Newgrange Orthostat R18 Orthostat R18 is a stone dating from the Neolithic, located within the passage grave (ME019-045----) at Newgrange, Brú na Bóinne, Co. Meath, Ireland. The orthostat is located on the east side of the tomb's passage. R18 is made of a soft stone and has been decorated with motifs chipped into its surface. This is in contrast to the majority of decorated stones at Newgrange, whose motifs were created by "pecking" the stone with a sharp implement like flint or quartz. Nonetheless the chevron motifs seen on this orthostat are similar to others at Newgrange.