Archaeologists excavating the site of a huge iron factory on Exmoor believe it might have been used to help produce weapons for the Roman army.
The site will be covered over again with earth when digging has finished
Experts working at the dig near Brayford in north Devon believe what they have found is far more important than they first thought.
The factory is on such a massive scale they are wondering whether the Romans may have had a greater influence in the South West than previously believed.
It is thought a lot of the iron produced there 2,000 years ago was destined for national and even international markets to make weapons and tools.
Iron ore and charcoal was heated in furnaces to about 1,000C.
The metal was collected and the slag discarded into dumps which now form part of the landscape.
The iron may have been turned into weapons and tools
Hundreds of tons of iron was produced on the site between 100AD and 300AD - far more than was needed locally.
A remote valley seems an unlikely location for a busy factory, but its remoteness has helped to preserve it as the site has not been damaged, say experts.
Once archaeologists have finished their investigations and taken away what they need, the Roman factory will be covered up with earth again to protect it.