Where did the stones come from to build Stonehenge?

Amongst the most mystical of prehistoric cultural remains, Stonehenge is located in mainland Britain and has an outer ring of eleven large dolerites called blue stones. 

The Stonehenge standing today is actually the third-final stage completed about 3,500 years ago, with the bluestones being rearranged in the form of a horseshoe as seen today. 

The Stonehenge has lost a formidable part of its stone structures that originally numbered close to sixty in the bluestone circle. In terms of construction activities, transporting the massive sized stones from their source quarry, and configuring the structure in the proper alignment would have been amongst the toughest of tasks considering the levels of zero technology in those times.  

According to the established wisdom for the past nine decades or so, the smaller rocks are probably sourced from the Preseli Hills in Pembrokeshire, Wales. The traditional theory surrounding Stonehenge dolerites and as postulated by Geologist Herbert Thomas: around five millennia ago in the Neolithic age, close to 80 bluestones were quarried and each weighed approximately three tons. 

The prehistoric culture responsible for constructing the Stonehenge must have transported the stones to the current site in Wiltshire, moving them down from the Preseli Hills by loading them on rafts to be carried on the Bristol Channel. 

Conflicting theories have emerged that discard the role of humans in transporting the stones, and account for an Ice Age glacier for transporting the bluestones to the Wiltshire region some 20,000 years ago. A more recent study published in 2014, in the Journal of Archaeological Science sheds new light on the long-running argument. 

According to a recent analysis of the Stonehenge bluestones by laser mass spectrometry techniques puts the source quarry within several kilometers from the site of construction.

The newly discovered stone quarry at Carn Goedog with a chemical composition as well as microbiology present at that time matches at least 55 percent of the spotted dolerite bluestones used at Stonehenge.