age and Roman periods. While it is possible the river acted as a cultural boundary, the different settlement forms revealed by the survey are also likely to be related to the clay and chalk geologies of the area, which are largely separated by the river.
By the medieval period we see a more uniform pattern of settlement across most of the region, one that largely exists to this day. A farming regime of open-field systems predominated across the landscape and left ridge and furrow in its wake. Lidar reveals that great swathes of such medieval land divisions survive as earthworks. Defined by extensive sinuous and linear embankments, these ‘furlong boundaries’ continue to follow the natural lines of the topography. They formed the basis for post-medieval land division and were often not superseded until the enclosure acts of the early 19th century.
The project has emphasised the need to explore the landscape as a whole as well as to look at sites on an individual basis. It addresses one of the most archaeologically rich landscapes in the east of England and also supplies vital information in a region that is under development pressure. The north of the project area in particular has seen very large areas of development-led fieldwork, and the results complement the landscape-level survey reported here.
In the next phase of the NAIS project, it is intended to undertake smaller-scale ground-based work so that these discoveries can be better understood. Techniques such as geophysical survey could also help develop a better understanding of those areas which lack good evidence from cropmarks.
In general, the NAIS for south-west Cambridgeshire reveals a complex relationship between the natural environment and Iron Age and Roman archaeology, one which went on to influence the landscape through the medieval period and into the modern day.
The two companion NAIS projects on the Lakes and Dales and West Wiltshire are reported on in Historic England Research 3 these articles also explain a little more about the rationale for the surveys (Oakey et al 2016; Last 2016).
David Knight is an Investigator in Historic England’s Historic Places Investigation Team (East). Following a number of years employed in the private sector as an archaeologist and air photo interpreter he joined the Aerial Survey team of English Heritage in 2010. He leads the aerial mapping element of the NAIS for south-west Cambridgeshire.
Abrams, J and Ingham, D 2008 Farming on the Edge: Archaeological Evidence from the Clay Uplands to the West of Cambridge. Oxford: East Anglian Archaeology Monograph 123
Maynard, D J Cleary, R Moore, R Brooks, I P and Price, J 1997 ‘Excavations at Foxton, Cambridgeshire, 1994’, in Price, J Brooks, I P and Maynard, D J (eds) The Archaeology of the St Neots to Duxford Gas Pipeline 1994. Oxford: BAR British Series 255
Oakey, M Hazell, Z and Crosby, V 2016 ‘Revealing past landscapes in Cumbria and Lancashire’, Historic England Research 3. Swindon: Historic England
Last, J 2016 ‘The changing historical landscape of West Wiltshire’, Historic England Research 3. Swindon: Historic England
Also of interest...
Current Historic England projects use a landscape-based approach to identify and characterise archaeological features