There is evidence that blue stones (the term blue stone, bluestone, is used to refer to all "foreign" stones in Stonehenge) were mined in Wales 500 years before they were built in Wiltshire. This gives rise to theories designating Stonehenge as a "second-hand" monument.

It has long been known that the blue stones that make up Stonehenge's inner horseshoe come from the Preseli hills in Pembrokeshire, 140 miles from Salisbury.

Archaeologists have now discovered possible mining sites north of Carn Goedog and Craig Rhos-y-felin to match the size and shape of the stones. Similar stones were also found, which the builders extracted, but left in place as well as the place of loading, from which huge stones could be removed.

Carbonized walnut shells and charcoal from workers' hearths were examined by the radiocarbon method to find out when the stones were being mined.

Professor Mike Parker Pearson, project leader and late prehistoric professor at University College London (UCL), says the findings were "amazing."

"We have dates around 3400 BC in Craig Rhos-y-felin and 3200 BC in Carn Geodog, which is fascinating because the blue stones did not reach Stonehenge until 2900 BC," he said. "It may have taken Neolithic workers almost 500 years to get to Stonehenge, but I think that's very unlikely. It is much more likely that the stones were first used locally to build a monument somewhere near the quarry, later dismantled and taken to Wiltshire. ”According to this dating, Stonehenge could be older than originally thought, says Parker Pearson. "We think (in Wales) they created their own monument, they built the first Stonehenge somewhere near the quarries, and what we see today as Stonehenge is a second-hand monument."

There is also the possibility that the stones were placed in Salisbury around 3200 BC and that huge sandstone boulders, found 20 miles from the site, were added much later. "We don't normally make so many fantastic discoveries in our lives, but this discovery is fantastic," Pearson said.

Parker Pearson is leading a project involving specialists from UCL and the universities of Manchester, Bournemouth and Southampton. Their results are published in Antiquity magazine and in a book Stonehenge: Making Sense of a Prehistoric Mystery (Stonehenge: Solution of Prehistoric Mystery), published in the Council for British Archeology.

Professor Kate Welham of the University of Bournemouth said the ruins of the dismantled monument probably lay between two quarries for megaliths. "We did geophysical research, test excavations and photographed the whole area from the air, and we think we found the most likely place. The results are very promising. In 2016, we could find something big. "

The transport of blue stones from Wales to Stonehenge is one of the most remarkable achievements of Neolithic society. Archaeologists estimate that each of the 80 monoliths weighed less than two tons and that humans or oxen could pull them on wooden sledges sliding on wooden rails. Parker Pearson says people in Madagascar and other companies have also moved huge rocks long distances, bringing the community closer to distant communities.

"One of the latest theories is that Stonehenge is a monument to the unification of people from many parts of Britain," says Pearson.

He remembered the moment when he looked up at an almost vertical rock and realized that it had once been one of the quarries. "Three meters above us, the foundations of these monoliths were ready for someone to pick them out," he said.

"It's like prehistoric Ikea. Interestingly, these rocks formed as pillars 480 million years ago. So prehistoric people did not have to mine stones. All they had to do was get the wedges into the cracks. You soak the wedge, increase the volume and make the stone fall off the rock itself. ”