ABSTRACT
A distinct brachiopod fauna, composed of a mixture of Cordilleran Old World Realm (OWR) endemic genera, cosmopolitan and formerly endemic genera of the Appohimchi Subprovince of the Eastern Americas Realm (EAR), spread across central and eastern North America duringthe late Eifelian (upper part kockelianus Zone). The breakdown of North American Devonian brachiopod provincialism in the late Eifelian-earliest Givetian, as evidenced by mixing of EAR and OWR faunas in the US Midcontinent Devonian carbonate platforms (Iowa and Michigan basins) and Appalachian and Moose River basins, was a direct consequence of widespread transgression of the North American craton at this time. This late Eifelian sea level rise resulted in profound expansion of cratonic seaways that provided avenues for migrations of elements of formerly isolated North American brachiopod faunas. Rocks deposited during this transgression can be correlated in most successions in North America, which corresponds to the sea level rise of Devonian eustatic Transgressive-Regressive (T-R) cycle 1 e. OWR migrants found in U. S. midcontinent and eastern U. S. faunas include Variatrypa (V.) arctica, Spinatrypa borealis, Spinatrypina, Carinatrypa, Warrenella, W. (Warrenellina), Gypidula, Kayserella americana, shallow water species of Emanuella (E. sublineata, E. meristoides), Subrensselandia, and possibly Stringocephalus. Some of these, as well as the OWR Independatrypa occur with coeval faunas in the Moose River Basin of eastern Canada. Elements of this paleobiogeo-graphically mixed fauna are now known to occur in coeval deposits of: the Murray Island Formation in the Moose River Basin in Ontario; the Bakoven (upper part), Stony Hollow, and Hurley members of the Union Springs Formation in eastern New York; the Delaware Limestone of Ohio; the Rogers City Limestone of Michigan; the Lake Church Formation of eastern Wisconsin; the Spillville and Otis formations in northern and eastern Iowa; and the Elm Point Formation of southern Manitoba.
