Recently, a ditch discovered back in March has now been identified as being part of a very rare monument type called a "henge", which was created in the late Neolithic and Bronze Age (c. 2300 BC) round the same time as Stonehenge. The ditch excavated here is up to 8m across and at least 2.5m deep, curves only very slightly and based on the small part of the plan so far recovered, would have enclosed an area of at least 150m diameter, encompassing all of what is now Keble College and the Pitt Rivers Museum.
This discovery adds considerable interest to cropmark evidence (visible from the air) in The Parks, already well known since the 1970s, showing three large circular ditches, and other features, These are usually thought to represent levelled Bronze Age round barrows (tumuli) but may be too large (40–50m across) for that interpretation; further, smaller circles more likely to be barrows surround them, in The Parks, the University Science Area and Sackler Street. Several of these have been partially excavated in recent times. If the ditch in Blackhall Road is indeed a henge, this points to an even more significant ritual focus in this area.
About halfway up the fill in the ditch was a turfline, showing that the ditch had settled, partly filled, long enough for grass to grow. On this was set a hearth associated with Late Neolithic/Early Bronze Age Beaker pottery. To this date three deer antlers have been found in the lower ditch. These had been used as picks during the digging of the ditch and discarded (or reverentially offered to the earth they had just transformed) once it was finished. Both the hearth and the antler will be able to be dated by radiocarbon analysis which should give an accurate date for construction and use of the monument.
This is the same site that produced medieval occupation and the mass grave, thought to date to around AD1000, but these are totally unrelated to the prehistoric ditch. Click here to see the news article about the mass grave.