Early Cambrian Appalachian archaeocyaths: Further age constraints from thefauna of New Jersey and Virginia, USA

New data allow us to correlate the Early Cambrian archaeocyathan faunas of the Appalachian (eastern) and Cordilleran (western) faunal provinces of Lau rentia. The precise relationships of fossil assemblages between these provi nces have hitherto been controversial, with the correlation of the Elliptoc ephala asaphoides Fauna posing particular problems. New and revised data (i ncluding the new taxa Sckwicyathus tillmani nov. sp, DEBRENNE & A. ZHURAVLE V and Archacosycon balsami nov. sp. DEBRENNE & A. ZHURAVLEV On archaeocyath an assemblages from the Appalachians New Jersey and Virginia allow correlat ion of these assemblages to the middle Bonnia-Olenellus Zone of the Pacific Laurentia (Late Botoman) and the Elliptocephala asaphoides Fauna with the middle-upper Bonnia-Olenellus Zone (Late Botoman-Early Toyonian). The Appal achian archaeocyathan assemblages are not endemic but originated from archa eocyaths of the Pacific Region in or near the Middle Botoman; then, during the Middle Botoman-Late Bot;oman, they migrated northward along the Appalac hian margin of Laurentia (in term of modern coordinates). We discuss here t he development and the extent of influence of the Hawke Bay regressive even t, and the pattern of archaeocyathan migration as the Appalachian margin of Laurentia drifted northward into equatorial latitudes.