Silbury Hill, located just south of the village of Avebury in Wiltshire, is a massive artificial mound with a flat top. It is approximately 130 feet (40 m.) high, with a base circumference of 1640 feet. It is composed of over 12 million cubic feet (339,600 cubic m.) of chalk and earth and covers over 5 acres (2 ha). Silbury Hill occupies a low-lying site and except at certain points in the landscape (notably from the West Kennet Long Barrow from which this photograph was taken), it does not protrude significantly above the horizon.
It was built in three stages, the first begun around 2,660 B.C.E. The last phase comprised the building of six concentric steps or terraces of chalk which were then covered with chalk rubble, flints, gravel, and finally soil to form a cone-shaped mound. Each of the six steps was concealed within the overall profile of the mound, except the last one at the top which was left as a terrace or ledge about 17 feet (5 m.) below the summit. This terrace is clearly visible on the eastern side of the mound, but less distinct from the west.
Various legends have been attached to Silbury Hill. Folklore has claimed it to be the burial place of an otherwise forgotten King Sil (or Zel); of a knight in golden armour; and even of a solid gold horse and rider. It is also told that the Devil was going to empty a huge sack of earth on the town of Marlborough, but was forced to drop it here by the magic of the priests from nearby Avebury. According to William Stukeley, the top of the hill was dug into in 1723 and some bones were discovered together with an ancient bridle. The mound was again dug into in 1776 and in 1849. In 1967, excavations were undertaken by Richard Atkinson but again neither burials nor any clue to the mound's meaning were discovered. Atkinson did learn, however, through radiocarbon analysis that the mound dates to around 2660 B.C.E. Further evidence from the remains of plants and insects indicated that the structure was begun during the first week in August, probably at the time of the Celtic festival of Lugnasadh (or Lammas) at the start of the harvest season.
When seen from the West Kennet Long Barrow (as in the view at the top of this page), the summit of Silbury breaks the horizon at the line of the terrace.
Silbury also appears prominently in Stukeley's drawing of the 'great stone serpent of the Avebury complex. The very top of the mound can also be discerned from the village of Avebury in what has been described as a precise geomantic relation with the so-called 'Obelisk' in the Avebury complex. It can be seen, however, only after the crops in the intervening field on the horizon have been harvested; the standing grain is sufficient to obscure the view. For some, this is further evidence for interpreting the mound in connection with harvest festivals.
The original purpose of Silbury is unknown, although various explanations have been put forward over the years. Recently, Michael Dames has suggested that the hill is a symbolic effigy of the ancient Mother Goddess and is to be associated with fertility rituals which marked the course of the year. The festival of Lugnasadh (or Lammas) in August, when it is thought Silbury was founded, celebrates the first fruits of the harvest. It has been pointed out that the spring which rises five hundred yards south of the hill and is the source of the River Kennet, was formerly called the Cunnit, a name which may be connected to the Mother Goddess and fertility.
Another explanation argues that Silbury Hill could have been used as an accurate solar observatory by means of the shadows cast by the mound itself on the carefully levelled plain to the north, towards Avebury. The meridian line from Silbury runs through Avebury church which stands on a ley line running between Stonehenge and the stone circle at Winterbourne Abbas. The same ley line also passes through two churches and the eastern slope of Silbury. Silbury, in fact, is a centre for alignments of straight prehistoric tracks, resurfaced by the Romans, and of standing stones. The Roman road between Marlborough and Bath runs directly towards Silbury Hill before swerving to avoid it. This would indicate that the Roman road followed a pre-existing track or ley line.
