嫩江階

嫩江階的底界以葉肢介Halysestheria qinggangensis的首現為標誌。階內包含四個葉肢介帶和五個介形蟲組合，下部為葉肢介Halysestheria qinggangensis帶和介形蟲Cypridea(C.)anonyma C.(C.)squalid組合及C (C )gunsulinensis組合；下中部為葉肢介Euestherites bifurcatus帶、Calestherites sertus帶和介形蟲Ilyocyprimorpha netzhaevae組合；中上部為介形蟲Ilyocyprimorpha inandita組合；上部為葉肢介Mesolimnadiopsis anguanensis帶和介形蟲Harbinia hapta Talicypridea augusta組合。階內還含二個孢粉組合，下部為Proteacidites Schizaeoisporites組合，上部為Loranthacites Elytranthe組合。同時階內還含一輪藻組合Songliaochara heilongjiangensis Charites cretacea組合。