Although the site today lacks the encircling ditch
and bank, excavation has shown that this used to
be a henge monument, possibly the oldest in the
British Isles.  The stones are thin slabs, approximately
300mm thick with sharply angled tops.  Four, up to
about 5m high, were originally elements of a stone
circle of up to 12 stones, laid out in an ellipse about
32m diameter on a levelled platform of 44m
diameter surrounded by a ditch.