Eddystone Rocks  The Eddystone or Eddystone Rocks (), are a seaswept and heavily eroded group of rocks southwest of Rame Head in Cornwall, England, United Kingdom. Although the nearest point on the mainland to the Eddystone is in Cornwall, the rocks fall within the city limits of Plymouth, and hence within the county of Devon. For centuries the rocks have been a treacherous hazard for ships in the approaches to the English Channel and the port city of Plymouth. There have been four lighthouses on the Eddystone Rocks. Winstanley (two versions; the second however just replaced the top of the structure), Rudyard, Smeaton and finally the Douglass Lighthouse, which is the present one. When the Douglass Lighthouse was completed, the people of Plymouth, grateful for the countless lives which had been saved since the introduction of the lighthouses, paid for the dismantling of the Smeaton Lighthouse from the red rocks of Eddystone and its reassembly at Plymouth Hoe, where it is a popular tourist attraction today. The stub of the Smeaton lighthouse still remains on the rocks. A traditional sea-shanty, "The Eddystone Light", chronicles a fictional encounter between the lighthouse keeper and a mermaid. The Seekers, the Weavers, and Peter, Paul and Mary have recorded the shanty. Eddystone rock is something of an anomaly in the geology of the South West region; it is composed of garnetiferous gneissic rock which is part of a considerable underwater outcrop of mica-schists and granitoid gneisses which have not been found elsewhere in South West England. Isotopic ages suggest that the last period of deformation was during the end of the Devonian, but their highly metamorphosed state indicates they likely have an older ancestry, a relic of earlier tectonic activity, probably of Precambrian age.