The material dealt with in this paper was collected in 1955 by Mr.L.H.Wong and others of 241.Party of the Geological Bureau of North China,Ministry of Geology,at a locality about 20 km north-east of Beiyin Obo,InnerMongolia.According to the collectors’field observation,all the corals occur ina limestone imbedded in a red sandstone series,striking east to west and dip-ping to north.The thickness of the red sandstone series is unknown,it is over-lain by the Upper Carboniferous Triticites bed.The coral-horizon is estimatedat about 2,500 meters below the Triticites bed.No detailed stratigraphical dataare available.The corals described here comprise the following species