A series of megalithic chamber tombs in southwestern Scotland and northern Ireland with some radiocarbon dates before 3000 BC, an early stage of the Neolithic. They are sometimes described as segmented gallery graves, since they have subdivided rectangular chambers. Another important characteristic was a concave or semicircular forecourt. In some of the Irish examples, this was oval or circular and they are described as court cairns. The overlying cairns are long and either oval, rectangular, or trapezoidal in shape. Collective inhumation was the normal practice, although cremation sometimes occurred in Ireland.