Bishops and Clerks
The Bishops and Clerks are a group of rocks and islets situated in St George's Channel 1 to 2 miles west of Ramsey Island, Pembrokeshire, Wales.
There are four distinct groups of islets. From the north these are:
In addition, the three small wave-washed rocks of Carreg-trai, Llechau-isaf and Llechau-uchaf sit in the waters between the Bishops and Clerks and Ramsey Island and the Welsh mainland.
The South Bishop Lighthouse is built upon Emsger or South Bishop. Thirteen or so shipwrecks are recorded in the waters immediately surrounding the islands, notably North Bishop.
The two northerly islet groups are formed from gabbro, a hard-wearing rock of igneous origin whilst those of the Daufraich group to their south (and indeed Llechau-isaf) are formed from microtonalite, another intrusive igneous rock. The most southerly, Emsger is formed from rhyolite. All these are of probable lower Palaeozoic origin. Llechau-uchaf is formed from the late Cambrian 'Lingula Flags' whilst Carreg-trai is formed from Ordovician acid tuffs of the Llanrian Volcanic Formation. The submarine geology between the main groups is formed by sandstones and mudstones of Cambro-Ordovician age, though the bedrock is partly covered by sand and gravel.
Coordinates: 51°52′12″N 5°23′42″W / 51.87°N 5.395°W
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