Rock Markings Dismissed a Century Ago Are the Real Deal

A set of red stripes once written off as a geological quirk has just been restored to its place as Britain's earliest known cave art. New testing shows the painted bands inside Bacon Hole, a cave in south Wales, were created about 17,100 years ago—beating other UK examples and making them the oldest known in northwestern Europe by at least 1,500 years.

Discovered in 1912 by professors William Sollas and Henri Breuil and then-identified as a prehistoric painting, the markings were reclassified in 1928 as "red oxide mineral seeping through the rock," as a Guardian report put it at the time. An international team led by prehistoric art specialist Dr. George Nash has now reversed that call, using uranium-thorium dating and lab analysis to show the pigment is a human-made mix of calcite and clay, "intentionally created by human agency" and applied by finger in evenly spaced horizontal lines.

The researchers said the cave may have served as a shelter for hunter-fisher-gatherers, and Nash says that what we now call art was probably "a communication system," per the BBC, with the roughly 10 red bands potentially serving as "tally marks" denoting how many years the cave had been used, for instance. Their findings appear in the journal Quaternary.