含双壳类：Tetoria yixianensis，T. fuxinensis，Corbicula（Mesocorbicula） tetoriensis，Ferganoconcha subcentralis，Sphaerium jeholene，Nakamuranaia chingshanensis，Sphaerium selenginense，S. pujiangense，S. subovatum，Ferganoconcha sibirica，N akamuranaia elongata；植物：Coniopteris onychioides，Ruffordia goepperti，Brachyphyllum japponicum，Ginkgoites sibiricum；腹足类：Viviparus sp.，Probaicalia gerassimovi；介形虫 Ziziphocypris costata。介形虫 Cypridea unicosta，C.vitimensis；轮藻：Clypeator jiuquanensis，Flabellochara harrisi，F.liangdanensis，Atopochara trivolvis，Triclyeloa jianluoensis 等。为湖相、沼泽相沉积。底与周家湾组整合接触，或直接覆盖在前侏罗纪地层之上；其上被第三纪甘肃群不整合覆盖。厚334-1200米。