The dominant lithologies of the middle part are microcrystalline bioclastic limstone intcrbedded with coarse-grained dolomitic and calcareous quartzose sandstone.

• 以富含腕足化石为特色，还可见珊瑚、 、非 有孔虫、介形虫、三叶虫、苔藓虫、腹足类等生物化石。