Mixon Hole: The area around Selsey Bill was dry land 2000 years
ago and the site was thought to have once been the mouth of a
river. Archaeologists have traced the remains of a Roman road
which connects with the existing Chichester road as well as an old
quarry. The Mixon Hole, as the dive is called, is more like a basin
now and is geologically fairly odd. The seabed around the Mixon is 6-8m deep and much of
it dries out on a low-water spring, but the hole
descends steeply to about 26m. The top of the reef is covered in
algae and fish life, but once over the lip the rock face is barren.
Archaeologists believe that the Mixon had a Roman fort on top,
because stones in the wall appear to have been cut by human
hand. The sides are straight and the corners at right angles. And
on the bare, almost flat seabed sit several huge, rounded stones, thought by some to have
come from a catapult inside the fort - a Roman artillery piece.