MARINE VERTEBRATE REMAINS FROM A LATE-MIDDLE DEVONIAN BONE BED AT THE DELEWARE LIMESTONE/OHIO SHALE BOUNDARY, LOGAN COUNTY, OHIO AND LITTLE HARDWICK CREEK IN VAUGHN'S MILL, KENTUCKY
The East Liberty Bone Bed was first defined by Wells (1944). Wells described the geology of the East Liberty Quarry and a limited explanation of the inclusive vertebrate material with no explanation as to how the bone bed formed. Conkin and Conkin used Wells’ findings to help describe paracontinuities but actual research at this quarry has not been ongoing since the 2000s. The East Liberty Bone Bed is between the boundary of the Middle Devonian, Givetian Stage, Deleware Limestone and the Late Devonian, Frasnian Stage, Ohio Shale in East Liberty, Ohio. A detailed look at this site is needed to help understand how vertebrate material accumulated at the bone bed.
The Little Hardwick Creek Bone Bed was first described by Brett et al. (2003). Three different bone beds were identified at Little Hardwick Creek by Brett et al., bone beds A, B and C, oldest to youngest, respectively. Bone Bed C was analyzed for faunal determination of this rich Late Devonian Famennian vertebrate concentrated layer.
Both the East Liberty Bone Bed and the Little Hardwick Creek Bone Bed has a mixture of both Late Frasnian and Famennian conodont species, thus representing a possible correlative boundary between the Frasnian and Famennian (Brett, et al., 2003; Mann et al., 2007). Micro-vertebrate material consists of abundant conodont elements, acanthodian and thelodont scales, arthrodire plates and chondrichthyan dermal denticles and teeth. Chondrichthyans are represented by Protacrodontidea, by members of the genus Protacrodus Jaekal 1921, and Cladoselachidae, by members of the genus Ohiolepis, Phoebodus and Stethacanthus.