sentences:  Market crosses, many once dating to the Early Medieval period, have continued to be erected and replaced until modern times.In Pictish Scotland the cross-slab, a flat stone with a cross in relief or incised on an essentially rectangular stone, developed as a hybrid form of the Pictish stone and the high cross.The cross is normally only on one side of the stone and the remaining areas of the stone may be covered with interlace or other decoration.