Coal the heat and pressure of deep burial causes the loss of water, methane and carbon dioxide and an increase in the proportion of carbon. Thus first lignite (also called "brown coal"), then sub-bituminous coal, bituminous coal, and lastly anthracite (also called "hard coal" or "black coal") may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to
Gráinne (given name) Gráinne (given name) Gráinne is a feminine given name in the Irish language. The name is of an uncertain origin, although it is possible that it may be connected with the word "Ghrian", meaning "the Sun". In Irish legend, Deorghrianne (a Tear of the Sun), is the daughter of Fiachna, Son of Betach. The name is also borne by a famed character in Irish mythology—Gráinne, who was the daughter of Cormac mac Airt, a legendary High King of Ireland. The name can be Latinised as "Grania"; and can be Anglicised as "Granya". The name "Gráinne" can also be represented in