The western side of the Iapetus Ocean is in Laurentia and the other side is in the micro-continent Avalonia
About 600 million years ago , at the end of the Precambrian super-eon , the Irish landmass was divided in two , with one half on the western side of the Iapetus Ocean and the other at the eastern side , both at about the latitude that of around 80° South , close to what is now northwest Africa .
Geography of Ireland