The Zitai Formation is a geological sequence of Middle Ordovician origin, that occurs along the southeastern edge of the Yangtze Platform in southern China. It is a purple-red limestone with a few interspersed yellow-green shale beds. It contains a fossil fauna dominated by trilobites and nautiloids. {{China-geologic-formation-stub}} 2 : Middle Ordovician Series|Ordovician northern paleotropical deposits |