This tomb is probably the most interesting to look at. It is 8m across with a kerb on the east, south and west sides made with 1.2m x 1m slabs with rounded corners. The passage is 3m long and faces towards the southwest. It is possible that the passage was cruciform, but it is more likely to have been undifferentiated.
Lying in front of the passage entrance is a large limestone slab that presumably formed the door. This has a large slot in it which could have performed a similar function to the famous lightbox at Newgrange.
This monument is the northernmost of the 3 tombs on the hill and is practically on the edge of the plateau. As I climbed up here I was confronted with the kerb and was quite taken aback. I don't know what I was expecting to find, but it wasn't something this interesting.
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.