The overlying Heshan Formation, 150 m
in thickness, is composed of black cherty limestone of
basinal facies in the lower part and white bioclastic carbonate
of sponge reef facies in the upper part. The Late
Wuchiapingian reefal carbonates about 91 m in thickness
at the Tieqiao Section are reduced to 10 m in thickness
at the Penglaitan Section.