下扬子区大隆组的底界

<正> 下扬子区大隆组化石丰富、牙形刺动物群以 Neogondolella subcarinata-N.chang-xingensis组合为特征,与长兴组一致;而菊石动物群既有长兴阶的Pseudotirolites,Ple-uronodoceras,Tapashanites分子,又有吴家坪阶的 Anderssonceras,Konglingites分子。郭佩霞同志协助笔者对江苏南京湖山、团山、安徽铜陵杨桃山、南陵丫山、泾县晏公

The basal limit of the Dalong Formation in the Lower Yangzi region

The Dalong bormation is a lithostratigraphie unit composed of marine facics sediments of gray Mack siliceous rocks, siliceous mudstones and shales intercalated with limesiones.In the last ten-odd years, sonic scholars suggested [hat the siliceous rocks should be divided into two pans, those containing ammonites Anderssonoccrai and Kanglingites should be referred to the Longtang Formation and the Da-long Formation should be limited to the horizon yielding late Late Permian ammonites" Based on the longitudinal and horizontal distributions of conodonts in the Lower Yangzi region, the Da long Formal ion should use the basal surface of the "Yamei Limestone" or "Xiayao Limestone" as its basal limit, and the basal surface of the yellow green argillaceous ocks containing ammonite Ophterras as its top limit.The conodonis arc marked hy Neogondolella subcartnata-N changxingnsis assemblage zone (including the Neogondolellu subcarinata-N.bitteri-N.leveni suhassemblage in the basal part and the Neogondolel-la changxingensis-N, wangi subasscmhlage in the upper part.The fusulinids are marked by Palacoju-sulina minima, P nana, Reichdina changxingensis