BIOSTRATIGRAPHIC SIGNIFICANCE AND PALEOGEOGRAPHIC IMPLICATIONS OF CAMBRIAN FOSSILS FROM A DEEP CORE, WARREN COUNTY, OHIO

A deep core from Warren County, Ohio, has yielded numerous fossils of Cambrian age. The specimens, which are among the first recorded from C ambrian rocks of Ohio, suggest revisions in the inferred ages of the E au Claire and Mount Simon Formations in the Cincinnati Arch region. Tr ilobites indicative of Dresbachian (late Middle Cambrian to early Late Cambrian) and possibly Franconian (Late Cambrian) age are present in the upper Eau Claire Formation. By implication, the underlying Mount S imon Formation must be of earlier Dresbachian age or perhaps older. Id entified trilobites from the Eau Claire Formation seem to be character istic of inner-shelf lithofacies of Laurentia. Other body fossils from the Eau Claire Formation include inarticulate brachiopods and a grapt olite. Body fossils in the lower Knox Dolomite include trilobite scler ites and echinoderm ossicles. Trace fossils are present in both units.