Inishtrahull Island (Irish: Inis Trá Thall)meaning Island of the bloody beach, is located approx 10 kilometres (6 miles) north-east of Malin Head, Inishowen, County Donegal and is the most northerly island of Ireland. The most northerly landfall of Ireland is Tor Rocks located another 1km to the North West of Inishtrahull. It lies at latitude 55.43ºN.[1] Inishtrahull lighthouse Geology The island is formed from a type of the Gneiss metamorphic rock known as Inishtrahull Gneiss, dated at 1700 million years old. The gneiss is the oldest known rock on the Irish Islands, however studies have shown that the island was originally part of southern Greenland. Roddy Muir, a Scottish Geologist, in the McCallion report, argued for geological links between Greenland, Colonsay, Islay and Inishtrahull. Muir visited this area and used Plate tectonics to conclude that Inishtrahull was part of the Southern tip of Greenland c.1800 million years ago. He believes that Inishtrahull, Islay and Co
