PALEOZOIC FISH REMAINS AND ICHTYOLITHS FOUND IN A LATE TO MIDDLE DEVONIAN BONE BED AT THE BOUNDARY BETWEEN THE COLUMBUS LIMESTONE AND THE OHIO SHALE IN EAST LIBERTY, OHIO

A paleontologically important, well preserved macro- and micro-vertebrate fauna was obtained from a bone bed at the boundary between the Columbus Limestone and the Ohio Shale in East Liberty, Ohio. The exposure occurs at the uppermost portions of the East Liberty Quarry, located adjacent to U. S. Highway 33. The quarry exposes approximately 11 meters of the Columbus Limestone and overlain by 5 meters of the Late Devonian Ohio Shale, in spots covered by the Olentangy Shale.

This bone rich bed occurs within a distinct, 10 cm layer that spans portions of the exposure. The lithology of the layer consists of a maroon-gray to brownish-gray, fine to medium-crystalline dolomitic limestone. Copious well preserved macro- and micro-vertebrate remains and phosphatic nodules are scattered primarily on the upper surface and within the upper two –to- three centimeters of the layer.

Macro-vertebrate remains include disarticulated arthrodire plates and isolated skeletal elements. Micro-vertebrate material consists of abundant conodont elements, acanthodian scales, chondricthyan dermal denticles and teeth. Chondrichthyans are represented by the cladoselachids Stethacanthus, Symmorium, Ohiolepis, cladodonts, by the phoebodontids Phoebodus, by members of the genus Protacrodus, as well as several undescribed species.

Faunal comparison, based on icthyoliths and conodonts, of the bone beds found in the Columbus Limestone (Wells 1944) and those found within the East Liberty Quarry do not correlate. Given this dissimilarity, future work will focus on faunal correlation between the East Liberty bone bed and the bone beds found within the Delaware Limestone and the Ohio Shale. Additionally, the vertebrate fauna appears to be similar to the bone bed that can be found at the Little Hardwick Creek in Clay City, Kentucky (Brett, et. al. 2003). Given this similarity, future work will focus on careful lithostratigraphic, sequence stratigraphic, and biostratigraphic analysis, as well as faunal correlation with the Little Hardwick Creek.