The Nærsnes section, Oslo Region, Norway: trilobite, graptolite and conodont fossils reviewed

New collections of trilobites, graptolites and conodonts, the latter figured for the first time, have been made from an unbroken, uniform sedimentary succession across the Cambrian–Ordovician Boundary. The zonal conodont Cordylodus proavus first appears in undoubted pre-Tremadoc strata. Additional conodonts show that the base of the Tremadoc lies within beds correlative with the Symphysurina Zone of North America and at a level above the base of the Hirsutodontus simplex subzone of the C. proavus Zone. Cordylodus lindstromi and Iapetognathus preaengensis first appear at the base of the Tremadoc. The olenid trilobite Jujuyaspis occurs in the same lower Tremadoc interval and has great potential for interregional correlation.