大兴安岭中部奥陶纪介形类化石的发现及其意义

在内蒙古自治区苏呼河一带,前人所划属志留—泥盆纪的“鹿沟组”及上志留统“古尔斑河组”发现丰富的介形虫、辨鳃、腕足、三叶虫化面。经鉴定其中介形虫有:Brevibolbina,Ctenentoma, Cerafobolbina,Hingganobolbina,Sibiriobolbina,Sigmobolbina等,共计12个属、11个种（1新属、4个新种）。以上化石主要产于苏联西北部、北欧及中欧地区的中—晚奥陶世地层之中,这一介形虫类化石群在我国大兴安岭地区,尚属首次发现,它对我国奥陶纪地层的划分及与国际上的对比研究具有重要的意义。

THE DISCOVERY AND SIGNiFiCANCE OF ORDOVICIAN OSTRACODS IN THE CENTRAL GREATER KHINGAN MOUNTAINS

Very abundant ostracod. lamellibranch, brachiopod and trilobite fossils have been found in the strata assigned by predeccessors to the Silurian-Devonian "Lugou Formation" and Upper Silurian "Gurban River Formation" in the Snhu River area, Inner Mongolia. The ostracods are represented by Brevibolbine, Ctenentoma, Ceratobolbina, Higganobolbina, Sibiriobolbina and Sigrnobolbina, including 12 genera and 11 speeied （1 new genus and 4 new species）. The above-mentioned fossils are mainly distributed in Mid-Late Ordovician strata in Estonia and Lithuania of the U.S.S.R., Germany and Czechoslovakia of Central Europe and Norway and Sweden of Northern Europe. This ostraeod fossil assemblage was for the first time discovered in the Greater Khingan Mountians region of China. It is of very important significance for the study of China’s Ordovician biogeographical provinces and the international stratigraphieal correlation.