广西南丹地区中泥盆世地层为一套沉积较厚,岩性单一,皆为黑色泥质岩的沉积,并含有较丰富的菊石、三叶虫、竹节石为主的生物群。它和邻近桂中、黔南地区同时代的沉积均不相同,代表我国泥盆纪一个新的特殊的沉积类型,可称为南丹型菊石——三叶虫相沉积。根据地质普查勘探队及科研队的研究,该区的中泥盆统可分为两组:下部为纳标组,上部为罗富组。 The Middle Devonian strata in Nandan area of ​​Guangxi are a set of thick sedimentary and single lithology, all of which are sedimentary black detritus and contain abundant ammonites, trilobites, and rhushanite-dominated biota. It is different from the sediments of the same period in the neighboring Guangxi and Qiannan areas, and represents a new special sedimentary type of Devonian in our country. It can be called the Nandan-type ammonite-trilobite deposition. According to the research of geological survey teams and research teams, the Middle Devonian can be divided into two groups: the lower part is the superscript group and the upper part is the Luo Fu Formation.