Four sarsen stones at Stonehenge placed inside the internal bank of the henge, roughly on the line of the Aubrey Holes (see SU 14 SW 4 for Stonehenge). Two, known as the North Barrow and South Barrow, are surrounded by circular ditches, which gave rise to suggestions that they might have been round barrows. As a result, the have been listed by Grinsell as Amesbury 12 and 13, a possible saucer barrow and possible bowl barrow respectively. They are not barrows. Both now lack their stones. The North Barrow has seen excavation, confirming the presence of the stone hole. The other two unenclosed Station Stones still feature their sarsens, one upright and one fallen. The four sarsen Station Stones are assigned to Phase 3a in Cleal et al's (1995) new phasing of Stonehenge. The ditches around the two "barrows" are assigned to Phase 3b, the date in each case being broadly Late Neolithic or Early Bronze Age.