Alarge number of coral fossils such as Arachnastraea, Chaetetes and Mulithecopora have been found in the marine strata of the upper part of the Carboniferous Benxi Formation in the eastern part of North China. The coral fossils are so abundant that they form coral limestones in some outcrops. These limestiones almost made up a rock belt, in which coral reefs are formed in some sections [1]. The occurrrence of the belt provides improtant information for understanding of the history of the Middle and Late Carboniferous in the eastern part of North China.