From the 2005 Riverside Project interim report:
The standing stone was probably erect when a 30m-diameter ring ditch with internal bank was constructed around it. There was no burial at its precise centre but a small cut near its centre contained an unusual burial of a small Food Vessel with cremated remains of a small adult (possibly female) and selected unburnt and cremated bones from a large adult (probably male). In one case, cremated bones were packed within an unburnt vertebra. Grave goods were placed against the eastern side of the grave and a small, decorated Food Vessel was placed on the centre of them. On the east side, the grave goods were covered by blocks of tabular flint, and the pot was placed on top of them. These included a perforated wild boar’s tusk, barbed-and-tanged arrowheads, flint tools, antler spatulae, a miniature ‘megalith’ carved in limestone, and a flake of transparent rock crystal. This item is highly unusual and is likely to have come some distance, perhaps from South Wales or from as far away as the Alps. Later on, a second larger, undecorated Food Vessel (not containing a cremation) was inserted into the north side of the burial. Food Vessels date to c. 2300-1900 BC and it is likely, but unproven that the stone was erected before the burial.