Tools discovered at the Carn Goedog quarry indicate that prehistoric workers exploited natural cracks in the rock face.

Prehistoric tools found at a quarry that supplied raw materials for Stonehenge hint at the brawn and skill needed to extract the monument’s rocks.

Some of Stonehenge’s smaller elements have been traced to the distant Carn Goedog outcrop in Pembrokeshire. During excavations there, Mike Parker Pearson at University College London and his colleagues found pieces of mudstone and sandstone that had been shaped into triangles. Ancient stonemasons probably wedged them into cracks in the rock face and hammered them, loosening Carn Goedog’s natural pillar-shaped formations.

Large recesses in the outcrop show where pillars were wrenched away from the rock face. The team suggests that after workers pried away a pillar, they lowered it with ropes onto the artificial platform of flat stones found at the outcrop’s base. There, ropes could be repositioned and the pillar loaded onto a sled.

The date of charcoal found at the site suggests that the pillars were extracted in 3500–3000 BC, just before construction began at Stonehenge.