West Kennet Palisaded Enclosures - aerial survey 2013 update

West Kennet Late Neolithic palisaded enclosures (from J Leary, D Field & G Campbell (eds) 2013 Silbury Hill. The largest prehistoric mound in Europe (English Heritage, Swindon), pp234-5 & fig 8.2) The complex at West Kennet has been mapped from aerial photographs on four previous occasions, the most recent episode occurring in 2002 (Barber 2003; Barber et al 2003). Since then, further reconnaissance photography by Damian Grady of English Heritage in 2004 has led to revision of the 2002 mapping. Unusually, analysis of the 2005 aerial photographs has allowed not only for the addition of extra detail but also for the removal of features previously considered to be of possible archaeological origin, in the process raising questions about the sequence of construction of the various palisaded elements of the complex. The mapping in 2002 occurred as a result of new cropmark detail being photographed from 2000 onwards during regular flights undertaken to monitor the condition of Silbury Hill from the air. These photographs also confirmed a number of cropmark features which had been mapped during the AWHSMP as a result of the re-analysis of existing photographs (see Barber 2003 for a full discussion). The two large enclosures were identified through a programme of excavation undertaken by Alasdair Whittle from 1987 (Whittle 1997), although Enclosure 1, the eastern enclosure, had first been photographed as a cropmark in 1950, while part of Enclosure 2 is visible as a cropmark on an oblique in the NMR’s Crawford Collection dating from the 1930s. Subsequent analysis of aerial photographs for the AWHSMP and of those taken from 2000 onwards has both added to and refined existing knowledge of the complex. The principal features of the West Kennet complex have been described in detail (in Barber 2003) and in a more summary fashion (in Barber et al 2003). Here it is proposed to focus on the adjustments made to the existing mapping in the light of the 2004 reconnaissance photographs (NMR 23398/01, 23398/08-9, NMR 23398/12-13, all taken 17th May 2004). These mainly centre on Outer Radial Ditch 3 and features directly associated with it. In 2003, it seemed possible that a linear feature extending northwest from outer ditch of Structure 5, the circular enclosure towards the southern end of Gunsight Lane, and the two shorter lengths of linear ditch crossing the eastern side of Palisade Enclosure 2 in a NNE-SSW direction, actually comprised three sections of a single linear feature. The 2004 photographs make this far more likely. The section leading from Structure 5 can now be seen to continue further to the northwest, the cropmark fading from view only as it approaches the field boundary. Likewise, on the other side of the same field boundary, the linear reappears in the crop much closer to the edge of the field than on previous occasions, before changing direction and crossing the interior of the enclosure. Inside Enclosure 2, what previously seemed to be two distinct sections of linear can now clearly be seen to comprise a single feature, and can be shown to continue a little further NNE than had been thought previously, again disappearing from view only as it approaches the edge of the crop. In 2002, it was suggested that within Enclosure 2, the linear seemed “likely to be continuous, the cropmark only interrupted by vehicle tracks and cropmark damage” (Barber 2003, 30). However, while the 2004 photographs have confirmed this to be the case, there remains one small interruption in the course of the linear. Around 7 metres south of Structure 2 there is a definite gap circa 1.8 metres wide. Structures 2 and 3, circular timber structures examined by Whittle during his excavations do not continue west of Outer Radial Ditch 3. In the 2004 photographs, their cropmark traces clearly end against the latter, suggesting that they were built up against the timber palisade presumed to have stood within it. Meanwhile, features A1 and A2, mapped for the AWHSMP and again in 2002, but described at the time as not being “wholly convincing as archaeological features” (Barber 2003, 24) have now been discounted as being of archaeological origin. They had been mapped as semi-circular arcs extending from the outer side of the palisade ditch of Enclosure 2, one either side of Outer Radial Ditch 1. Their complete absence from the 2004 photographs supports the doubts raised in 2002/3. The problems over features such as A1 and A2 highlight a further difficulty with aerial photography at West Kennet. As noted previously, “although the outlines of the major features are quite clear…the finer detail is more problematic. For all fields concerned, frequent darker patches of deeper soil either obscure archaeological cropmarks or prevent their formation…The tendency of these darker patches to form circular or curvilinear shapes means that in some places it is extremely difficult to decide whether certain patches are of archaeological or natural origin”. At present, the bulk of the interior of Enclosure 2 seems devoid of archaeological features. It is not, however, devoid of cropmarks – the problem is that none of those cropmarks resemble anything that can be mapped with any certainty as being of archaeological origin. It should be added at this point that none of the mapped features at West Kennet can be seen on the available lidar data. The detail added and removed in the light of the 2004 reconnaissance photographs reinforces the suggestion made previously that “all sorts of games can be played with the current plan and excavated evidence in order to try and tease out” a sequence of development for the complex (Barber 2003, 33). Certainly, this new plan further supports Pollard and Reynolds (2002, 115) suggestion that “the outer lines of palisade around structures 2 and 3 look less like contemporary elements and more like secondary features that are subsequently enclosing” their respective inner settings. We can, of course, add that the outer palisades of Structures 2 and 3 seem likely to post-date Outer Radial Ditch 3, which in turn may well be later than the Enclosure 2’s palisade. Beyond this, though, it is difficult to go at present. For now, airborne remote sensing alone has probably taken us as far as we can go with this particular site. References Barber, M (2003) Late Neolithic Palisade Enclosures at West Kennet: Report on the Aerial Photographic Transcription and Analysis. English Heritage Aerial Survey Report Series AER/1/2003 (Swindon: English Heritage) Barber, M, D Grady, H Winton (2003) ‘From Pit Circles to Propellers: recent results from aerial survey in Wiltshire’. Wiltshire Archaeol Nat Hist Soc Mag 96, 148-160 Pollard, J & A Reynolds (2002) Avebury: The Biography of a Landscape (Stroud: Tempus) Whittle, A (1997) Sacred Mounds, Holy Rings. Silbury Hill and the West Kennet Palisade Enclosures: A Later Neolithic Complex in North Wiltshire (Oxford: Oxbow Books) N Ke nn 411300 1989 excavations 411200 411100 1997 watching brief 411000 410900 410800 410700 410600 410500 168300 et 168200 Inner radial ditches 1 & 2 Palisade Enclosure 1 Palisade Enclosure 2 Structure 3 168100 Structure 2 Structure 1 Outer radial ditch 2 168000 Outer radial ditch 3 Outer radial ditch 1 167900 Structure 4 Plough-levelled round barrows 167800 Structure 5 West Kennet Long Barrow 167700 167600 167500 0 25m 250m Scale Scale1:5000 1:500