新疆乌什下寒武统肖尔布拉克组软舌螺化石

首次描述了采自新疆乌什县乌什磷矿肖尔布拉克组中部Kepingaspis-Tianshanocephalus带中的2个软舌螺新种Conotheca xinjiangensis sp.nov.,Nitorcornus wushiensis sp.nov.和下部Ushbaspis带中的1个软舌螺未定种Adyshevitheca?sp.。这些软舌螺化石材料为研究新疆乌什地区下寒武统中部地层与邻区相当层位的对比提供了新的证据，认为肖尔布拉克组中部2个三叶虫化石带和其中的软舌螺化石相当于我国扬子地台下寒武统沧浪铺阶中部，即乌龙箐亚阶和红井哨亚阶之间，可与俄罗斯西伯利亚和哈萨克斯坦下寒武统波特姆阶(Botomian)中的三叶虫带Ushbaspis和软舌螺带Erraticornus-Nitorcornus带对比。

HYOLITHS FROM THE LOWER CAMBRIAN XIAOERBULAKR FORMATION OF WUSHI, XINJIANG

The hyolithid fossils studied herein were collected from the Lower Cambrian Xiaoerbulake Formation at the Wushi Phosphorite section in Wushi (Fig.1), Xinjiang. Two new hyolithid species, Conotheca xinjiangensis sp. nov. and Nitorcornus wushiensis sp. nov.,and an indeterminate species ?Adyshevitheca sp. are systematically described. C. xinjiangensis sp. nov. and N. wushiensis sp. nov. occur in the trilobite Kepingaspis\|Tianshanocephalus Biozone (Bed 11 of Zhou, 2001), while ? Adyshevitheca sp. occurs in the trilobite Ushbaspis Biozone (Bed 8 of Zhou, 2001) of the Xiaoerbulak Formation (Fig.2). These hyolithid fossils provide new evidence for the biostratigraphic correlation of the Xiaoerbulake Formation with the corresponding horizons in the adjacent areas. Trilobite biostratigraphy suggests that the two fossil horizons of the Xiaoerbulake Formation can be correlated with strata of the middle Canglangpuan stage on the Yangtze Platform, and with the Botomian stage on the Siberia Platform and in Kazakstan.