A subdivision of the early Cambrian olenellid trilobite fauna. The trilobite faunas of the early Cambrian can be divided into two main regional groups: the olenellid fauna found in north-western Europe and N. America, and the redlichiids in Asia, Australia, and N. Africa. The olenellid fauna is also subdivided into two provinces: the Atlantic Province on the southern and eastern flank of the Iapetus Ocean, and the Pacific (or American) Province on the northern and western margins. The names Atlantic Province and Pacific Province have also been applied to the Ordovician trilobite and graptolite faunas in the same areas.