The great prehistoric cemetery, which has been identified with the Brugh na Boinne mentioned in the Leabhar-na-h-Uidhri and in the Book of Ballymote, is situated five miles west of Drogheda, extending thence about three miles along the northern bank of the Boyne towards Slane. Amongst the most important of the sepulchral remains are the three great tumuli of Dowth, Newgrange, and Knowth, taking them in order from east to west. Two of the tumuli certainly contain chambers, access to which is gained by a passage leading from the exterior, and the third, judging from analogy, probably is also chambered. The Boyne tumuli are recorded in the _Annals of Ulster_ to have been plundered by the Danes in A.D. 862. The chamber of the Dowth tumulus has been open since 1847; that of Newgrange since 1699, when it was first entered in modern times by Edward Lhuyd, the keeper of the Ashmolean Museum at Oxford; and that of Knowth still remains to be explored. [Illustration: Longitudinal section of Chamber and Passage of Tumulus at Newgrange, Co. Meath.] The sculptures at Newgrange are of such exceptional interest that it is desirable to give a brief description of the structure upon which they are found. The tumulus stands less than a quarter of a mile north-east of Newgrange House, the Dowth tumulus being 1¼ to the north-east, and the Knowth tumulus three-quarters of a mile to the north-west. The Newgrange tumulus is surrounded by a circle of stones originally consisting of thirty-five upright monoliths, twelve of which may still be traced. Four of the standing stones near the entrance are from 6 to 7 feet in height, but the remainder are of smaller size. Between the circle and the base of the mound is a ditch and a rampart of loose stones. The tumulus is also of loose stones, surrounded at the base by a continuous curb of great slabs of stone from 8 to 10 feet long, laid on edge, above which is a retaining wall of dry rubble 5 or 6 feet high. The tumulus is approximately circular in plan, 280 feet in diameter, and 44 feet high. The area occupied by the mound alone is at least an acre. The entrance to the passage leading to the chamber is on the S.E. side of the mound, and the passage runs in a N.W. direction. The chamber is not in the centre of the mound, but to the S.E. side of the centre. The plan of the passage and chamber is irregularly cruciform, the dimensions being as follows:—