广西恭城中奥陶世笔石地层的发现

首次报道和讨论了桂北恭城中奥陶世笔石地层。该套地层以前划归为寒武系，笔石地层的发现证实为粤陶系，层位大致相当于桂北兴安的黄隘组和升平组。笔石动物群包括对笔石、四笔石、叶笔石、瘤笔石、围笔石等，可以划分为２个笔石带：Ｄｉｄｙｍｏｇｒａｐｔｕｓ ａｂｎｏｒｍｉｓ带和Ａｍｐｌｅｘｏｇｒａｐｔｕｓ ｃｏｎｆｅｒｔｕｓ带。恭城笔石动物群的发现为华南区笔石地层的研究提供了新资料，对进一步了解该区大地构造环境、

DISCOVERY OF MIDDLE ORDOVICIAN GRAPTOLITE BEDS IN GONGCHENG, GUANGXI

Discovery of middle Ordovician graptolite beds regarded as Cambrian near Gongcheng, north of Guangxi is first be reported and discussed. Finding graptolite faunas proves early Paleozoic strata locating on the northwestern part of Gongcheng and middle Ordovician rocks in North Guangxi. Its stratigraphical position probably corresponds to the Huangai Formation and Shengping Formation of Xingan, in North Guangxi. The graptolite faunas consists of Didymograptus, Tetragraptus ,Phyllograptus, Isograptus, Tylograptus ,Holmograptus, Amplexograptus ,ect. Two graptolite zones are divided : (1) Didymograptus abnormis ;(2) Amplexograptus confertus . Discovery of middle Ordovician graptolite faunas in Gongcheng provides new materials for the study of Ordovician graptolite beds of Guangxi in South China. It has great significant in advancing knowledge of geotectonic environment , sedimentary environment and paleogeography of the region.