The same property fits the star beta Centauri in the forty-second century and Rigel in the thirty-fifth. The Rigel case could not explain the choice of site, although the other might.
The West Kennet Neighbourhood. Silbury Hill
The East Kennet barrow, the later of the two neighbours, is now tree-covered, and has not been excavated in recent times. Except in orientation, it seems to resemble its neighbour: it is only a metre or so longer, there are signs of a sarsen burial chamber, and there are traces of flanking ditches. The barrow as a whole looks as though it might have been aligned on the rising of Rigel. On the basis of its direction, about 145°, it might be tentatively placed not far in time from the West Kennet barrow. In view of the sophistication of the latter it would be foolish to draw any conclusion about a cult of Rigel. Such might have lasted here until the building of the artificial mound at nearby Silbury Hill, however, for the star would have been visible from the top of that mound, rising over the East Kennet barrow in the late third millennium. Against this idea is the fact that the first stages of the construction of the hill had begun centuries before—but in the mid-fourth millennium, Sirius would have had the same property. There are too many imponderables about the height reached at various times for any specific claim to be made.
FIG. 34. The character of the internal structure of Silbury Hill.
It seems likely that when two monuments were involved in a stellar alignment, the star was seen from the newer and over the older of the two. (The converse arrangement would have been perfectly possible, of course.) The principle seems to be illustrated at West Kennet. The Sanctuary, a succession of concentric circles, first of timber and later of stone, was to the east of the long barrow, across the valley of the river Kennet, and on its own small hill. (Its name was one used by local people, according to Stukeley.) Robbed of its stone in the eighteenth century, the site was rediscovered and excavated in 1930 by Maud Cunnington. As seen from the centre of that succession of circles, the West Kennet barrow would have been in a direction about 8.5° south of west, and at about 0.5° altitude, slightly less than that of the spur of the hill behind the barrow. Aldebaran could have been seen setting over the barrow when the star’s declination was about –3.96° (taking its extinction angle of 2.0° as the deciding altitude). This was its value in approximately 2800 BC, a date compatible with other archaeological evidence relating to the early phases of the Sanctuary. There is a pair of post holes defining a diameter of the oldest structure (Sanctuary IA) in exactly the required line.
The most impressive of the monuments immediately surrounding the West Kennet barrow is Silbury Hill. Built on a spur of chalkland, its base is nearly 30 m below the level of the barrow, and yet the Hill rises 10 m or so higher. (Its top is currently about 3 m lower than the East Kennet barrow.) It is a cone, with steepest slope close to 30°—a gradient that was perhaps chosen deliberately for its ‘one in two’ property, one unit rise to two up the slope. Several exploratory tunnels have been dug into the hill, the latest of them by Richard Atkinson (1968–70), who suggested four phases in its construction. After the first two phases had been completed, the hill was still not particularly remarkable for its height. It is probable that there was never any primary burial there. Certainly none has ever been found, although some have suspected that the shaft from an eighteenth-century excavation destroyed signs of one. The third phase required a change of plan, resulting in a stepped cone. The stepping can still be easily seen by the casual observer. The last phase was an extension of the main ditch to the west, presumed to be for chalk to fill in the steps. The overall construction involved moving well over 300,000 cubic metres of chalk—less than would have been needed had part of its base not been the end of the spur of the natural hill—and those responsible for the third phase especially knew much about soil mechanics, for they gave it great stability through a series of internal walls, built out of chalk blocks, the resulting cells being then filled with rubble (see Fig. 34).
What was the final purpose of this extraordinary structure? Since it is thought to have been four or five centuries in the making, one need not suppose that its purpose remained unchanged. Attempts have been made to find an astronomical explanation for it. In 1902 the American writer Moses B. Cotsworth, in his Rational Almanack, suggested that it carried a colossal gnomon to cast shadows on the world’s largest sundial, marked out on the ground below. He was evidently influenced by the Rev. Edward Duke, who in 1846 had made it out to be the centre of a vast planetarium on which the planets were represented by ‘temples’ in the neighbourhood: Stonehenge was Saturn, Avebury was the Sun and Moon, and so on. One must be charitable to all enthusiasts, in the hope of being treated likewise. Sundials and planetaria are really no more exotic than the vision of one respected contemporary archaeologist, Marija Gimbutas, who sees the hill as ‘a gigantic representation of the Pregnant [Earth Mother] Goddess in a seated position’.17
There is a range of Silbury radiocarbon dates running from 2725 ± 110 down to 2145 ± 95 bc. The extremes of this range correspond to 3630 and 2500 BC in calendar years. Building probably began a century or so after the West Kennet barrow, an undertaking by the same group of people.
From Silbury Hill, the West Kennet barrow is nearer and more prominent than that at East Kennet. The place where it stands is such that looking over the head of the future West Kennet barrow from a point at the centre of Silbury Hill, Rigel could have been seen rising in the thirty-ninth century. The place of rising would gradually have moved to the forecourt area, and eventually off the scene completely, but at the date accepted here for the foundation of the present barrow, namely 3625 BC, beta Centauri rose precisely over the chamber as seen from the same point. An earlier long barrow near Windmill Hill (Horslip) is more or less on the same line, and the East Kennet barrow is near it too, so that many further possibilities are added to the list—for example, Rigel rose over the place of the future West Kennet chamber as seen from the Horslip barrow in 3710 BC. It might be thought that when barrows are not intimately related—for instance directed one towards another, as at Fussell’s Lodge—such alignments are best ignored. That they are part of a conscious strategy covering a much wider territory, however, will be demonstrated in the following chapter. (Maps will also be found there and in Chapter 6 showing the principal long barrows and other prehistoric remains in the West Kennet region. See Figs. 69 and 101.)
Beckhampton Road. Stars and the Sun
The long barrow off Beckhampton Road lies less than 4 km west of that at West Kennet. As mentioned earlier, it is one of an important trio excavated between 1959 and 1967—in this case in 1964 under the direction of I. F. Smith. It was described by William Stukeley in 1743 as ‘pyriform’ (pear-shaped), and ‘longish, but broad at one end’. It had been over 50 m long, and was originally flanked by splayed ditches, with its broad end roughly northeast. That end had been transformed when a round barrow