Parallelodon carbonarius (Cox 1857) is a bivalve with distribution from the older Pottsville Group to the younger Conemaugh Group in Ohio and Pennsylvania. This is the first specimen of this species that I have found in over three years of searching through the Brush Creek limestone and the Pine Creek limestone. The fossil was recovered in the limestone proper. It measures 45 mm in length. Morningstar (1922) wrote that “It is characterized by surface sculpture of prominent, regular, radiating plications which become considerably larger and stronger on the flattened posterior portion below the hinge line”.
There are four good figures (Sturgeon et al., 1979, Plate 3, Fig. 4-8) to observe in the 1979 book Pennsylvanian Marine Bivalvia and Rostroconchia of Ohio. They are the same as this specimen and the species identification is correct. The original by Cox, Arca Carbonaria is missing the lithographed plates in the online versions, so I could not find the original figure yet.
- Cox, E.T., 1857, Geological Survey of Kentucky
- Hoare, R.D., 1979, Bulletin 67: Pennsylvanian Marine Bivalvia and Rostroconchia of Ohio, State of Ohio Div. of Geological Survey
- Mark, C. G, 1912, The Fossils of the Conemaugh Formation in Ohio, Geological Survey of Ohio, Fourth Series, Bul 17, pp. 261-325
- Morningstar, H., 1922, Pottsville fauna of Ohio. Ohio Geological Survey, Bulletin 25 pp. 1-312