ash, tools, weapons and ornaments have been dug up from such mounds, many of which contain kistvaens or chambers of stone. The lynchets or terraces which score some of the hillsides are said to be the work of primitive early farmers and agriculturists. Ancient strongholds are scattered over the county. Among the most remarkable are Vespasian's Camp, near Amesbury; Silbury Hill, the largest artificial mound in Europe, near Avebury; the mounds of Marlborough and Old Sarum; the "camps" of Battlesbury and Scratchbury, near Warminster; Yarnbury, to the north of Wylye, in good preservation; Casterley, on a ridgeway near Devizes; White Sheet hill; Chisbury, near Savernake; Sidbury, near Ludgershall; and Figsbury Ring, northeast of Salisbury. Ogbury, ten kilometres (6 mi) north of Salisbury, is an undoubted British enclosure. Durrington Walls, north of Amesbury, are probably the remains of a British village, and there are vestiges of others on Salisbury Plain and the Marlborough Downs. Roman remains There are many signs of Roman rule. Wansdyke or Wodens Dyke, one of the largest extant entrenchments, runs west for about from a point east of Savernake, nearly as far as the Bristol Channel, and is almost unaltered for several kilometres along the Marlborough Downs. Its date is uncertain; but the work has been proved, wherever excavated, to be Roman or Romano-British. It consists of a bank, with a trench on the north side, and was clearly meant for defence, not as a boundary. Forts strengthened it at intervals. Bokerley Dyke, which forms a part of the boundary between Wiltshire and Dorset, is the largest among several similar entrenchments, and has also a ditch north of the rampart. Recent excavations In April 2022, metal dedectorists announced the discovery of two 4.000 years-old Bronze Age axe heads on land owned by a farmer. The remains are being stored in Bristol Museum. Architecture Ecclesiastical buildings Monastic houses Chief among the few monastic buildings of which any vestiges remain are the ruined abbeys of Malmesbury (still in use as the parish church) and of Lacock. Amesbury's Church of St Mary and St Melor may have been linked to the 10th-century Amesbury Priory or its 12th-century successor, Amesbury Abbey. Monkton Farleigh had its Cluniac priory, founded as a cell of Lewes in the 13th century, and represented by some outbuildings of the manor house. A college for a dean and 12 prebendaries, afterwards a monastery of Bonhommes, was founded