Seven Stones reef

The Seven Stones reef is a rocky reef nearly 15 miles (24 km) west-north-west (WNW) of Land's End, Cornwall and 7 miles (11 km) east-north-east (ENE) of Isles of Scilly. The reef consists of two groups of rocks and is nearly 2 miles (3.2 km) long and 1 mile (1.6 km) in breadth. They rise out of deep water and are a navigational hazard for shipping with 71 named wrecks and an estimated 200 shipwrecks overall. The most infamous is the Torrey Canyon in 1967, which was at that time the world's costliest shipping disaster, and to date, still the worst oil spill on the coast of the United Kingdom. The Sevenstones lightvessel has been situated to the east of the reef since 1841, to warn ships of the danger and to mark the western boundary of a major north/south shipping route between the Isles of Scilly and the Cornish coast. An automatic weather station is on the lightvessel.

Situated between Cornwall and the Isles of Scilly, the Seven Stones reef consists of seven (or eight) peaks, some of which appear at half ebb and others at low tide. They rise out of deep water, at 60 fathoms (110 m) and extend nearly two miles from north-north-west (NNW) to south-south-east (SSE) and are about a mile wide. The sea always breaks over the reef and in good weather, breakers are visible up to 12 miles (19 km) away. The rocks consists of small-grained granite which is part of the larger Cornubian batholith. The batholith formed during the early Permian period, from about 300 to 275 Ma, at a late stage in the Variscan orogeny. Some of the stones have been given names and include Flat Ledge, Flemish Ledges, North-east Rocks, Pollard's Rock, South Rock and a ledge known as the Town.

During the 1960s the reef was fished by a small fleet of French fishing vessels for crab, crayfish and lobster. Some of these vessels were the first on the scene when the Torrey Canyon sank in 1967. On the vertical surfaces there are clusters of jewel anemones and hydroids, and plumose anemones on the more exposed rocks.

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