HOW MANY "VANPORT/OBRYAN" UNITS REALLY EXIST?

Uses of the name "Vanport" for a marine limestone of Desmoinesian age (Pennsylvanian, Allegheny Group/Formation) grew from its type section in western Pennsylvania, were carried along the Ohio outcrop to cross the Ohio River into northeastern Kentucky. This was in spite of the fact that there was an area near the middle of the Allegheny outcrop belt in eastern Ohio where no limestone corresponding in concept or position to the "Vanport" could be identified. In turn this led to the recognition of a "northern Vanport" and a "southern Vanport" or even "Vanports I, II, and III" (Ferm, 1970). Rice (1994) attempted to resolve the problem by resurrecting the forgotten name "Obryan" from a locality along the Ohio River in northeastern Kentucky, applying it to rocks formerly called "southern Vanport." Rocks have now received that name as far north in Ohio as McArthur, Vinton County, a distance of about 100 km. A search of the literature reveals that the described localities that contain what might be called "Obryan" cluster into distinct areas, separated by areas where no marine rocks have been reported. Some of this absence of evidence may reflect reporting bias, emphasis on field areas by certain workers, and similar. Some of it may reflect genuine evidence of absence, however, and not all the rocks called "Obryan" are necessarily contiguous and generally coeval. Conodont paleoecology, along with physical criteria, helps to define basin geometries and conodont biostratigraphy, mostly employing Neognathodus in the NIFT analysis helps to establish temporal relationships within and between rock bodies.