【摘要】 本文报道了采自贵州沿河土地坳下奥陶统的牙形石，计有２５属３９种，根据牙形石组合特征分析，认为其与黔北其它地区下奥陶统牙形石组合面貌基本一致，属北大西洋牙形石动物地理区。更多还原

【Abstract】 The section under study is situated at Tudi’ao,Yanhe County,Guizhou Province,with more than 677 identifiable Lower Ordovician conodont specimens recovered from 67 samples. Based on features and distribution of these conedont faunas,five conodont zones are established in ascending order as follows: Cordylodus angulatus Zone,Glyptoronus quadraplicatus Zone,Tripodus proteus Zone, Serratognathus diversus Zone and Oepikodus evea Zone. Table 1 shows correlations of the conedont zones with those in other areas of Europe,North America, Iran and Australia.更多还原