Stonehenge a New Understanding (37 page)

The King Barrows are splendid things to see, some of the largest round barrows in Britain. Protected beneath huge old trees, none has ever been investigated. When the 1987 hurricane blew some of the trees down on top of them, Mike Allen got the chance to look inside these newly created tree holes.
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He discovered that many of this group of Bronze Age barrows were built not of chalk but of turf and topsoil. To produce enough turf to cover each barrow mound would have required the stripping of six hectares (15 acres) or more of grassland. It must have been a clumsy, difficult job to strip turf with antler picks. This prehistoric turf-stripping would also have put out of use a large area of valuable grazing land, as if the purpose of this part of the funeral ritual was to cut off one’s nose to spite one’s face, economically speaking.

The avenue then continues down the east side of the King Barrow ridge, curving southeastward and passing through another two lines of less impressive round barrows. Eventually it reaches the Avon.

We had two main questions we wanted to answer. The avenue is 22 meters wide, with a ditch and internal bank running along each side, parallel to each other. There were originally also external banks, but these
are no longer visible. The internal banks are today only 0.3 meter high at their greatest. The ditches are 0.3 meter deep now but were once over a meter deep. As for the avenue’s curious elbow, it seemed possible to some archaeologists that the part of the avenue that heads off eastward toward the river was constructed in a second phase, after the section that leads northeastward from the entrance to Stonehenge. We wanted to find out for sure whether the avenue’s ditches had been extended in a second phase of construction, or whether the entire avenue had been built all at once.

The Stonehenge Avenue turns sharply eastward at a point known as the elbow. We reopened Atkinson’s trenches here to check whether the avenue was built all at once or in two stages. Stonehenge is on the horizon (center).

The second question was whether there was an earlier, short avenue lying under the present one, running along just the 500-meter-long solstice-aligned length from Stonehenge to Stonehenge Bottom. One of Atkinson’s photographs and his section drawing show a series of small
gullies within the avenue, running parallel with the avenue ditches but apparently underneath the avenue’s banks. These gullies appeared to be generally about 30 centimeters wide and up to half a meter deep, too large to be ancient cart tracks but not big enough for ditches. They were also visible on the geophysics plots, showing up as some seven parallel lines running along the solstice axis of the avenue. We puzzled over them, wondering if they were palisade slots to hold rows of posts, perhaps dividing the celebrants into lanes as they approached Stonehenge.

Down at the avenue elbow, California Dave’s team emptied out Atkinson’s trenches, and we were allowed to extend them a little to get a better cross-section of the avenue. There were very few finds, just a handful of worked flints from the new trench extension. The stretch of avenue in which we were most interested was where the magnetometer survey had shown a kink in the ditches, suggesting that a new stretch of avenue had possibly been tacked on to the end of the 500-meter-long straight section. In reality, we could see on the ground that there was no such deviation; the bend joined seamlessly with the straight section. It had not been added at a later stage. We also discovered that the avenue ditch, on both sides, had been cleaned out in prehistory after it had silted up. Although the team found nothing to date this event, radiocarbon dates on bones and antler picks from previous excavations date the cleaning-out of other lengths of the avenue ditch to around 2200 BC.

In 1978, one of Atkinson’s and Evans’s trenches had cut into a small raised feature immediately east of the avenue. This is called Newall’s Mound, after Hawley’s assistant.
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It consists of a deposit of heavy clay mixed with natural flints, which continues to a depth of 1.5 meters. It is disgusting stuff to dig out with a pick and shovel—just emptying Atkinson’s and Evans’s backfill was bad enough—but John Evans must have enjoyed himself immensely while excavating it the first time. It is a periglacial feature, a large solution hole, about five meters across, that has filled with a mass of clay-with-flints created in ice age conditions not far south of the glacier’s limit. Here was a textbook example of a geological feature of the sort John loved. It contained a buried early post-glacial soil and had been thoroughly bioturbated (the layering had been mixed up by biological action—in this case tree roots).

Mike Allen and Charly French were delighted to see the re-excavated solution hole. Both had been John’s students and knew it well from his lecture slides. Then they noticed something that John had missed. Deposits of clay-with-flints, recalcitrant though they are for the digger, are too soft to withstand the forces of natural erosion and normally form flat layers rather than raised mounds. Something had held this deposit together as a raised prominence, and the answer lay in the bioturbation. They could see where the roots of long-vanished trees had twisted and inverted the stratigraphy of the clay-with-flints; one or more large trees had stood on this spot in the early post-glacial period, their roots clutching the clay-with-flints like an eagle’s talons. This must have been why the deposit survives as a mound. Whether such trees were still standing when Stonehenge was built is anyone’s guess, but even treeless the mound would have been a visible natural feature at the end of the straight length of avenue. Maybe its position in relation to the avenue turn is not entirely coincidental.

Closer toward Stonehenge, things were going smoothly but not producing what I’d expected. Here we were reopening another Atkinson trench on the Stonehenge Avenue, just 30 meters from the Heel Stone, directly across the road from Stonehenge itself. We had found the outline of the old trench and marked out the two-meter-wide extension that we had permission to dig adjacent to it. The old backfill was full of finds—flint flakes, sarsen hammerstones, sarsen chippings, and bluestone chippings—as if nothing much had been collected during the 1956 excavation.

When we got to the bottom of the old Atkinson trench, we found that the gullies we’d seen in the old site photograph were not palisade slots after all. They weren’t even man-made. Here were more periglacial features, this time long, thin erosion gullies created by freeze-thaw conditions and filled with sediment formed from the grinding of chalk by ice into a clay “flour.” The Wessex chalklands are covered in these periglacial stripes and we were not the first archaeologists to be misled by these features of geological origin. Normally they are much shallower and narrower, often resembling plowmarks. I was disappointed that they weren’t man-made, but perfectly happy to change my mind—you always go with what the evidence tells you. We were victims of a geological coincidence. Because these periglacial gullies are aligned on the midsummer sunrise/midwinter sunset solstice axis, we’d wrongly assumed that they would
not
be geological.

When Mike and Charly took a look, they became very excited. The periglacial stripes are unduly wide for what might be expected here. The reason for their size is that water had been channeled from further up the slope between two low banks of natural chalk bedrock. With a lot of water available for the freeze-thaw processes that formed these gullies, their widths and depths are greater than is usually seen on this geology. Mike and Charly went on to point out that, in the early part of the post-glacial period, these gullies would have been very plain to see; they would have been clearly visible as stripes in the thin grass cover on the slowly developing soil. By the Neolithic period, they would not have been so noticeable, being covered by thicker soil and grass, except in times of drought when the parched chalk of the bedrock would have turned the grass yellow while the damper fill of the sediment-filled gullies remained green, leaving dark stripes on top of the gullies.
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Such dry periods would be most likely in summertime.

I had thought that the two natural ridges on either side of the gullies were created by the differential weathering of chalk bedrock: It has remained higher where it has been protected for thousands of years by the avenue’s banks. Mike and Charly pointed out that the man-made banks are actually very narrow compared to the widths of the natural chalk ridges beneath them: The presence of the man-made banks cannot account for the creation of such prominent natural features. Looking more carefully at the landscape, we could also see that the natural pair of ridges ran for only about 200 meters, whereas the avenue banks continued on well beyond them.

We had stumbled upon the reason why Stonehenge is where it is. The northeast entrance of Stonehenge is positioned at one end of a pair of natural ridges, between which are parallel stripes of sediment-filled gullies and chalk bedrock. It is not particularly unusual for Neolithic monuments to incorporate such aspects of the natural world into their design, but what is exceptional here is that this particular natural feature,
by sheer coincidence, is aligned on the solstice axis. There is absolutely no doubt that the builders of Stonehenge were aware of the presence of this geological formation, because they enhanced the two natural ridges by digging the avenue’s ditches along their outside edges and heaping soil on top of each ridge to form parallel banks.

This explains why the Stonehenge builders were so concerned to mark the solstice alignment of midwinter sunset and midsummer sunrise in the monument’s architecture: It was already inscribed in the ground. Perhaps this is also why, in Stonehenge’s earliest use, wooden posts were set up to reference major standstills of moonrises and moonsets that would be best seen at midsummer and midwinter full moon.

The natural ridges would have formed what anthropologists call an
axis mundi
, an axis or center of the world. For Neolithic people, this was where the passage of the sun was marked on the land, where heaven and earth came together. Such a place might have been regarded as the center or origin of the universe. It would certainly have been worthy of celebrations involving the transport of Welsh bluestones and, later on, the huge sarsens.

The presence of these natural ridges may also explain why there are Early Mesolithic postholes under the parking lot. During that period, ten thousand years ago, the periglacial stripes would have been easier to see under the thin vegetation on shallow soils that had only started forming after the Ice Age, and the ridges would have been more prominent than they are today after millennia of weathering. Perhaps this is why this particular spot was important enough for Mesolithic people to mark its environs with huge pine posts.

Many archaeologists were skeptical about our solstice-aligned natural feature. It was just too good to be true. How could we really prove that these parallel ridges were geological, subsequently enhanced by human construction? Yet this was by no means the first time that archaeologists had noted evidence for the use of natural features by prehistoric people. Almost a decade earlier, archaeologist Richard Bradley had written an entire book on the ways that prehistoric people throughout Europe took natural places—springs, rivers, caves, and mountains—to have sacred significance.
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These appropriations of the natural world could take a number of forms: placing of votive deposits, carving of rock art, extraction
of raw materials for tools, and resculpting of natural landforms. He had noted that the people of the British Neolithic were no exception to this wider picture. Like other cultures ancient and modern, they invested the world around them with special meanings, singling out certain hills, rivers, and other topographic features by leaving human traces that cannot be explained by mere practical activity and expediency alone.

We had already encountered similar re-use of a natural feature at Durrington Walls, with its avenue of rammed flint constructed on top of an entirely natural surface of exposed flint fragments that had formed in the bottom of the dry valley, or coombe, that ran from the Southern Circle to the River Avon. In that particular case, the avenue builders had added a new surface on top of the existing, natural one, incorporating animal bones, pottery, flint tools, and burned flint among the naturally shattered flint that formed the matrix of the avenue’s surface. Not only that, but Clive Ruggles had also shown that the alignment of this artificially enhanced natural surface was within one degree of the midsummer solstice sunset. Perhaps the very reason for the location of Durrington Walls was this freak of geomorphology, in which a natural bed of broken flints was almost perfectly aligned on the midsummer solstice sunset.

Could a similar natural coincidence also have dictated the placing of Stonehenge? To learn more about the chalk ridges and the deep periglacial gullies between them, Mike Allen consulted a chalk-geologist colleague, who came back with the suggestion that we should see if the two ridges showed up on radar mapping. Around the same time, Colin noticed on an aerial photograph of Stonehenge that there was yet another ridge here; a third ridge runs parallel to the other two but further to the east. Kate Welham’s geophysics team was sent out to survey it to make sure that there was no trace of associated man-made features: It registered a complete blank. We were then lucky enough to be approached by a Dutch radar company, GT Frontline, who brought their equipment over to Britain and surveyed the avenue. Their results confirmed what we’d hoped: There are indeed three parallel ridges which show up on the computer plot.