Three ox skulls were found more or less in the line of the ridge, which again gave rise to speculation that the ox heads, perhaps with skins and hooves attached, had been set up on posts penetrating the back of the barrow. There is no sign of Aldebaran here, but as it happens there is an independent case to be made out for a switch of bull symbolism to midwinter sunset.
The main disadvantage of the scaling posts of the old structures at Wayland’s Smithy and Fussell’s Lodge was that they required a transference of levels, not very difficult when structures were of wood, but more so with earthen mounds. In some way or another, a horizon had to be built up until it produced the desired effect—but strictly in accordance with the requirements of right-angled viewing. There would have been only minor difficulties with the progressive shaping of the artificial horizon, as the bays were filled in, one by one, until at last rising and setting were seen in the required directions. The main intellectual problem was quite different: it was that of settling the directions. To reconstruct the method it is necessary to make a conjecture as to the starting point. There is a strong sense in which Beckhampton Road is a Rigel barrow. Rigel is the brightest of the stars concerned, and the alignment on it belongs to the site in the pre-barrow period. Assuming, then, that this was the star from which the builders began, here is a potential procedure:
Some method or other is needed to establish the positions of a pair of ridge poles at equal heights and at right angles to the lines of view to opposed stars, northern and southern in this case. Once they were established, ditches could be marked out, if not extensively dug at this stage, with appropriate sections parallel to the ridge-poles. There was still a degree of freedom left to the architects, who would have tried to accommodate other stars in their length-wise barrow lines. The central portion of the line of stakes will be assumed to align on the setting of Rigel, and the other pair on Deneb and Bellatrix:
(1) The stake holes XX were arranged to be in line with Rigel’s setting.
(2) Fences of stakes, to which poles were tied as cross-pieces, were set at right angles to that first line, and a viewing ditch cut parallel to it, for sighting on Bellatrix. Horizontal poles were raised along the ridge line until the star rises at that level and in the direction set by the transverse stakes. Hides could have been draped over them to give an obscuring horizon. The lengths of such poles would have been between 1.5 m and 3 m, and their weight offers no problem. Infilling of ditch material to make a solid horizon might have begun at this stage—in slices almost the reverse of an archaeological dig.
(3) A provisional ditch was started for viewing Deneb. (Approximate positions were of course known all along.) Another ridge-pole, at precisely the same level, was varied in its orientation until Deneb was seen to set precisely at right angles to it. Fences of stakes at right angles to the Deneb ridge-pole could then have been set up to confirm the arrangement, with viewing directions again made more easily visible by poles tied along them. This established perhaps all remaining directions.
(4) Ditches could next have been completed and the fences largely filled in. An arch of spaced parallel poles, like stringers in the body of an aircraft, could have been tied to the rows of stakes, to define the barrow’s form, although the removal of the stakes from one section might have been thought necessary before an adjacent section was added. The curve of the arch might have been fixed by templates, curved perhaps like longbows, with tow. The builders’ job was to fill up the arch with the materials of the mound, and to dress it smooth in a suitable way—with marl, chalk gravel, and turves. Section by section the barrow was so assembled, its wedge-like shape guaranteed by the lines of the ditches.
FIG. 36. The overall plan of the South Street barrow. The three most important sections are combined into one, for convenience, at the right. They correspond to the broken lines A, B, and C on the plan. Lines of sight to the eyes of observers in possible viewing positions, at approximately the correct calculated angle, are shown on those sections—which are, however, not perfectly chosen for our present purposes. The diagonal line of stakes (D) crosses the entire barrow. The larger sarsens are marked on the plan (notably S), in their present positions. On section B, however, sarsen S is placed upright, as it might at one time have stood, even before the barrow.
Assuming angles derived from the same sort of astronomical analysis as used for earlier barrows, now for the setting Deneb in one direction and the rising Bellatrix in the other, the resulting profile of the barrow conforms closely with I. F. Smith’s estimates of the shape the barrow originally had. Pollen analysis showed that the barrow had been built in an area of grassland, but with arable and wooded areas nearby. This barrow was not on high ground, and the best of all possible motives for the relatively steep angles of view of those who looked across the barrow from the ditches was to observe the stars well clear of nearby trees—in this case 15 m trees further away than 75 m would have presented no problem except in the line of the barrow—that lay along an arable valley floor.
The last of the important trio of long barrows in this district is that off South Street in the parish of Avebury. It was erected in an area of arable land that had been cleared in the early fourth millennium BC. The surrounding country, predominantly woodland, contained hawthorn, oak, birch, elm, alder, pine, and other species, with all-pervasive hazel scrub invading the open pasture from time to time. It will be shown that this barrow was always extremely humble in outward appearance and material structure, and as an artificial horizon set rather low altitudes, but that it was high enough for sight-lines to clear nearby scrub and woodland. William Stukeley, in his book Abury (1743), described it as ‘broad and flat, as if sunk into the ground with age’; but broad and flat it had always been. Humble though it appeared, it embodied a most beautiful astronomical symmetry, and one that leaves us in no doubt that the people of Wessex were still actively developing their art.
The barrow was excavated under the direction of J. G. Evans in 1966–7. The road—South Street—runs across a corner of it, and the site has been much ravaged by time, not to mention proximity to the village. There are two large standing stones 120 m to the west of it, known as the Longstones, or Adam and Eve, but these belong to a much later period, as will be shown in connection with the Avebury avenues. Although there are no great quantities of stone in any of the three Avebury barrows, here at South Street there are several large and small sarsens at its principal end, and the larger stones were evidently set in place before the main construction, since all lines of stake holes curve round them where necessary. This barrow repeats in several respects the structure at Beckhampton Road, revealing a similarly straight row of stake holes defining an axis, and indeed more complete transverse rows than at that other barrow. The South Street barrow was divided by them into about 20 bays to each side of the axis. Again they were occasionally deformed in places by pressure of the mound, and again there were numerous traces of collapsed rods that had originally been fixed to them. There is a pair of ditches, uninterrupted in the South Street case, and splayed but not very markedly so. A simplified plan of the site as a whole is shown in Fig. 36, where rows of stake holes are represented by continuous lines (marking the axis and bays). Once again, those who dislike the element of approximation in all this may consult the original publication for the many hundreds of holes.
Applying the principle of viewing at equal altitudes, it is found that looking across the ditches, along the directions set by the bay-fences, Vega was observed rising in the northeast, and that Sirius was seen setting at an altitude of about 9° to the southwest. The date was in the neighbourhood of 3260 BC. A date seven centuries earlier, with Arcturus and Bellatrix, is rejected because it makes for an improbably high barrow, in fact over 5 m along the spine. The radiocarbon dates also speak against that solution.
This very general conclusion has to be qualified in several respects, since the large number of paired lines of stake holes means a large number of solutions, and not all are