Excavations 2010
In September 2010 excavations were carried out on Aylesbeare Common, Woodbury Common and Colaton Raleigh Common. Four sites were excavated as follows:
1. A pebble platform on Aylesbeare Common
2. A mound in a bog (the Bog Barrow) on Aylesbeare Common
3. A section through the burnt mound, Jacob’s Well, Woodbury Common
4. Excavation of a small cairn, Little Tor Barrow on Colaton Raleigh Common
The Aylesbeare Pebble Platform
During the summer of 1937 George Carter and his small excavation team, that included his three daughters, Priscilla, Ruth and Mary, carried out a series of excavations of mounds on the summit area of Aylesbeare Common, part of the East Devon Pebblebed heathlands. These low and discrete features had been discovered following swaling of the area in 1936. Carter excavated or part excavated seven mounds which he described as resembling a ‘keyhole’ in plan. They consisted of a small rectangular mound about 3 m long attached to, in some cases, a circular platform about 5 m in diameter. Excavation of the rectangular mounds revealed elaborate pebble platforms beneath of an entirely different shape. Two of them were in the shape of double-bladed ceremonial axes, tapering inwards at the centre and widening out at the ends but in a somewhat asymmetrical fashion. The other five platforms excavated by Carter were roughly trapezoidal in form, one short end of the pebble platform being significantly longer than the other.
The structures that Carter excavated were found on sloping ground dropping away to the north and the east down to a large amphitheatre shaped bog below the hill summit about 200 m to the north-east of the massive early Bronze Age summit barrow. In this same general area of Aylesbeare Common General Simcoe had set up a temporary encampment for his troops around 1799 at the time of the Napoleonic wars. Carter also excavated a few of these structures although he did not publish the results.
Carter maintained that the pebble platforms that he had excavated were prehistoric, of Iron Age date, and could be understood as part of a sacrificial cult (see Devon Proceedings 1938). But given a lack of artefacts associated with them and the absence of the technique of radiocarbon dating there was no possibility of dating them. For over seventy years no archaeological investigations have been made on Aylesbeare Common and Carter’s work and the spectacular finds he made have been almost entirely forgotten. Some have assumed that the pebble platforms were in all probability of Napoleonic date and constructed by Simcoe’s troops since they lack any direct parallels in either prehistoric Britain or Europe.
In September 2009 the East Devon Pebblebeds Project undertook field survey following swaling and undertook a small series of excavations on Aylesbeare Common in order to attempt to locate pebble platforms of the same kind that Carter had found but without success, although remains of Napoleonic date were discovered. Small areas were also cut in the spring of 2010 in areas where Carter had found his platforms but nothing came to light. It seems likely that the platforms Carter excavated are now destroyed, probably during military use of the area in World War II.
During 1996 the RSPB had undertaken topsoil scraping operations in a different area of the Aylesbeare summit: about 350 m to the north-west of the summit barrow. A series of damaged pebble platforms were uncovered and partly cleaned. One was almost intact. These were subsequently covered over again. The best preserved platform was uncovered in March 2010 by Toby Taylor of the RSPB and excavated during September by the Project team (Figs. 1 and 2).
Figure 1. The Aylesbeare Pebble Platform
Figure 2. Plan of the Aylesbeare Pebble Platform
The platform is made up of 1,337 multicoloured pebbles, 2.8 m long, 1.6m wide at the broader end and 0.8m wide at the narrower end. It is orientated NNE-SSW with two projecting ‘horns’ at the narrow NNE end. Larger pebbles, placed horizontally, make up the edges. A small section 24cm wide and 60 cm long was cut into the platform in an area that had already been damaged. This revealed that the pebbles inside were laid, like teeth, with their long axis placed vertically. They are of a fairly uniform size, between 5 and 15cm long. The section provided evidence of the manner in which the platform had been constructed. Clay was mixed with reddish sand forming a kind of cement that was laid on the grey natural soil surface and the pebbles were embedded in it end on with only the top showing thus providing maximum stability. Charcoal samples were recovered from a secure context under the pebble platform and from the orange material in which the pebbles were embedded when being laid. These provided two AMS radiocarbon dates from birch charcoal of 1460 to 1310 BC and 1390 to 1120 BC demonstrating that they are of Middle Bronze Age date.
The platform excavated in 2010 is very similar to some of Carter’s finds in terms of shape, size and orientation strongly suggesting that they were also of prehistoric date as he had maintained. The long axis of the horned platform is orientated towards Hembury, with its early Neolithic causewayed enclosure, one of the ‘horns’ in the direction of the Raddon Hills with another Neolithic causewayed enclosure (important hills of ancestral significance during the Bronze Age) and the other in the direction of East Hill and the rising sun around midsummer. Its intervisibility with the large early Bronze Age summit barrow on Aylesbeare Common only a few hundred metres to the east may also be of importance. It could form part of a ceremonial complex connected with the barrows ceremonial and mortuary rites taking place here. The platforms are of a size that can comfortably accommodate a body and might have been used as places of excarnation.
The shape of the pebble platform with its two ‘horns’ is most striking and it might be understood as anthropomorphic. General analogies can be drawn with a repertoire of anthropomorphic designs found elsewhere in Europe, with Bronze Age rock art motifs in Scandinavia, Copper Age schist plaque figurines from Portugal, and anthropomorphic designs on pottery, bronzes and pendants from the central and eastern European Copper and Bronze Age.
This is a unique find of international significance, as important, in its own way, as Stonehenge.
The Bog Barrow
The Bog Barrow is a mound made up of soil, surrounded by a ditch on the Aylesbeare Common. It is situated just below a slope north facing slope in a bog. The mound is six metres in diameter surrounded by a ditch and in the highest point it is 0.52m high.
George Carter cut a square section into the centre of the mound (0.8 x 0.8m) in 1937. He also cut a shallow trench across the mound surface from the centre in an easterly direction (now 0.1m deep), but did not finish it. The spoil was left on top of the mound on the northern side. Carter’s section drawing showed lenses of dark silty material in a yellow clay matrix. The only find he recorded was a large big red pebble in the bottom of his trench. He believed the mound to be prehistoric in date marking the site of a sacred spring. We decided to excavate the south-western quadrant of the mound in order to obtain dating material and information about its structure and purpose.
Course and results of the excavations
We cleared vegetation consisting of grass and much bracken from the mound surface and the surrounding ditch. At this stage the contours of the structure became clear and it could be precisely measured. It proved to be a perfectly circular mound 6m diameter with a surrounding ditch 0.9m wide.
The material on the top surface was very compact and hard, brownish-grey in colour and consisted of a mixture of soil, grit, and small pebbles, with irregular lenses of white and red sand and black soil. This context was 0.3 to 0.4m thick and when. Below that we discovered a 0.25m thick layer of soft, very fine grained, black soil with small flakes of charcoal (all of them were plotted). Below this we reached the natural surface. Except for charcoal we found no finds whatsoever. The ditch had a V-shaped profile. The width of its top varied between 0.9 to 1m and its sides between 0.35 to 0.45m and 0.79 to 0.84m. We found much charcoal in the basal ditch deposits but no other finds.
In the centre of the mound we found the remaining part of of a central pit, packed with small pebbles, through which Carter had dug his trench. The 33 charcoal samples recovered from the mound and the ditch was identified by Dana Challinor as mainly being oak. Much of this came from relatively small diameter roundwood. Two samples contained some heather/ling and one a quantity of hazel/alder. Four samples, two from the basal layers of the ditch and two from the basal layers of the mound were radiocarbon dated to around 1800 AD.
This result demonstrates that the mound was constructed by General Simcoe’s troops who at the time of the Napoleonic wars were temporarily stationed on this part of Aylesbeare Common. The central pit inlaid with a packing of pebbles was most probably the support for a flag pole deliberately situated in a discrete position on the margins of the bog. It lay below a double line of circular tent structures, with surrounding drainage ditches, on the lower part of the slope overlooking the bog whose presence was recorded by the antiquary Hutchinson around 1865.
Figure 1.
Aylesbeare Bog Barrow, view from the south-east, after the surface layer of turf and reddish-brown humic soil was removed. In the middle the Carter's square section is visible.
Figure 2.
Aylesbeare Bog Barrow, view from the south, The very differently coloured layers of context 3 and 4 are visible. Right: the receding part of the profile is part of the Carter's trench in the centre of the mound.
Jacob's Well
George Carter’s excavations at this site in 1938 revealed the presence of a wooden shrine below a burnt mound consisting of charcoal and fire cracked pebbles situated in a bog at the base of the western escarpment of the Pebblebed heathlands dating to the early/middle Bronze Age (see Jacob’s Well web pages). We decided to re-excavate part of the mound in order to obtain samples for environmental analysis, material for dating, and further evidence for its function and use. We excavated a 1m square trench in the centre of the mound on the western side of Carter’s north-south central trench. One immediate question was where Carter had deposited the spoil from his trench. This proved to be in two places: (1) immediately outside the mound on the southern side and (2) on top of the mound itself thus considerably increasing its height and altering its profile from being an oval flat topped mound to a much more rounded shape.
Since it was apparent from the side of our section running into the mound off Carter’s trench that there was no stratigraphy within the burnt mound deposits we decided to excavate by 10cm spits until reaching the basal peaty layer. The top 60-65cm of our 1m square section consisted of spoil from Carter’s excavations and at the bottom of the spoil we found the broken top of a glass lemonade bottle. Below this we found the undisturbed deposits comprising the burnt mound overlaying a basal layer of peaty soil that Carter had recorded in his section. The undisturbed burnt mound deposits were 80 cm in depth overlaying the peat layer which was 17cm in depth. Below this large pebbles occur in a natural grey clayey matrix (Fig 1).
Figure 1. The Section through the Jacob's Well burnt mound
The material from each 10cm spit, including Carter’s spoil, was excavated into buckets and weighed. It was then dry sieved using a 1mm mesh and charcoal samples were taken for analysis (Fig 2).
Figure 2. Sieving the material from the Jacob's Well burnt mound
The material was then wet sieved and the fire cracked pebble fragments were weighed. No finds were recorded and only a very few small quartz pebbles were found intact. The rest were very highly fragmented. A 2kg random sample of the broken fire cracked pebbles from each 10cm spit were individually measured (maximum length), weighed and examined for the presence of the cortex (smooth outer surface of the pebble) and this was recorded. The purpose of this was to enable us to distinquish whether any changes in the composition of the material was apparent from the top to the bottom of the burnt mound (e.g. more or less charcoal and sooty deposits or whether there might be proportionally more larger pebble fragments present at various depths through the burnt mound or a higher or lower degree of fragmentation of the pebbles).
We had chosen to site our section where there were no pine trees or tree stumps visible on the upper mound surface. However an old and heavily rotten pine tree stump that must have been growing on the top of the mound in Carter’s day emerged as we excavated down through his spoil that had concealed it on the mound surface. In the peaty soil beneath the burnt mound we found and recorded wood deposits. Subsequent analysis of these showed that they were heavily decomposed root wood. They almost certainly were the roots of the tree discovered in the section. Within the peat horizon three units could be distinguished:
3-5 cm: light brown peaty layer, possibly burned
5-7cm: an irregular sinuous black band that on subsequent analysis proved to be a tar layer
7-17cm dark brown peaty layer.
There were no artefacts in this layer. A sample was taken for environmental analysis. Preliminary results of a pollen analysis show that common alder dominated the wetland environment, prior to the formation of the burnt mound, with an understory consisting of hazel, willow, ivy and holly. Grasses and sedges dominated the ground.
The fire cracked pebbles and the significance of the burnt mound
Analysis of the excavated material shows that there is a substantial difference between Carer’s spoil and the undisturbed burnt mound deposits beneath. In the spoil the percentage of pebbles was considerably lower varying between 53% and 65% of the total (mean frequency 59%). In the other undisturbed spits the pebble frequency was much higher, up to 81% (mean frequency 73%). The proportion of pebbles in relation to ash and charcoal did not differ substantially between the 10 cm excavation units and there was no discernable trend apparent within the burnt mounde such as the proportion of pebbles increasing or decreasing with depth.
The size of the crushed pebbles was assessed by weighing and measuring the maximum length of the fragments of a 2kg random sample from each excavation unit. The vast majority of the fragments throughout weighed 50 grams or less (83-99%). In all the spits only one or two fragments weighed more than
150g. The percentage of larger fragments measuring 4cm or more in length was low in the undisturbed spits varying between 5 and 10%. Larger fragments were more common in Carter’s spoil and, interestingly, the two basal levels of the burnt mound where they made up between 18 and 25% of the pebbles. This seems to indicate that the intensity of fire cracking of the material increased after an initial stage and then remained more or less constant throughout the period of use of the mound for fire cracking rituals. The pebbles destroyed at Jacob’s Well were relatively small in size, no more than 10-15 cm in length and originally weighing 500g or less or about the same size as the majority from the Tor Barrow cairn excavated on Colaton Raleigh Common. The closest possible source would be the bottom of the western escarpment of the Pebblebed heathlands only **m distant from the eastern end of the mound, but some might have been brought from much further afield.
Throughout Carter’s spoil and the undisturbed spits the number of complete or whole pebbles was less than twenty. And these were recovered from only a few of the 14 excavation spits. This miniscule frequency may be compared with up to two hundred or more pebble fragments from each 2kg sample and the total weight of pebbles from each 10 cm excavation unit being up to 145kg. These were all very small quite unremarkable quartz pebbles that had survived the fire and appear to be of no other significance whatsoever.
Each pebble fragment from the samples was examined to see if any of the cortex or smooth outer surface of the pebble remained. The frequency of the fragments on which the cortex was present varied between 38% and 61% (mean 48%). The spits with the highest frequencies (59 and 61%) occurred just above those making up the basal level of the mound where interestingly enough the proportion of pebble fragments greater in length than 4cm was considerably smaller.
It should be noted that the presence of an area of remaining cortex on most of the pebbles was by no means obvious and could only be detected by close examination of each fragment.
The intention was clearly to utterly destroy the pebbles. The fire cracking process reduced the pebbles to an irregular and jagged gravel resembling railway ballast or any kind of crushed stone. In the process the pebbles became unrecognizable as pebbles. They were utterly destroyed. Not only did they loose their individual shapes and smoothness but also their colours. The material is almost all a uniform dull grey colour even when washed to remove the soot covering their surfaces and blackening them to such an extent that they resemble pieces of coal or charcoal. Sometimes when wet sieving the pebbles we initially misrecognized some very small fragments as charcoal and vice versa.
The similarity of the material to charcoal is worth commenting on further. The process of pebble destruction can perhaps be understood as a transformative process turning stone into charcoal, itself the product of another transformative process involving the burning of wood. Once wood is burnt and only charcoal remains the type of tree from which the wood came is no longer recognizable. All charcoal looks the same, except of course in the microscope of the environmental scientist. The fire rituals at Jacob’s Well can be understood as producing an end product in which both wood and stone became symbolically reduced to a state of sameness in which the different qualities of both substances became erased. The fire rituals consumed and transformed both wood and stone into a blackened material resembling neither of them. These rituals took place in the context of a bog in which water was poured over both to produce steam rising up from the mound as a cloud of vapour to ultimately disappear into the heavens above. Thus substances that were solid and material (wood and stone) became ultimately transformed into the immaterial, an essence.
Reflecting on the ritual destruction of the pebbles at Jacob’s Well we can draw clear parallels with the destruction of metalwork in the middle and late Bronze Age, often deposited in bogs, and practices of cremation taking place at the same time reducing the body to self-same fragments of bone through a fire ritual. Just as the individual pebbles at Jacob’s Well lost their individuality of form, their self-identity, so did the corpse and the bones of the body. Pebbles and people are being treated in exactly the same way and both pebbles and people, when considered collectively, are both same and different.
Further work in progress
Quartzite is an extremely hard material and extremely difficult to fragment and break. The degree of attrition of the material at Jacob’s Well is quite extraordinary. We attempted to fire crack pebbles in a bonfire on several occasions both letting them cool naturally and by dowsing and submerging them in water. These experiments only resulted in a few large cracks across some of the pebbles. We conclude from this that the pebbles at Jacob’s Well must have been heated up at a far higher temperature than is possible in a normal bonfire. This might require some form of kiln or technology associated with firing ceramics or smelting metal. We will be conducting experiments to verify this.
We now have (june 2011) new radiocarbon dates for Jacob’s Well. The top of the burnt mound deposits below Carter's spoil is dated to 1300BC and the bottom 1400BC so the mound took one hundred years (or three generations) to accumulate. There were in all probability two main phases of human activity at Jacob’s Well: (1) An early to middle Bronze age phase in which a shrine was built on the site; (2) A later middle Bronze Age phase during which the pebbles were cracked and the burnt mound deposits accumulated. The presence of the tar layer in the peaty deposits beneath the mound strongly indicates that the pebbles were burnt and fire cracked in situ rather than elsewhere. Radiocarbon dates from the top and bottom of the peat deposits beneath the burnt mound will tell us the time scale over which these peaty deposits and their preserved vegetational sequences, revealed by the pollen analysis, accumulated and whether there was a significant gap between the period of peat formation and that of the overlying burnt mound deposits.
Little Tor Barrow
Little Tor Barrow is a small round pebble cairn on the Colaton Raleigh Common. The cairn is situated on the western side of a low spur between two valleys only a few metres to the south-east of Tor Barrow (see excavations 2009 page). These two barrows are aligned towards Midwinter sunrise. We now have six radiocarbon dates for Tor Barrow, three from underneath the periphery of the cairn and three from a central pyre dating it to 2000 BC.
During the 2009 excavations the surface of Little Tor Barrow was cleared of vegetation and the humic soil covering it removed revealing a small pebble cairn and we excavated the south-west half. Apart from a few flint flakes no finds were made and no charcoal was recovered that might allow us to date it in relation to Tor Barrow. Consequently during 2010 we decided to excavate the north-eastern half of the cairn. The size of the excavated part was 2.65 m in diameter (NW-SE) and 1.4 m to the perimeter (NE-SW) direction (Fig 1). We excavated the cairn pebble layer by pebble layer from top to bottom recording the pebbles from each layer. The excavated half of the cairn was divided into north and south quarters. Each pebble layer decreased in diameter as we proceeded to excavate. In all there were five main pebble layers in this part of the cairn separated by thin grey sand deposits. In the centre there were a further three pebble layers covering a small area only about 0.5m in diameter. There is no evidence that this marks a distinct phase in the cairn construction.
In all we recovered 36 charcoal samples for identification and radiocarbon dating. Subsequent analysis showed that oak was overwhelmingly dominant and no roundwood was noted. The only material that proved suitable for dating was a single fragment of alder or hazel charcoal. This was from a basal level of the cairn near to its centre. This provided a date of between 1730 to 1720 BC and 1690 to 1510 BC, i.e. it is of Early Bronze Age date and about 300-500 years younger than the larger adjacent pebble cairn, Tor Barrow.
On completion of the excavation the cairn was reconstructed by laying levels of pebbles and soil. The surface of the cairn was finished with a stripe of yellow pebbles on the south-east side pointing in the direction of the midsummer sunrise and a ring of red pebbles on the top with white quartz pebbles at the centre (Fig 2).
Figure 1.
Little Tor Barrow: excavation units and orientation.
Figure 2.
The reconstructed cairn with Tor Barrow in the background.
