Fields of treasure

THEY are fields like any others - flat, stubbled with the promising green shoots of winter cereal as the November sun slants over the Yorkshire Wolds to the south, lighting a distant hillock to golden fire. Dominic Powlesland gestures with a long, lean arm, pointing into the sun. Over there is the Anglo-Saxon village, he says. That hump lit by the sun is a Bronze Age mound.

To me, still, they look just like fields. But that's because everything that's archaeologically interesting about these 3,000 acres of farmland sandwiched between The Wolds and the North York Moors is underground.

Archaeologists working at this site near West Heslerton, which has been likened in importance to Stonehenge or Avebury, have discovered a buried landscape of farmsteads, villages, paths and fields dating back 6,000 years that is transforming our understanding of the way our remote ancestors lived.

Beneath my feet, much of it preserved simply in minute variations in the magnetic alignment of the soil, are the remnants of Bronze Age henges and trading routes; Iron Age farms and roads; Roman houses; and Anglo-Saxon villages.

Now they are being mapped using a combination of aerial photography and hi-tech magnetic sensors. Archaeologists say they prove that ancient Britain was much more heavily populated and intensively farmed than we ever realised.

Among their finds is an Iron Age 'linear settlement' strung out west to east across the Vale Of Pickering. Although 2,500 years old, it was a busy road, with a big farmstead every 250 metres or so, and a latticework of fields all around - just like an ancient A64, in fact.

"It was a perfect ribbon development," says Dominic, gesturing across the fields in the direction the ancient road would have taken. "And if you've got settlements of big farms every 250 metres, it is not that different from the development (on the A64) today."

Even 2,500 years ago, this was a crowded landscape - with very little land left uncultivated. And if that was the case at West Heslerton, it probably would have been elsewhere in lowland Britain. "There would have been a late Iron Age population of millions, not hundreds of thousands," says Dominic.

What makes West Heslerton unique is not this history of continuous occupation and cultivation stretching back millennia - if the archaeologists are right, much of lowland Britain has such a history - but the fact that, perhaps for the first time on this scale anywhere in the world, archaeologists have been able to map it in the way they are.

There are two main reasons for this. The first is the sands, which for thousands of years have been blowing across the land from nearby wetlands, covering and protecting the remains of ancient buildings and roads.

The second is the sheer length of time archaeologists have been working here. Dominic, director of the Landscape Research Centre based at nearby Yedingham, has been at West Heslerton for 25 years.

That continuity has enabled him and other archaeologists to develop a true feel for the hidden history of the area.

For much of that time, archaeologists were working on what Dominic describes as 'rescue' excavations - emergency digs on sites at risk of being damaged by quarrying or intensive agriculture.

Aerial photography makes it possible to spot the outline of ancient workings invisible to those standing on the ground because crops grow differently on soil that has been disturbed. This has helped to build up a more complete picture of the area's archaeology.

In the past few years they have been able to call on the latest technology - magnetic sensors able to detect tiny variations in the magnetic alignment of the soil underground.

This enables archaeologists to magnetically 'map' ancient features such as building foundations, ditches, burial sites and field boundaries.

Disturbances in the soil when these were originally made by our ancestors caused a tiny variation in the magnetic alignment of iron in the soil which can still be detected today.

Archaeologists with the Heslerton Parish project have spent the past two years or so walking every foot of the 3,000-acre site taking magnetic readings. "They have done immense work," says Dominic. "They have walked thousands of miles, taking a reading every 25 cms."

Using the combined results of these readings and aerial photography, they are now making what is effectively a 3-D 'time map' of the site, from the earliest Neolithic times through to the Anglo-Saxon and medieval periods.

They have made some surprising discoveries such as the fact that as early as the late Bronze Age 3,000 years ago much of the Vale Of Pickering had already been parcelled up into large 'estates'. This offers evidence that Bronze Age farmers were part of a sophisticated society.

They have also discovered a Bronze Age road - what Dominic describes as a 'green lane' - running east/ west across the site. It was bordered with banks and ditches and would have been a major trading route to the coast. Although unpaved, archaeologists know it would have been used by wheeled vehicles such as carts. "We have excavated one, and found the wheel ruts," he says.

The Heslerton Parish project has also revealed other interesting finds - such as that the Dark Ages never happened.

Farming continued virtually unchanged in the Vale Of Pickering when the Romans left in about 400AD, Dominic says - and the coming of the Anglo-Saxons may even have marked something of a Brave New World'.

All fascinating findings.

But the Heslerton Parish project has a greater aim.

The biggest threat to archaeology of this kind lies in agriculture and mineral extraction.

Both could threaten the archaeology of West Heslerton - but for the fact that the detailed maps Dominic and his team are producing will enable them to draw up strategies for preserving the archaeology, while allowing farmers and mineral companies to continue to earn their livelihoods.

When it comes to agriculture, for example, certain crops are more of a threat than others.

Potatoes are quite invasive, cereals cause little damage.

With the help of the maps, this could be used to the archaeologists' advantage.

There are large areas of the site where there is no interesting archaeology at all, Dominic explains. "And the most crucial, important areas may be only 150 yards wide."

Plant potatoes where there is no archaeology, and cereals where there is, he suggests, and there is no reason why modern farming need pose a threat.

He has already been in talks with farmers and landowners for about a year, he says, and has found them very co-operative.

"No farmer or quarry operator wants to wake up one morning and discover they have terribly damaged a major archaeological site," he says. "At least, I have never met one. We had one farmer saying he had no idea any of this was here, and that he will not put potatoes on it."

So, hopefully, we can all continue to go about our 21st century lives while this hidden history lives on undisturbed beneath our feet.

Updated: 09:53 Friday, November 21, 2003