摘要
本文根据三个地层剖面,对西乡地区的志留纪地层进行了较为深入的研究。将该地区的志留纪地层划分为龙马溪组和崔家沟组,且首次建立起该地区志留纪的生物地层系统——笔石分带。但龙马溪组底部的笔石带则属奥陶纪。还将西乡地区的志留系与国内外有关的几个地区的志留系进行了对比。
Based on the study of three sections, the Silurian strata of Xixiang can be divided into two formations : Lungmachi Formation and Cuijiagou Formation. The biological system -graptolite zones of Siklurian strata have been first set up at these areas. The base and top boundaries of both Lungmachi Formation and Cuijiagou Formation in the Dabashan area are different from those in the Yantze region i which indicates the existence of diachronism of these two formations. In addition, the strata of Xixiang have been correlated with those of other regions at home and abroad. The so called' disconformity' inside Lungmachi Formation is acturally a fault, which is neither the top of Lungmachi Formation nor the boundary between Lungmachi Formation and Nan-jiang Formation. So. the name of Nanjiang Formation is not suitable in this area. The name of Cuijiagou Formation may be better.
