Today, Wiltshire has the highest concentration of prehistoric World Heritage
monuments on the planet. But why does this county in southwest England boast
such an extraordinary concentration of monumental Stone Age culture in such a
relatively small area?
New research suggests that during the Stone Age, the Wiltshire landscape looked
very different to how it does today. More than 500 square kilometres of countryside
was littered with hundreds of thousands of strange rocks, now known as sarsen
stones. This vast mass of boulders was useful from a purely constructional
viewpoint: without this resource, Stonehenge and Avebury simply couldn’t have
been built, at least not on the scale that they were. But the research is revealing that
these rocks were also important in another, much more spiritual way.
To prehistoric people, fascinated by the land from both economic and religious
perspectives, the presence of all those rocks would have been a mystery crying out
for an explanation. The boulder-strewn landscape was not only completely unlike
any other in Britain, it was also fundamentally inexplicable. The rocks bore no obvious relationship to the underlying geology. They sat strewn across grass covered fields or open woodland, often lying in groups or long procession-like lines. Beneath them was simply a layer of soil and, a few metres down, natural chalk or gravel.
Just as modern humans seek explanations for the things they see in the natural
world, so, too, did our pre-scientific and prehistoric forebears – but how did they
explain the origin of these mysterious rocks? Now, long-hidden evidence is shedding new light on the probable significance of Stonehenge and Wiltshire’s other
prehistoric World Heritage sites, suggesting that the rocks weren’t just used for
building stone circles, but had other, less obvious, and perhaps more telling, uses.
Recent excavations at Silbury, the 40-metre-high, 4,400-year-old man-made hill 26
kilometres north of Stonehenge, have shown that hundreds of sarsens were
deliberately included in the matrix of the monument, almost certainly not for purely
constructional purposes. As the sarsens were 50 per cent heavier than the chalk
rubble used as the primary building material, it would have been much more difficult
and time-consuming to haul them up the side of the hill while it was under
Sarsens were included in two specific construction phases: relatively early on, and
during the later period when the main part of the mound was constructed. During the
latter phase, the sarsens were included in discrete groups within the hill’s chalk
rubble matrix. Only 40 or so were found in the recent excavations of a small section,
so it’s likely that there were hundreds in total.
What’s more, recently re-examined photographs taken during excavations in the
1960s clearly show three more groups of sarsens in the matrix of the upper part of
the monument. Their presence and potential importance seem to have been ignored
by the excavators 40 years ago – presumably because they were looking for
evidence of structures, and scattered rocks weren’t perceived as being relevant.
Because the prehistoric builders of Silbury Hill had deliberately chosen to include
sarsens, rather than restricting themselves to the lighter chalk rubble, archaeologists
have concluded that their inclusion must have been symbolic rather then purely
functional. But what did they symbolise?
To answer that crucial question is to unlock the secrets of the Neolithic mind – and
perhaps even to gain a fuller understanding of why Stonehenge, Avebury and
Silbury Hill were built in that extraordinary boulder-strewn landscape in the first
place. But to do so, we must look at other, seemingly unrelated prehistoric
monuments – and to scholarly disciplines not normally associated with conventional
The first clues are found in the burial mounds of Britain and Ireland. In Wiltshire
itself, close to Silbury, are two elongated mounds, or long barrows, that would
normally be interpreted as burial monuments. But these two earthen structures
contain no burial chambers or human remains; instead, they seem to represent
eternal resting places for sarsen stones.
One, South Street Long Barrow, less than two kilometres west of Silbury, has
around ten small sarsen stones located where the funerary chamber and human
remains would normally be. Others are incorporated in clusters into the matrix of the
The second non-funerary mound, Beckhampton Road Long Barrow, also includes a
number of sarsens – and both monuments were deliberately built on top of natural
Elsewhere, standing stones were actually erected inside burial chambers – for
example, in Ireland at Loughcrew in Meath and Carrowkeel in Sligo, and Bryn Celli
Ddu in Anglesey, Wales, as well as in Brittany. At a great burial mound at
Fourknocks in County Meath, prehistoric people had placed an oval cross-section
cobble – probably representing a human soul – next to a human skull. Nearby, at
another burial place at Knowth, Stone Age people put egg-shaped cobbles on the
sacred space immediately outside the tomb.
This suggests that rocks, stones and boulders may have symbolised or embodied
dead ancestors or their spirits, and this theory is supported by extensive historical
evidence. This tradition has been in the folklore of Britain and Ireland for millennia,
evolving over thousands of years in several phases.
The most ancient – the pre-Christian, prehistoric phase – includes stones that were
seen as being spiritually alive. They were perceived as being able to move, speak,
drink, dance and even bleed. Indeed, according to ancient tradition, the stones of
Stonehenge itself originally danced, while two standing stones in Oxfordshire are
said to ‘walk’ down to a local river to drink.
Several standing stones in Ireland were believed to speak, scream or foretell the
future: the Stone of Destiny in Tara was said to scream in approval when the rightful
king touched it, while others functioned
as oracles. In County Cavan, the Crom Cruach stone was considered a god and was
said to be accompanied by a dozen ‘standing stone’ assistants.
Other Irish folklore describes standing stones as ancient pre-Celtic giants turned to
stone by druids, and in several other cases, natural rocks (as distinct from standing
stones) were seen as, or were associated with, prehistoric deities. Other stones
were seen as embodying or containing the souls of the dead – or even the souls of
In Wales and Ireland, ancient warriors would deposit their souls in the form of stones
before engaging in battle, collecting them later if they survived. The stones that
remained were, by definition, the souls of the fallen. Piles of stones associated with
such traditions still survive near Galway in Ireland and in Powys and Mid Glamorgan
But this anthropomorphisation of stones and rocks isn’t simply an ancient British and
Irish phenomenon, but a tradition with a worldwide distribution: humans in general
can be transformed into stones in more than 20 different cultural traditions, including
those of Lithuania, Greece, China, the Pacific islands, Greenland, Alaska and Brazil.
In India, tradition says that one can be reincarnated as a rock. In Scandinavia, rocks
are seen as petrified giants, trolls and dead humans. Icelandic folklore holds that the
dead live on inside stone.
Wiltshire’s stone monuments should now be seen as having possessed an
additional dimension, for in Neolithic times, the great stones of Stonehenge and
Avebury may have been viewed as spiritually alive – not merely as temples to the
gods or ancestors, but actually embodying those spirits and deities themselves.
Where did the sarsen stones come from?
Between 60 and 40 million years ago, silt and sand were laid down either as river borne alluvium or as marine sediments ,across parts of southern England. Then, around 35 million years ago, these layers
of sand were covered up by additional deposits and were subsequently saturated
with silica-rich groundwater.
Over time, the concentration of silica increased further – possibly as a result of
increases in acidity or the evaporation of the water in which it was dissolved. When
the water could no longer hold the silica in solution, the mineral precipitated out and
filled the pores between the grains of sand. As the precipitation continued, the silica
began to act as a mineralogical glue, sticking trillions of grains of sand together to
form a two-metre-thick layer of solid rock, known as sarsen, immediately below what
had originally been the water table.
Over the past three million years – particularly during the last ice age – water
erosion and freeze-thaw processes exposed, eroded and broke up this crust of
sarsen into millions of loose boulders that remained scattered across the landscape.
Many of these massive rocks gradually slid down valley sides, accumulating at the
bottom of the slope