Abstract:
The Lower-Middle Cambrian boundary in Gondwana and Laurentia is correlatedusing the trilobites Bathynotus,Microryctocara,Pagetia prolata,and Oryctocephalus indicus from South China and the western United States．Oryctocephalus indicus is suggested as a candidate for thedefining taxon for the base of the Middle Cambrian Series and its lowest stage in Laurentia and South China．
