Knowth Kerbstone K42
Kerbstone K42 is one of the 127 kerbstones numbered in Professor George Eogan's record of the Knowth monument. It is located on the southern side of the great passage tomb mound.
Knowth Kerbstone K42.
The Megalithic Art of the Passage Tombs at Knowth, Co. Meath
Description of Kerbstone 42
On the main face there are two slightly curved rows, each of which is composed of eight single circles picked with a medium-sized, rounded point. There are also some dispersed pickmarks.
Excavations at Knowth Volume 7: The Megalithic Art of the Passage Tombs at Knowth, Co. Meath
The complex of passage tombs at Knowth is dated c. 3200–2900 BC, and this volume deals with one of the most significant aspects of the site. It presents a complete catalogue of the 390 recorded carved stones at Knowth, through descriptions, drawings and photographs.
Six main styles of art have been identified and these are discussed, together with the motifs and techniques employed. The Knowth carvings constitute c. 46% of all such art in Ireland, and the volume sets the Knowth art in the context of the other Irish carvings, those in western and northern Britain, and also the somewhat earlier art found on megalithic tombs in Atlantic Europe.
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Knowth Kerbstone K42.
Knowth Kerbstone number 42. 
Knowth Stone Age passage tomb
K42 forms part of the ceremonial kerb documented during decades of excavation at Brú na Bóinne by Professor George Eogan and his team. Originally 127 kerbstones encircled the monument; three are now missing. Most of the survivors bear panels of curvilinear and circular ornament. Some compositions suggest careful observation of lunar rhythms, a theme that runs through much of the art at Knowth.
Medieval texts and local folklore associate Knowth with the royal cemetery of the Boyne and with ancestral powers of the land. The concentration of labour required to build Brú na Bóinne implies strong leadership and shared belief among Neolithic communities.
Later seasons of excavation exposed nineteen smaller tombs clustered around the main mound, along with pottery, house foundations and flint tools from an earlier Neolithic phase of settlement in the area, perhaps dating to around 4000 BC.
Inside the eastern tomb, the carved granite basin in the right-hand recess is among the finest Neolithic artefacts in Ireland. The block is so massive that the chamber appears to have been constructed around the basin rather than the reverse.