NEW light has been shed on an archaeological riddle uncovered in the wake of a moorland blaze.

The fire, on Fylingdales Moor, in North Yorkshire, in 2003 destroyed vegetation and revealed the remains of a previously unknown ancient monument

In particular, the discovery of a 5,000-year-old stone, carved with a geometric pattern, drew international interest at the time.

Its interpretation and conservation became one of the focal points for a joint project to re-seed the ground and reinstate a protective blanket over the site, near Whitby.

New details about the find have been revealed as part of an interpretative project, Fire over Fylingdales, backed by the Heritage Lottery Fund, which includes an exhibition at Whitby Museum, open until the end of September.

The stone was set in a ring of low boulders within a larger cairn monument and included a 2ft by 2ft stone carved with cup marks and linear grooves.

The markings on the second stone are similar in design to other rock art found on Fylingdales Moor and as far away as Ilkley Moor and the Cheviots, in Northumberland.

At some point after the setting-up of the carved stones, the whole monument was covered in stones to form a cairn.

Both carved stones have been laser scanned to allow copies to be made, and left in place to preserve the complex monument.

Replicas created from the scans form part of the exhibition.

English Heritage spokesman Neil Redfern said: "There has been a vast amount of speculation on the significance of the carvings and the meaning behind the monument.

"The more decorated stone is similar to Neolithic passage grave art found in Ireland and Anglesey, perhaps suggesting a funerary purpose. But no one really knows."

The exhibition, which will open today, is accompanied by a 40-page guidebook and includes the history of more recent uses of the moor for Second World War manoeuvres, 19th Century grouse shoots and alum working.

Co-ordinator Graham Pickles said: "The exhibition is part of a wider project to tell the gripping story of the fire and the damage to the ecology, along with how the archaeology has been protected and the moor regenerated."