Ogham (pronounced 'oh-am') is a primitive alphabet, sometimes called the Celtic Tree Alphabet, which takes the form of linear strokes cut into stone or etched onto wood. We saw a group of Ogham stones at Dunloe, 8kms west of Killarney on the R562 near Beaufort village. The guide told us that they were important, but I didn't really catch what the importance of them was. We didn't get good pictures of them from the speeding bus.
The internet information says: Seven of the eight Ogham stones in this group were discovered in a souterrain at Coolmagort in the nineteenth century and have been set up on this site close to Dunloe Castle. The tallest stone is 8 feet high. There is also a prostrate slab taken from the grounds of nearby Kilbonane church. These stones were originally the roof of a souterrain or underground passage which collapsed at the end of the last century.
Using them as lintels in underground passages protected them from the weather so that the inscriptions can still be read. I don't know what the result will be of setting them up like this.