New Features within the Henge at Avebury, Wiltshire: Aerial and Geophysical Evidence

Article excerpt

The hot and dry summer of 1995 once again proved the value and cost-effectiveness of aerial survey. Numerous parchmarks were a product of the dry conditions throughout England, but especially in chalk grassland, and they revealed important new archaeological information. A parchmark within the great Neolithic henge at Avebury identifies a new subterranean feature, confirmed by geophysical survey, which fills in further details of the Avebury enclosure.

William Stukeley (1687-1765), one of Avebury's earliest chroniclers, described the great henge at Avebury as 'the noblest monument, which is probably on the face of the globe' (1743: 37). Despite the attention it has received over the last 300 years (Crawford & Keiller 1928; Smith 1965; Burl 1979), the corpus of information for this great earthwork and its stone circles, is inadequate (Ucko et al. 1990; Pitts & Whittle 1992). The recent discovery by aerial survey of an entirely new structure within the henge emphasizes the need for continued investigations at all nationally important sites [ILLUSTRATION FOR FIGURE 1 OMITTED].

Aerial survey

The drought conditions of 1995 and the discoveries made throughout England have been published already (Featherstone et al. 1995); here we are able to report on a particular discovery within one of Britain's most famous and important monuments. One of the challenges of aerial survey is to keep making new discoveries and it should no longer be a surprise that sites such as Avebury still have archaeological features within them which remain to be discovered.

The earliest aerial photographs of Avebury held in the National Monuments Record were taken on 22 June 1924, the most recent on 8 February 1996 (in exceptional snow conditions). In this 72-year period Avebury and its environs have been surveyed from the air frequently (there are 416 oblique photographs of the site in the NMRC alone), but until August 1995 no aerial photograph showed cropmarks or parchmarks within the henge from which an accurate map could be made (although some parchmarks were photographed in 1989 by the National Trust Warden). The marks, visible on 11 August 1995, were even clearer on I September 1995 when Roger Featherstone was flying with a BBC TV film crew and PLATE 1 was taken. There were also reports in 1995 that the parchmarks were visible on the ground (as they had been in 1990, [ILLUSTRATION FOR FIGURE 2 OMITTED]) and some were also surveyed by the National Trust in 1995. The intensity of the drought in 1995 meant that the buried ditches, in a chalk subsoil, produced negative cropmarks in grass (PLATE 1; see also Featherstone et al. 1995: plate 4). This is because of the particular drainage characteristics and particle size of the chalk (Wilson 1982: 55). The grass on the crest of the bank also parches out; in a drought this is a result of the lack of water throughout the growing season.

The parchmarks that excite particular interest are in the northwestern quadrant: a double-ditched curvilinear feature seen beyond the western end of the garden of The Lodge and (faintly) in the garden itself [ILLUSTRATION FOR FIGURES 2 AND 3.4 OMITTED]. There appears to be an inner feature, possibly rectangular, which may have a central pit for a post or stone. Three stone holes of the Northern Inner Circle immediately to the east of the new enclosure, are also visible; these were located by a previous geophysical survey (Ucko et al. 1990: plate 67A). In the northeastern quadrant, parchmarks of a further 11 stone holes of the Northern Inner Circle are seen, four of which were recorded during a survey of the earthworks carried out by the RCHME in 1990, and several by previous geophysical survey (Ucko et al. 1990: plates 67A & 73).

In the Outer Circle, 17 stone holes are visible as parchmarks in the northeastern and southeastern quadrants of the henge. In the southeastern quadrant there are 10 possible stone holes of the Southern Inner Circle visible as parchmarks. …