The central stone has what are thought to be cup marks. It is supposed that the stones were dragged to the site on logs and levered into position, probably either for seasonal information or for use at religious ceremonies. Houlder (1978) speculates that they were once part of a much larger and impressive alignment, but Castleden (1992) suggests that they did not form part of a stone circle  Aubrey Burl asserts that short stone-rows of this kind were used as the ritual centres of families of "perhaps ten or twenty adults and children", though the erection of large stones required the co-operation of several such families. He compared the Trellech stones to the row at Le Vieux-Moulin, Plouharnel, near Carnac, and says that "Similar short rows were erected by communities in Ireland, Britain and Brittany in the centuries of the Bronze age between 1800 and 1000 BC". The source of the Trellech stones may have been the nearby Beacon Hill where there are outcrops of a similar conglomerate. A fourth stone, on nearby common land, is believed to have been destroyed in the 18th century. Tump Terret is situated within the grounds of Court Farm to the south-west of the church. It dates back to Norman times, as the site of a small motte and bailey castle; traces of its surrounding ditch remain. The castle was still extant in 1263, when it was mentioned in manorial documents. A local myth, commemorated on the sundial, was that it was a burial mound for those killed in actions between the forces of Harold Godwinson and the opposing Welsh. A now-vanished summer house was built by the Rumsey family on top of the mound. Trellech Court - now the site of the farmhouse - was the seat of a branch of the Seymour family until it passed to John Rumsey in the early 18th century. The existing building is, according to Bradney, "a building of no architectural features", and dates from around the time of Rumsey's ownership. It was converted into a farmhouse in the later 19th century. Sometimes known as St Anne's Well, this circular wellspring, surrounded by a stone wall and seating, is located in a field on the left of the road to Tintern, about east of the village. Local tradition is that it is the only one remaining of originally nine holy wells in Trellech. In the 17th century, it was reportedly much frequented, and reputed to cure "the scurvy, colic and other distempers".