The oldest coal balls were from the early end of the Namurian stage (326 to 313 mya) and discovered in Germany and former Czechoslovakia,[1] but their ages generally range from the Permian (299 to 251 mya) to the Upper Carboniferous.[48] Some coal balls from the US vary in age from the later end of the Westphalian (roughly 313 to 304 mya) to the later Stephanian (roughly 304 to 299 mya). European coal balls are generally from the early end of the Westphalian Stage.[1]