Orthonota is yet another of the many Pelecypod species that can be found in the Mahantango formation of central Pennsylvania. It's a very obvious shell when spotted as it is long and narrow. In fact it look almost exactly like modern Razor Clams found in the oceans today. Typically I the shells I find are 3-4" long and about an inch wide although I've found some smaller specimens as well. Due to the large, elongated shell good specimens can be hard to find and extract from the rock.
Modern Razor Clam shells
Fossil Orthonota from the Mahantango