ORDOVICIAN GRAPTOLITE BIOSTRATIGRAPHY OF GONGCHENG, GUANGXI, CHINA

The present paper deals with two sections of Huang’ai,Shengping and Tianlingkou Formations in Gongcheng,Guangxi Autonomous Region used to be regarded as of Cambrian age due to the lacking of fossils.In 1997 Ordovician graptolites indicating mainly Middle Ordovician were first discovered from the rocks,and briefly reported in 1999.The details of these two sections are presented herein,and biostrati- graphy discussed.The sections,located in the northeast of Gongcheng,Guangxi with considerably abun- dant Ordovician graptolites,include the following 8 graptolite zones(in descending order):8.Nemagrap- tus gracilis,7.Pterograptus elegans,6.Nicholosonograptus fasciculatus,5.Acrograptus ellesae,4.Undu- lograptus austrodentatus,3.Exigraptus clavus,2.Isograptus caduceus of.imitatus,1.Didymograptus (E.)abnomis.The graptolite biozones are comparable with those in SE China,Australia,Canada,North America and Great Britain.The succession is believed to be representative of deep-water‘Isograptus’fa- cies in the Zhujiang Region of South China.