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
What a Nightmare, Charlie Brown! owner to be swallowed into the water. Snoopy finds himself being pulled into the hole. As he sinks screaming for his life, Snoopy wakes up clinging to the side of his doghouse and is relieved that he was just having a nightmare. Snoopy then wakes Charlie Brown and recounts his nightmare in pantomime, to which Charlie Brown allows Snoopy to spend the night inside with him, but not before Snoopy helps himself to a large ice cream sundae, reminding himself his Arctic experience was indeed a nightmare. What a Nightmare, Charlie Brown! What a Nightmare, Charlie Brown! is the 17th