MORE than 2,200 previously unknown archaeological sites have been discovered on Exmoor.

And significant new information has been added to a further 800 sites, thanks to painstaking research over the last two years.

Two archaeologists from Exmoor National Park Authority looked through more than 12,000 aerial photographs as part of the Exmoor National Mapping Programme.

The time consuming exercise was designed to help build up a more detailed picture of Exmoor's past by identifying and interpreting archaeological sites.

From prehistoric settlements to enigmatic structures from the Second World War, the project has revealed the great diversity of Exmoor's historic landscape.

The work, which has been funded by English Heritage as part of its National Mapping Programme, has created a highly detailed map of Exmoor's archaeology.

During the survey the archaeologists examined piles of aerial photographs, dating from 1946 to 2009, the vast majority of them from English Heritage's National Monuments Record.

Archaeologist Cain Hegarty who worked alongside fellow archaeologist Kathy Toms on the project, said: "It's been a painstaking survey that has produced excellent results.

"We've been surprised not only by how well some earthwork sites have survived but also by their number and extent, and this even includes sites from the early prehistoric period."

Most of the newly-discovered sites date from recent periods in Exmoor's history.

However, much older remains were also found, such as the traces of Bronze Age settlements, some 3,500 years old.

Most of the photos were looked at under a stereoscope which provided a 3D effect, enabling them to see subtle earthworks.

Mr Hegarty added: "It might be possible for people to see lumps and bumps in a field but it would be difficult to differentiate from natural features without a trained eye."

With such a huge number of photos to get through he could be forgiven for thinking he was never going to get to the end of them.

But, despite the intensive nature of the work, the stuff they discovered made it all worthwhile.

Mr Hegarty said: "(Although) obviously office based for two and a half years, we are still archaeologists and like finding things.

"This is possibly the best way of finding new sites and new monuments without actually going into the field so we still have the thrill of discovery but without the mud and rain. And it was a lot warmer."

One of the most interesting finds was a possible neolithic or Bronze Age enclosure on Little Hangman Hill, Combe Martin.

Although impossible to be completely accurate as to its age, it is similar when compared with other sites thought to be around that date on Dartmoor and Bodmin.

Mr Hegarty said: "There is an ongoing English Heritage field survey which hopes to identify the extent and any internal features of the site on Little Hangman."

There are other hilltop enclosures on Exmoor but what makes this unique is its extreme location, on the top of a steep hill, overlooking the sea.

The investigation has also enabled them to add information to Second World War sites such as a local firing range where they have been able to define its boundary.

Also discovered was a stretch of previously unknown road, that could have been built by the Romans, and a possible Roman signal station and small camp.

Mr Hegarty added: "We are hoping to get money from English Heritage to write a book based on the findings of the survey work."

Rob Wilson-North, historic environment manager, described the project as "a fundamental step forward in helping us to understand Exmoor's past."

He added: "It also shows how well preserved Exmoor's archaeology is, and how much more there is to learn about it."

The project was completed in July 2009.

* To find out more about the project and the wider National Mapping Programme visit the aerial survey web-pages at www.english-heritage.org.uk