陕西紫阳、岚皋地区志留系笔石生物地层非常发育,剖面出露连续,化石含量丰富,研究程度较高。其中兰多维列统特列奇阶中部Oktavites spiralis笔石带(奥氏螺旋笔石),带化石特征明显、分布广泛、演化迅速、地层对比意义较强。遗憾的是,由于对该种演化历程的缺乏,带化石的首现位置以及延限始终存在争议,不利于高分辨率笔石生物地层的研究。首先,英国学者长期以来不承认奥氏笔石属,认为其胞管形态与单笔石式胞管相同,在资料中可见,归为该属的化石分子胞管形态也差别较大;同时,关于带化石分子O.spiralis的定义也较为宽泛,资料中所描述的标本在胞管形态、盘旋方式、笔石 The Silurian penoliths in Ziyang and Langao areas of Shaanxi Province are well developed and their profiles are exposed continuously with rich fossil content and high degree of research. Among them, the Oktavites spiralis pen-stone (austenitic spiral penolith) in the central part of the Ordovician order of the Randovets has obvious fossil features, widespread distribution and rapid evolution, and the stratum contrasts strongly. Unfortunately, due to the lack of such an evolutionary process, there is always controversy over the location of first fossils with fossils and the delay, which is not conducive to the study of high-resolution petrophysical stratigraphy. First of all, the British scholars have long not recognized the Austrian penicillium that its morphology and single cell tube of the same stone tube, can be seen in the data, classified as the genus fossil morphological differences between the larger cell tube; the same time, On the definition of fossil O.spiralis fossil molecules are also more broad, the data described in the specimen in the morphology of the tube, spiral way, pen stone