NEW research suggests that the famous Preseli bluestones used in the construction of Stonehenge could have been carried or dragged overland – and not transported by sea – and were originally part of an ancient stone circle in Wales.

The intriguing new evidence published in the journal Antiquity argues that the location of the two ancient quarries at Carn Goedog and Craig Rhos-y-felin suggests the two-ton blocks, up to 80 in number, were dragged or carried over land.

The archaeologists’ research also puts forward the possibility that the stones may have first been used in a stone circle in Wales, before that monument was dismantled and moved to Salisbury Plain.

Professor Mike Parker Pearson of University College London, who led the excavations, said: “What’s really exciting about these discoveries is that they take us a step closer to unlocking Stonehenge’s greatest mystery – why its stones came from so far away.

“Every other neolithic monument in Europe was built of megaliths brought from no more than 10 miles away. We’re now looking to find out just what was so special about the Preseli hills 5,000 years ago, and whether there were any important stone circles here, built before the bluestones were moved to Stonehenge.”

The latest dig focused on Carn Goedog, where Parker Pearson and his team was able to identify recesses in the rock face from which pillars were quarried, carbon-dating charcoal found between the slabs to the fourth millennium BC.

They also discovered a number of distinctively wedge-shaped stone tools which they believe were hammered between the slabs in order to prise them apart, and identified V-shaped gaps between the pillars that they think were cut into the rock to place the wedges in.

The work has also uncovered what is thought to be an artificial platform at the base of the outcrop, laid with stones where the bluestone pillars could be eased down and which then acted as a loading bay for lowering them on to wooden sledges before the stones were dragged away.

The bluestones were previously thought to originate from the southern Preseli hills, but the location of Carn Goedog and the other confirmed quarry on the northern slopes of the range “completely changes” the assumptions of how the stones were transported to Stonehenge, added Dr Rob Ixer, one of the co-authors of the report.

It had been thought they were dragged down the southern slopes to Milford Haven, and then transported by raft along the Severn estuary and the River Avon to Salisbury plain. It is now argued the stones were all manually transported across land.

But as to the question of why the stones were transported, it will probably never fully be answered.

“We will never understand Stonehenge. That is the beauty of the monument,” said Dr Ixer.