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
A Star Is Burns but Marge and Jay convince him to reconsider and "Pukahontas" is named the winner. Barney declares that his victory has inspired him to give up drinking, but immediately forgets his promise when Quimby reveals his prize to be a lifetime supply of Duff Beer. Sherman prepares to return to New York, and the Simpsons thank him for his help in making the festival a success. Marge suggests that Mr. Burns has learned a lesson that you cannot bribe everyone. Contrary to her statement, he submits "A Burns for All Seasons" to the Academy Awards; due to his bribing of everyone