Behind door 14, an entry to our photo competition which represents another geosite from the ‘Human Habitation’ category…
GSL staff member Maxine Smith took this beautiful photograph of the Eddystone Lighthouse while sailing out of Plymouth.
She says: ‘A round trip to the Eddystone Lighthouse is a great day sail out of Plymouth. The Lighthouse is continually visible during the sail when setting off from the Breakwater, which is about 12 miles away.
‘I’ve also scuba dived the rocks and reef many times. The shallow water near the rocks quickly gives way to deep water and a sandy bottom at about 40-50 metres, there is prolific sea life and the visibility is usually excellent.’
The Eddystone Lighthouses
The current lighthouse is located on the Eddystone rocks, which are 9 miles south of Rame Head, Cornwall, and represents a feat of engineering in terms of design and construction.
The fifth tower, built in 1882, is the one now standing, and was designed by James Douglass. Next to it are the remains of the solid base of Smeaton’s Tower, built 1759.
Smeaton’s Tower was the first lighthouse to be built using mainly stone blocks with dovetails that held the stone in one solid mass. The rest of Smeaton’s Tower now stands on Plymouth Hoe.
Before the erection of a lighthouse, the Eddystone rocks were a treacherous hazard for ships in the approaches to the English Channel and the port city of Plymouth.
The Eddystone rocks are something of a geological anomaly in South West England: they comprise garnetiferous gneissic rock and are part of considerable underwater outcrop of mica-schists and granitoid gneisses.
Isotopic ages suggest that the last period of deformation was during the end of the Devonian, but their highly metamorphosed state indicates they might be a relic of earlier tectonic activity, probably of Precambrian age.