The star attraction of the fort! In a small glade in to one side of the fort is a narrow alley way that leads to five steps. These lead down into the souterrain.
I wasn't prepared for this and had no torch and so can only relay what I saw on the photos later and the very brief glimpses obtained when the flash was going off.
Once in the narrow doorway the souterrain widens out to about 2.5m and stretches back for at least 7m. The roof is lintelled with tightly packed stone beams runing width-wise.
From what I saw it still appears to be very dry - a fine testament to the builders.
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.