GRAFHEUVELS OP DE ONSTWEDDERHOLTE (GEM. STADSKANAAL, GR.)
In the province of Groningen with its vast Holocene peat and clay deposits, prehistoric burial mounds are a rare phenomenon. The few mounds known were excavated during the reclamation boom in the first half of this century and thus disappeared. Aerial photographs, however, have brought to light unknown sites of completely levelled burial mounds. A group of three is situated on an ice-pushed ridge near Onstwedde, in the eastern part of the province. Excavations there took place in 1986 and 1990. They were found to be of Middle Bronze Age date, each with a different peripheral structure and built on former settlement ground from the Beaker period. Two of them are thought to have been erected as early as the Late Neolithic. The 1990 excavation of two of the monuments is discussed here. As to the whole group of three, there are plans to restore them to their Middle Bronze Age appearance.