【摘要】 浙江江山横塘宁国组Oncograptus带发现玉山笔石Yushanograp-tus,从而扩展了该属产地,并使其产出层位得到进一步厘定。更多还原

【Abstract】 Based on the specimen found in Yushan, Jiangxi, the genus Yushano-graptus was first described in 1964, but other materials have been seld-om reported since then. Recently the author discovered a specimen inthe Ningguo shale at Hengtang, Jiangshan, Zhejiang. Though there isonly one stipe and no sicula, the long primary stipe, Goniograptid bran-ching type and the straight tubular thecae show that it is Yushanogra-ptus indeed. According to all the features, the form resembles the typespecies Yushanograptus separatus, but the former’s branching orders aremore and the thecae of braches are stronger than those of the primarystipe. In view of only an incomplete specimen, it can’t be definitednow that the form is the mature form of Y. separatus or a new form. Yu-shanograptus described previously is only known to occur in the Didymog-raptus hirundo zone in the Ningguo shale, yet our specimen is found inthe Oncograptus zone so that the existing horizon of the genus can bedetermined more precisely.更多还原