Scientists discover source of rock used in Stonehenge's first circle
"Scientists have succeeded in locating the exact source of some of the rock believed to have been used 5000 years ago to create Stonehenge's first stone circle.
By comparing fragments of stone found at and around Stonehenge with rocks in south-west Wales, they have been able to identify the original rock outcrop that some of the Stonehenge material came from."
"First of all the geologists needed to sort through thousands of tiny fragments of Pembrokeshire-originating rock found by archaeologists at and around Stonehenge over the past 70 years."
According to Atkinson, three distinct types and colours of Pembrokeshire stone were found.
The Blue stones, A single fine-grained pale green stone from Milford Haven, the Alter Stone and fragments of an entirely different grey-green stone found in various post holes, identified with a particular outcrop of the Cosheston Beds at Mill Bay on the south shore of Milford Haven, about 2.5 miles above the ferry at Pembroke Dock.