A cairn is a large pile of stones, quite often (but not always) containing a burial. Sometimes they have a kerb around the base.
Most cairns are hemi-spherical (like half a football), but the piles of stones used to cover wedge tombs , court tombs and portal tombs are also called cairns. When associated with these types of monument they are not always round, but sometimes rectangular or trapezoidal.
A kerb is a ring of stones placed around the perimeter of a burial mound or cairnpassage tombs, but do occur on court tombs and wedge tombs too.
Sometimes on passage tombs the stones can bear decoration, such as at Newgrange (County Meath).
cup markspassage tombs are adorned with rock art, both inside the chamber and on the kerb.
In wedge tombs and court tombs the burial compartment is known as a gallery and collectively wedge and court tombs are called classified as 'gallery graves'. This is because the inner area is long and narrow, i.e. bascially rectangular, in plan.
In court tombs the gallery is usually divided into two or more chambers by jambssill stones, as are a few court tombs.
Two stones place either side of a gallery, opposite each other, but not touching so as to leave a gap, that are used to segment it into smaller chambers.
