It has long been known that the bluestones that form Stonehenge's inner horseshoe came from the Preseli hills in Pembrokeshire (Wales), around 140 miles from Salisbury Plain. Now archaeologists have discovered a series of recesses in the rocky outcrops of Carn Goedog and Craig Rhos-y-felin, to the north of those hills, that match Stonehenge's bluestones in size and shape. They have also found similar stones that the prehistoric builders extracted but left behind, and 'a loading bay' from where the huge stones could be dragged away.
     Prof Mike Parker Pearson, director of the project and professor of British later prehistory at University College London (UCL), said the finds were 'amazing'. "We have dates of around 3400 BCE for Craig Rhos-y-felin and 3200 BCE for Carn Goedog, which is intriguing because the bluestones didn't get put up at Stonehenge until around 2900 BCE" he said. "It could have taken those Neolithic stone-draggers nearly 500 years to get them to Stonehenge, but that's pretty improbable in my view. It's more likely that the stones were first used in a local monument, somewhere near the quarries, that was then dismantled and dragged off to Wiltshire."
     The dating evidence suggests that Stonehenge could be older than previously thought, Parker Pearson said. "But we think it's more likely that they were building their own monument [in Wales], that somewhere near the quarries there is the first Stonehenge and that what we're seeing at Stonehenge is a second-hand monument." There is also the possibility that the stones were taken to Salisbury Plain around 3200 BCE and that the giant sarsens - silicified sandstone found within 20 miles of the site - were added much later.      
     Speaking of the quarry in Wales, Parker Pearson said: "It's the Ikea of Neolithic monument building. The nice thing about these particular outcrops is that the rock has formed 480m years ago as pillars. So prehistoric people don't have to go in there and bash away... All they have to do is get wedges into the cracks. You wet the wedge, it swells and the stone pops off the rock."
     Prof Kate Welham, of Bournemouth University, said the ruins of a dismantled monument were likely to lie between the two megalith quarries. "We've been conducting geophysical surveys, trial excavations and aerial photographic analysis throughout the area and we think we have the most likely spot. The results are very promising. We may find something big in 2016," she said.
     Parker Pearson said people in Madagascar and other societies were known to have moved such standing stones long distances and that doing so created a spectacle that brought together communities from afar. "One of the latest theories is that Stonehenge is a monument of unification, bringing together people from across the many parts of Britain," he said.

Edited from The Guardian (7 December 2015)