IT may not be the most intricate example but history sleuths are certain they have found a piece of neolithic art in the remains of a farm wall.
Volunteers for Trees for Cotherstone were carrying out their work planting saplings to replace veteran trees lost to storms and old age when they spotted something unusual.
In a field on the outskirts of village, they came across a stone that, although was weather worn, had clear markings. On closer inspection, they came to the conclusion it was an unrecorded example of rock art.
The moors of Teesdale, especially around Cotherstone and Barningham, are littered with rocks with mysterious shapes, circles, interlocking rings and carved cups.
No one knows why they were made but some historians have suggested they were prehistoric maps, marked territory, had messages for newcomers or played a role in fire or feastings.
Jeff Lynn, from the Trees for Cotherstone group, said: “There was clearly a farm building or wall here and the stone with the markings on was probably used because of it was a good fit.
“We spotted it and suspected it might be something.” Mr Lynn is also member of the history group Teesdale Record Society, which has links to respected archeologists and sent a photo to a friend who confirmed it was a piece of rock art.