There is (working outwards) a couple of stones in the centre, then a stone circle of weathered limestone blocks, a ditch and then a bank. The stones are all as prone as Fat Mac after ten pints, but were almost certainly once standing stones. It could be a fortified position as well as whatever else. The simple fact is that we don’t know for sure about such constructions.
Nearby is Gib Hill, a burial mound which probably pre-dates Arbor Low.