There was no published large scale (1:25,000) soils map for the study area and so a new map was commissioned (Figure 4.2). Existing data from survey work over part of the area in the 1970s was complemented with new augering in key areas not previously surveyed. This enabled the creation of a new map encompassing all three alternative sites for the battle and, fortunately, most of the area finally demonstrated to be the core of the battlefield. Two small supplementary areas were added later, to cover specific alluviated ground on the southern periphery of the battlefield.⁶

While all the soils data has some relevance to the study of the historic terrain and the taphonomy of the battle archaeology, it has been the alluvial soils, described here as the Fladbury Series, which has proved the key data set. It is only within this zone, where the soils developed in waterlogged conditions, that medieval wetland could have existed. These data show that there never was a marsh on the slopes of Ambion Hill. Instead they indicate two zones, set along the Fowlismere, Fen Hole and Fen Meadow streams as the likely focus of former wetland.

The soils evidence was complemented by the mapping of the medieval open fields, discussed below, which revealed the extent of medieval meadow (Figure 4.8). Together these two data sets provided a clear search area for the ‘marsh’, which was further narrowed down through the study of fen and related place names (Figures 4.12 & 4.13). Within the resulting zone a programme of palaeo-environmental investigation was then undertaken.

During our initial field inspection in 2004 an area of peat had been identified from molehills in Fen Meadow, which was subsequently confirmed by several auger holes made with the assistance of Dr Roy Bradshaw of Nottingham University. It was therefore expected that substantial peat deposits would be identifiable in the palaeo-environmental survey, enabling the former extent of wetland to be easily and accurately defined. However, the absence of any comparable evidence from the auger data of 1976 and 2006 should have given pause for thought, despite the relatively wide spacing of their sampling (Figure 4.6). They had identified a peat deposit in just one small isolated location to the south of Greenhill Farm, in a very narrow alluvial area very close to the course of the Sence Brook. This was more than 2 km to the east of the zone of fen and related names, but the peat proved to lie beneath a deep alluvial deposit, indicating that it dated to a period long before the late medieval and subsequent augering demonstrated there it was not part of a widespread peat deposit.