Solving the mystery of Stonehenge

IT WAS Herbert Henry Thomas, a British geologist, who first declared that the “foreign stones” of Stonehenge—those that did not come from the vicinity of the prehistoric monument and whose raison d’être was therefore most shrouded in mystery—had been hewed from rocky outcrops in west Wales. In 1923 he pointed to the Preseli Hills of Pembrokeshire. Nearly a century later he has been found to be nearly, but not quite, right.Thomas thought Carn Menyn the most likely source of Stonehenge’s spotted dolerite bluestones, so-called because of the pale flecks that dapple their blue-green tint, and many teams have since focused on that location. But in 2013 geologists redirected the search. By observing the molecular signatures of nine of Stonehenge’s bluestones, they found that Carn Goedog (pictured), a little more than a kilometre to the north-west of Carn Menyn, was the best match.