Question: What is the name of the island originating in Celtic mythology believed to lie somewhere in the Atlantic Ocean west of Ireland?
Context: Silverpit crater is a buried sub-sea structure under the North Sea off the coast of the island of Great Britain.  The 20 km crater-like form, named after the Silver Pit — a nearby sea-floor valley recognized by generations of fishermen — was discovered during the routine analysis of seismic data collected during exploration for gas in the Southern North Sea Sedimentary Basin.  Its meteor impact origin was first proposed and widely reported in 2002.  If correct, it would be the first impact crater identified in or near Great Britain.  Its age was proposed to lie somewhere in a 29-million year interval between 74 – 45 million years (Late Cretaceous – Eocene). The Fortunate Isles or Isles of the Blessed (Greek: μακάρων νῆσοι , "makárôn nêsoi") were semi-legendary islands in the Atlantic Ocean, variously treated as a simple geographical location and as a winterless earthly paradise inhabited by the heroes of Greek mythology.  The related idea of Brasil and other islands in Celtic mythology are sometimes conflated with the Greek sense of islands in the western Mediterranean: Sicily, the Aeolian Islands, the Aegadian Islands or other smaller islands of Sicily.  Later on the islands were said to lie in the Western Ocean near the encircling River Oceanus; Madeira, the Canary Islands, the Azores, Cape Verde, Bermuda, and the Lesser Antilles have sometimes been cited as possible matches. Vinotonus is a god from Celtic Mythology of which little is known.  Only seven altars dedicated to Vinotonus have been found, all of which are on the Yorkshire Moors.  As is common in Celtic Mythology, it is possible that Vinotonus was a local deity of Yorkshire.  His name may mean "God of the Vines", and it is estimated that he may have been worshipped from BCE until about 5th century CE. Pichenotte is a French Canadian tabletop game, with a board, game pieces and rules similar to carrom.  Used more broadly, the term is a general name for tabletop games played with small (usually wooden) pieces that are flicked using the thumb and index (or middle) finger, including such games as carrom, sharing a similarity in that their mechanics lie somewhere between pocket billiards and shuffleboard.  The term is sometimes also mistakenly used as the actual name of other games of this class, such as carrom and crokinole.  Commercially produced boards are available, some under the trade name Pinnochi.  The game is sometimes referred to as "piche" or "pish". Thronion (Greek: Θρόνιον ) or Thronium was an ancient Greek city of the Euboians and Lokrians in Epirus.  It is believed to lie somewhere to the south of Vlorë, between the Shushicë River and the sea. Porto Santo Island (] ) is a Portuguese island 43 km northeast of Madeira Island in the North Atlantic Ocean; it is the northernmost and easternmost island of the archipelago of Madeira, located in the Atlantic Ocean west of Europe and Africa. The effects of Hurricane Dean in the Lesser Antilles were spread over five island countries and included 3 fatalities.  Hurricane Dean of the 2007 Atlantic hurricane season formed in the Atlantic Ocean west of Cape Verde on August 14, 2007.  The National Hurricane Center's first Forecast Advisory on the system anticipated that the Cape Verde-type hurricane would pass into the Caribbean through the Lesser Antilles.  The storm moved persistently towards the small island chain, strengthening until it passed through the islands three days later on August 17 as a Category 2 hurricane on the Saffir-Simpson Hurricane Scale.  It went on to brush the island of Jamaica and reached Category 5 strength before making landfall on Mexico's Yucatán Peninsula. Celtic mythology is the mythology of Celtic polytheism, the religion of the Iron Age Celts.  Like other Iron Age Europeans, the early Celts maintained a polytheistic mythology and religious structure.  Among Celts in close contact with Ancient Rome, such as the Gauls and Celtiberians, their mythology did not survive the Roman Empire, their subsequent conversion to Christianity, and the loss of their Celtic languages.  It is mostly through contemporary Roman and Christian sources that their mythology has been preserved.  The Celtic peoples who maintained either their political or linguistic identities (such as the Gaels in Ireland and Scotland, the Welsh in Wales, and the Celtic Britons of southern Great Britain and Brittany) left vestigial remnants of their ancestral mythologies, put into written form during the Middle Ages. Feather and Bone: The Crow Chronicles is a trilogy of young adult fantasy novels written by Canadian playwright and screenwriter Clem Martini.  All of the main characters are crows, which are not so much anthropomorphic as simply animals of human intelligence who have their own culture, religion, and folktales based on Native American mythology.  While the novels take place in the "real world," elements such as the quest-like structure of the plot and the existence of a prophetic crow guided by "the Maker" lie somewhere between the realm of reality, fantasy, and the supernatural.  The trilogy is written in the first person minor point of view, with the first book from the point of view of Kalum, and the second and third from the point of view of Katakata. Brasil, also known as Hy-Brasil or several other variants, is a phantom island said to lie in the Atlantic Ocean west of Ireland.  Irish myths described it as cloaked in mist except for one day every seven years, when it became visible but still could not be reached.
Answer: Brasil