In the eastern side chamber of Bacon Hole, a cave cut into the limestone cliffs of the Gower Peninsula in south Wales, there is a panel of parallel horizontal lines drawn in red pigment. There are ten of them, perhaps more, arranged with deliberate regularity across the rear wall. They have been there for roughly 17,100 years.
That last sentence contains more uncertainty than it looks. The lines were first noticed in 1912, declared the earliest cave art in Britain, then reclassified as a natural mineral seep, then more or less forgotten for nearly a century. Only now, following two campaigns of uranium-thorium dating and detailed archaeometric analysis,1 has a team led by George Nash of the University of Liverpool and the Geosciences Centre at Coimbra confirmed what William Sollas and Henri Breuil claimed in the first place. The marks are haematite, applied by human hands, and the calcite flowstone sealing them from above dates to approximately 17,000 years before present.
If the dating holds, Bacon Hole is now the oldest-dated rock art in Britain and northwestern Europe.
