There are two different stones found at Stonehenge. Both of which have been said to be found in other areas of the British Isles.
The smaller stones used at the site are a type of stone called, bluestone. There are 82 bluestones found at Stonehenge each of which measures eight feet tall and weighs around 4 tons a piece. There are many different variations of bluestone and four of these variations have been collected at Stonehenge.
As for the larger stones, these are known as sarsens. These sarsen stones have been described as huge rocks that have a density harder than granite.
These stones have been researched and were said to have formed on the seabed and then broken apart when the seabed raised up to level with the land. They broke apart in huge boulder sized pieces which explains the sarsens immense size.
The sarsens at Stonehenge weigh around 26 tons, with the largest sarsen weighing around 45 tons. Sarsens are the large vertical stones that stand at 13 and a half feet tall and are as thick as 7 feet. On top of these large stones are smaller stones called lentils that lie across the tops of two sarsens horizontally. Although these stones aren’t as large they are still several tons in weight.
How these stones got to Stonehenge is still a cause for debate as the bluestones came from much farther away than did the sarsens.
Scientists have come up with several theories on how the stones were transported from such great distances. It is estimated that it would have taken sixteen men per ton of stone to move them to Stonehenge. There is no evidence that these stones were moved and then immediately constructed. They could have been piled up and saved for future use. They would have had to use waterways where they were pinned between two hollow canoes or on rafts that were crafted from wither wood or animal skins. Since they used mainly waterways to transport these rocks they would have only been able to move them in the summer when the water was calm and the weather suitable for hard labor.
There is also a possibility that the stones were deposited by stonehenge from an ice that occurred about a half a million years ago. The stones could also have been slid over ice sheets and transported to Salisbury.