'First Roman fortlet' found on Anglesey using geo survey
Archaeologists have discovered a Roman fortlet on Anglesey - without even putting a spade into the ground.
The team from Bangor used geophysical surveys to outline the site at Cemlyn, which it says is the first early Roman military site to be found on the island.
The Gwynedd Archaeological Trust was first alerted to it by an aerial photographer.
It described the discovery as "exciting".
Mary Aris, an aerial photographer and historian, spotted a circular mark in crops on a low hill overlooking the Anglesey coast.
The trust secured funding from Cadw, the Welsh government's historic environment service, for further inquiry.
It used surveys which detect minute changes in the magnetic properties of soil to build-up a map of the buried remains, without even breaking ground.
David Hopewell, of Gwynedd Archaeological Trust, said the results were "unusually clear", showing the "unmistakable outline" of a Roman fortlet - a smaller version of a Roman fort.
It is thought the structure dates back to the 1st Century.
"The discovery is particularly exciting because it is the first early Roman military site to be found on the island," the trust said.
"The conquest of Anglesey was famously described two thousand years ago in lurid detail by the Roman senator and historian, Tacitus, but historians have, up until now, searched in vain for any sign of forts and roads on the island."
Mr Hopewell said fortlets are usually linked by roads, 15 to 20 miles (24 to 32 km) apart, and it is hoped, therefore, the latest find will lead to other discoveries.