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佘田桥剖面上的佘田桥阶从岩石地层学的角度可分为三组,自下而上分别为榴江组、蒸水河组、老江冲组,其中榴江组的主要特征是紫红色粉砂质泥岩/粉砂岩互层、底部黑色硅质岩为特征,除钙质结核层夹层外,其他层位不含钙质;蒸水河组实际上可分为上下两部分,下部以灰黑色及暗灰色钙质泥页岩为主,上部则以泥质灰岩、似瘤状灰岩、粉砂质泥岩为主;老江冲组以泥页岩为主,到顶部附近则出现一些泥质灰岩、似瘤状泥灰岩层。佘田桥阶大致可与弗拉斯阶对比,其顶界以无洞贝腕足类和四射珊瑚的大量消失以及小云南贝动物群的兴起为界;在佘田桥地区,以黑色薄层硅质岩层作为佘田桥阶的底部,代表了腕足类 Emanuella takwanensis 的消失及弗拉斯期竹节石的兴起。综合牙形石、菊石、浮游介形虫等资料,佘田桥剖面上榴江组大致相当于牙形石 falsiovalis 带—punctata 带,蒸水河组相当于 Lower hassi 带—Lower rhenana 带,老江冲组相当于 Upper rhenana 带—linguiformis 带。
The Shetianqiao order on the Shetianqiao profile can be divided into three groups from the perspective of lithostratigraphy, which are the Lijiang Formation, the Heishuihe Formation and the Laojianchong Formation from the bottom to the top, respectively. The main features of the Lijiang Formation are Fuchsia silt mudstone / siltstone interbedded layers, the bottom of the black silicalite is characterized by, except calcareous nodular interlayer, the other layers do not contain calcium; Steamed River Group can actually be divided into two parts up and down, the lower part Mainly limestone and dark gray calcareous shale, while the upper part is dominated by argillaceous limestone, algal limestone and silty mudstone. The Laojianchong Formation is dominated by shale and near to the top There are some argillaceous limestone, like tumor-like marl layer. Shetianqiao order can be compared with the Frastian order. The top boundary of the Shetian Bridge is bounded by the disappearance of broad-bored brachiopods and the massive disappearance of coral corals and the rise of the small Yunibei fauna. In Shetianqiao area, The siliceous rock, as the bottom of the Shetianqiao stage, represents the disappearance of the brachiopod Emanuella takwanensis and the rise of the Frasnian stemstone. Synthetical conodont, ammonite, plankton and other information, the Shetian Bridge section of the Ju River Formation roughly corresponds to the conodont falsiovalis belt-tubata zone, the same group of the lower water with the Lower hassi -Lower rhenana belt, The Jiang Chong Formation is equivalent to the Upper rhenana belt-linguiformis belt.