Although not marked upon either the 1:50k or 1:25k OS map, the denuded mound at the northern extremity of Beacon Hill apparently represents the remains of a round barrow... according to Buckinghamshire HER:
“Late prehistoric round barrow excavated in the nineteenth century and re-used as a beacon and Second World War gun emplacement.... Length 0600 cm Width 0350 Height 0091....Excavated by B Burgess. Found bone fragments, a horse’s tooth, a lttle charcoal & coarse brown & black pottery (B1)....” HER Number: 0091000000.