Protosalvinia (Foerstia) Zone in the Upper Devonian Sequence of Eastern Ohio, Northwestern Pennsylvania, and Western New York

摘要

Remains of Protosalvinia (Foerstia), a fucalean alga restricted to Upper Devonian strata, are locally abundant in the Chagrin Shale Formation along Conneaut Creek in Ashtabula County, Ohio. Protosalvinia also occurs along Conneaut Creek and Little Elk Creek in Erie County, Pennsylvania, where it is confined to a 10-m zone near the base of the Ellicott Shale Member of the Chadakoin Formation. This Protosalvinia (Foerstia) zone can be traced eastward to Chautauqua County, New York, permitting correlation of undifferentiated Chagrin Shale of the Ashtabula, Ohio, area with the more finely divided stratigraphic sequence of northwestern Pennsylvania and western New York.