Ail na Mireann, or, as it is now called, the Cat Stone, is the greatest curiosity on Uisneach Hill. It is not on the top of the hill, but on its side. It is, perhaps, the most puzzling rock in Ireland, for it is hard to say whether it was placed in its present position by an iceberg in the glacial age, or whether it was placed there by human agency, and intended for a rude cromlech. Here is what the eminent scholar and antiquarian, John O'Donovan, says about it in his yet unpublished letters when he was on the Government Survey of Ireland in 1837:--"The huge rock on this hill of Uisneach, a part of which was split and formed into a cromlech, is now called the Cat Stone, from a supposed resemblance to a cat sitting and watching a mouse." If this stone is a cromlech, or Druid's altar, it is unlike anything of the kind found elsewhere in Ireland or other countries, for the four upright stones which usually support the flat one, are not to be seen here. The weight of this enormous mass of stone can hardly be less than twenty tons, and if it was put in its present position by human agency, it is by far the most extraordinary thing of its kind in Ireland. But a majority of those who see it think that it is merely a boulder of peculiar shape. If it is a boulder it is a very extraordinary one, and if it is a cromlech it is a more extraordinary one still. It was on Uisneach Hill, or in its immediate vicinity, that the ecclesiastical synod met in the year 1111. This great meeting is mentioned in almost all Irish annals. It was attended by fifty bishops, three hundred priests, and upwards of three thousand students, and by the nobles of the southern half of Ireland, with Muircheartach O'Briain, King of Munster, at their head. We are told that the synod was convened to regulate the manners and mode of living of both clergy and laity. It does not seem to have done much good on account of the then chaotic political state of the country, caused by almost constant wars between the aspirants for chief kingship. There are many interesting things besides the cromlech to be seen on the vast undulated summit of Uisneach. There is a hollow known as St Patrick's bed, and there are the remains of the walls of large stone buildings on the most elevated part of the hill. There is also one of the finest raths in Ireland, which must have been a place of great strength, for the embankments are still of immense height, and are overgrown with hawthorn bushes of great size. This rath, unlike the generality of such structures, is not round, but oblong. It encloses a space of nearly an acre in extent.