Rock Slab Found in 1900 Now Hailed as 'Treasure Map'

There's no bright red "X" marking the spot where treasure can be found. Still, archaeologists believe they've found a "treasure map" in the form of a 4,000-year-old rock slab whose engraved markings match natural features in France's westernmost Brittany region. The large stone, known as the Saint-Bélec slab, was discovered in 1900 in the lining of an ancient burial mound in what is now the city of Roudouallec. Paul du Châtellier, the archaeologist behind the discovery, made note of the lines and shapes engraved on the surface, but it took more than a century for researchers to discover what they meant. After creating a 3D scan of the slab, they noticed certain markings matched Roudouallec's mountains and rivers with 80% accuracy, per Insider.

Those findings were published in 2021. Since then, archaeologists have been working to uncover more of the slab's secrets. They spent the past few weeks digging at the burial mound in hopes of finding a precise date for the artifact, thought to have been carved between 2150 BC and 1600 BC. In the process, they uncovered additional fragments of the slab, which had apparently been broken off, per Insider. Researchers now believe cup shapes and tiny hollows in the slab's surface could mark the locations of mineral deposits or Bronze Age burial mounds, perhaps even the burial mound of the slab's original owner, AFP reports.

According to France's National Archaeology Museum, which received the slab after du Châtellier's death, the map might have been used by a ruling prince, who was likely buried with prized objects of bronze and perhaps gold. That makes this "a treasure map," lead researcher Yvan Pailler of the University of Western Brittany tells AFP. Though archaeologists typically rely on radar and aerial photography to identify ancient sites, "using the map to try to find archaeological sites is a great approach," he adds. However, the map reflects an area that measures nearly 250 square miles, and Pailler's colleague, Clement Nicolas of Bournemouth University, says surveying it all could take 15 years. (More discoveries stories.)