Archaeologist Jim Leary and his work on Wiltshire’s three giant prehistoric mounds

Written by Tony Millett.

Jim Leary has carried out archaeological research on all three of Wiltshire’s pre-historic mounds: Silbury Hill, the Marlborough Mound (whose provenance as a Neolithic mound he helped prove) and, most recently, on the Marden site in the Vale of Pewsey.

The mound at Marden, which may have been fifteen metres high, was levelled some two hundred years ago.  But during the dig they found its vital remaining fifteen centimetres.  That was exciting enough, but to find the floor of a pre-historic building was amazing. It’s quite a story.

How did Jim Leary become an archaeologist?   He told Marlborough News Online that his interest began when his family lived in Cyprus and he found bits of ancient Greek sculpture in the garden.  Then, back in England as a teenager, he used to walk the family dog near their Sussex home and pick up scores of worked flints.

A-levels in the bag, he went to Cardiff University to study archaeology under Professor Alasdair Whittle. And the professor’s specialism was the pre-history of Wessex and he had written an important book on Silbury and the West Kennet palisade enclosures.  The rest, as they say, is history – very ancient history.

Silbury Hill
Just as the new millennium began (notching up just another thousand years of Silbury’s history), a major subsidence happened at the summit.  This was the result of the failure of past excavators (in 1776, 1849 and 1968) to back-fill their tunnelling properly when they left.

It looked like a disaster waiting to happen – might Silbury collapse altogether? However the mound’s unstable state allowed English Heritage to mount another and this time very expert and technologically supported excavation into the mound.  Jim directed the fieldwork on Silbury during 2007-2008.  Dating the fragments they found inside the mound showed Silbury had been constructed between about 2450 to 2300 BC. 

Using an initial analysis of what they found inside Silbury, Jim and colleague David Field wrote The Story of Silbury Hill (published a year ago by English Heritage.)  This is a general account of the Hill’s history.  Now they are working on the academic monograph which will be a doorstop of a book – “a meaty volume, very technical, telling what happened and what we found.”

It was probably a once-in-a-century excavation: “I cannot imagine anything else happening at Silbury for a long time now. There's always going to be that air of mystery about Silbury.”

The Marlborough Mound
Fresh from his work at Silbury, Jim was asked to help on the investigation in the Marlborough Mound. Jim says “I always believed it to be a prehistoric mound.”  But then he admits that lots of people say that.

He has enormous admiration for the Marlborough Mound Trust which financed the research and for Peter Carey of the Bath architects Donald Insall Associates who manage the conservation work.  (The photo left shows the crane lifting the drill gear to the mound’s summit – October 2010 – copyright Donald Insall Associates)

Financed by a former college pupil, the trust had to dig deep into its funds.  Just drilling the two main cores through the full height of the Mound – each one just ten centimetres across – cost about £25,000.
“As the costs spiralled upwards, I thought they were going to pull out, but they stuck with it – as a really important piece of work. They were brilliant.”   He admits that as the costs rose he began to have doubts about the Mound’s age.

But carbon dating on the charcoal they found at various levels inside the mound prove it was created over a period of about eight hundred years from 2840 BC.  The theory that it was nothing older than the foundations of a Norman castle was blown away.

The Marlborough Mound is almost certainly the second highest man-made prehistoric structure in Europe, but at 83 metres wide at the base and nineteen metres high, it’s quite a bit smaller than Silbury’s 160 metres wide and 31 metres high.

The conservation programme being undertaken by the Trust will take several years to complete and not all the decisions have yet been made about the end result.  It will probably look more like its eighteenth century incarnation with a spiral path to the summit than like Silbury’s grass covering.

See Marlborough News Online news story: Challenge to local author over the future of Silbury’s ‘little sister’.

Marden Henge
It’s a bit of a secret, but west of Pewsey there is a ‘Henge’ at Marden marked on ordnance survey maps. There’s little or nothing there now (see aerial photo below – photo courtesy English Heritage) and recently little archaeological attention has been paid to it. Originally this ‘henge’ included a mound that might, at about fifteen metres in height, have been Marlborough Mound’s ‘smaller sister’.

Just what is a henge?  Confusingly, it’s not something like Stonehenge. It’s a neolithic enclosure which has a ditch inside its bank and is therefore not defensive, but more likely to be a site for rituals of some kind. The Marden henge may be one of the largest and most important in the country.

It hasn’t helped that Marden lies on Pewsey Vale’s greensand and neolithic monuments survive better on chalk – like Avebury. And because the Vale is rich farming land, the area has been well ploughed over the centuries.  It may even have had standing stones like Avebury – and these have all disappeared.

Jim Leary was directing the field work at Marden for English Heritage and he was amazed to find those fifteen centimetres of the mound had survived – in it they found an animal bone fragment that will enable accurate dating.  But another surprise was to come.

The excavations revealed a very rare find indeed: the sunken floor of a Neolithic building (pictured left – courtesy English heritage.)  Jim says of this find: “The building was the most incredible discovery.”  So incredible that it made the national newspapers.

Only a quarter of this has been excavated, but it showed a circular feature that was not an ordinary hearth.  One theory is that this was the floor of a ‘sweat lodge’ into which heated stones were carried to perform cleansing of the human body rather like a Scandinavian sauna – but this was probably for ritual purification rather than for personal hygiene.

And Jim believes the henge has a clear connection to rivers.  Marden may have had an avenue leading down to the Avon – a feature of other henges.  Could it be that rivers provided the routes inland for the people from continental Europe who were bringing their metalwork to England?

The future
Jim Leary lives in Hampshire with his wife and two daughters – one a very recent arrival.  He is employed by English Heritage, but because of the government’s cuts, they have stopped doing archaeological research.

However, Jim is a true enthusiast and is determined to go back to do more work on Marden – and the technology is there to help him and his team:

“Archaeology is no longer just a social science, it’s becoming a really hard science.  What we’re getting now is really refined dating techniques – we can identify a period of thirty years in pre-history.”

Silbury’s place on the tourist map is assured.  The Marlborough Mound may yet become a  must-see site – as and when the college can allow visitors.  “However, it is now time for Marden to step up in our collective consciousness and take its place as one of the truly great prehistoric monuments in the country.” Jim Leary is sure to be there to help Marden take that place.

At the college on Monday, September 19, Jim Leary is giving the Marlborough Mound Trust’s fifth annual lecture: “The Marlborough Mound and the other Giants of Wessex."