Page "Stonehenge" Paragraph 22

During the next major phase of activity, 30 enormous Oligocene-Miocene sarsen stones ( shown grey on the plan ) were brought to the site.

They may have come from a quarry, around north of Stonehenge on the Marlborough Downs, or they may have been collected from a " litter " of sarsens on the chalk downs, closer to hand.

The stones were dressed and fashioned with mortise and tenon joints before 30 were erected as a diameter circle of standing stones, with a ring of 30 lintel stones resting on top.

The lintels were fitted to one another using another woodworking method, the tongue and groove joint.

Each standing stone was around high, wide and weighed around 25 tons.

Each had clearly been worked with the final visual effect in mind ; the orthostats widen slightly towards the top in order that their perspective remains constant when viewed from the ground, while the lintel stones curve slightly to continue the circular appearance of the earlier monument.

The inward-facing surfaces of the stones are smoother and more finely worked than the outer surfaces.

The average thickness of the stones is and the average distance between them is.

A total of 75 stones would have been needed to complete the circle ( 60 stones ) and the trilithon horseshoe ( 15 stones ).

Unless some of the sarsens have since been removed from the site, the ring appears to have been left incomplete.

The lintel stones are each around, wide and thick.

The tops of the lintels are above the ground.