more: http://www.bbc.co.uk/news/uk-wales-south-west-wales-16245746Experts say they have confirmed for the first time the precise origin of some of the rocks at Stonehenge.
It has long been suspected that rhyolites from the northern Preseli Hills helped build the monument.
But research by National Museum Wales and Leicester University has identified their source to within 70m (230ft) of Craig Rhos-y-felin, near Pont Saeson.
The museum's Dr Richard Bevin said the find would help experts work out how the stones were moved to Wiltshire.
For nine months Dr Bevins and Dr Rob Ixer of Leicester University collected and identified samples from rock outcrops in Pembrokeshire to try to find the origins of rhyolite debitage rocks that can be found at Stonehenge.