The Y-Z Holes...

The two rings of holes around Stonehenge are known as the Y - Z holes, and once had stones in them. Looking down on the site, one would have seen three rings of stones. The distance from the Y holes to the Sarsen Circle is a third of the Sarsen circle diameter. The Z holes are a third of that distance, again measured from the Sarsen circle. The stones in the Y - Z holes provided a strong base and acted as anchor points for the thirty large wooden buttresses.

All the outward pressure from the weight of the roof would be transmitted down the buttresses, directly into the ground via the Y stones, which also ensured that the buttresses and timber supports were kept off the ground, avoiding any possibility of damp.

Existing Holes at Stonehenge

The buttresses formed a frame, locking the Sarsen Circle together with tremendous strength and stability. To connect the buttresses together and make the frames, a ring of cross members was used. These cross members were directly above the upright wooden supports, one third of the distance along the buttresses and measured to be two thirds of the height of the Sarsen circle.

So where are they now? The stone footings which once filled the Y-Z holes were removed centuries ago. A farmer told Bruce Bedlam that to remove a stone of this size, you light a fire at one side and the stone will crumble and is then easily removed. One of the mysteries of the Stonehenge site is that so many of the Y-Z holes have had fires in them at one side.