The Lower Devonian of Nevada provides a reference sequence of nine conodont faunas, five of which are also at Royal Creek, Yukon Territory. The first appearance of Icriodus woschmidti is comparable to that in the lower Gedinnian in Europe; the Polygnathus dehiscens-P. foveolatus lineage correlates with the Emsian. Directly associated graptolite and brachiopod zones in Nevada date the intervening conodont succession as upper Gedinnian and Siegenian.

Five faunas characterize the lower Middle Devonian (Eifelian) in New York ; at least two of the lower three are present in the Illinois Basin. Illinois Basin faunas correlative to the upper two New...