There are so many Irish sites which seem undocumented on the internet, it makes me wonder how many are out there hiding and could be found. But this one has a photo on the Megalithic Monuments of Ireland website, and it looks superb.
Harristown is a mile south of Rathdowney and there is a stone there with the marks of St Bridgid's knees and head on it. I was told that long ago when she was passing she knelt on the stone to pray and the marks of her knees and head remained on it.
Anyone with a headache will be cured if he kneels on this stone.
This is from the Schools Collection from the 1930s, now being transcribed at duchas.ie. The stone is outside the graveyard (which is actually a circular fort) and according to the record on the Historic Environment map, there should be a holy thorn (also Bridgid / Bridget's as well), which has or had coins hammered into its bark.