From the late Middle Ordovician to the end of Ordovician, the cephalopods, gastropods and corals in the Erlangping trough, and the conodonts, coral, brachiopods, cephalopods as well as trilobites in the Xichuan shelf were from the North China Province.

• 在中奥陶世晚期至奥陶纪末，二郎坪海槽的腹足类、头足类和珊瑚与浙川陆棚的牙形石、珊瑚、腕足类、头足类和三叶虫均属华北生物省。