The plan of the passage and chambers of Cairn S are quite unique. When viewed from above they are shaped like a distorted Y, with a small chamber heding diagonally off the passage. The kerb is almost complete and the cairn material is as high as the orthostats that form the passage and chamber.
One of the kerbstones has a deeply incised cross in its upper surface and one of the orthostats is carved. The passage faces roughly northwest.
A low stone used to de-lineate the divisions of a gallery. Sill stones fill the width of the space, but do not reach the roof.
A kerb is a ring of stones placed around the perimeter of a burial mound or cairn. It basically serves the purpose of a retaining wall to keep the cairn or earth in place. Kerbs are usually associated with passage 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).
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 barrow is essentially a mound of earth over one or more burials. They are more usually to be dated to the Bronze Age. There are many forms of barrow including ring, bowl, long and bell barrows.
Ring barrows are formed by digging a circular trench or fosse around a central burial, with no mound.
Bowl barrows are formed by heaping up soil over the burial(s) from a surrounding fosse, these often have an external bank too (see Ballyremon Commons (County Wicklow)).
Bell barows are simply round mounds with no fosse or external bank.
Long barrows are rare in Ireland and are more common in southwest England. Their shape is basically ovoid rather than round (see Ballynoe (County Down))
This is an explanation of (and a bit of a disclaimer for) the coordinates I provide.
Where a GPS figure is given this is the master for all other coordinates. According to my Garmin these are quite accurate.
Where there is no GPS figure the 6 figure grid reference is master for the others. This may not be very accurate as it could have come from the OS maps and could have been read by eye. Consequently, all other cordinates are going to have inaccuracies.
The calculation of Longitude and Latitude uses an algorithm that is not 100% accurate. The long/lat figures are used as a basis for calculating the UTM & ITM coordinates. Consequently, UTM & ITM coordinates are slightly out.
UTM is a global coordinate system - Universal Transverse Mercator - that is at the core of the GPS system.
ITM is the new coordinate system - Irish Transverse Mercator - that is more accurate and more GPS friendly than the Irish Grid Reference system. This will be used on the next generation of Irish OS maps.