Dicotyles protervus (?)
Found in the water off of Flag Ponds Nature Park, this was an exciting and strange discovery. I brought it home expecting it to be some cetacean bone that I could not identify, but had no luck searching for a match at home. After digging on my own, and with the help of forum members, the staff at Flag Ponds, and the paleontological curatorial staff at Calvert Marine Museum, it was finally identified as a peccary astragalus bone (approximately rear knee joint) matching one in the museum's collection. Although it is a land animal found in an area that was a sea during the miocene, from which era most of the fossils came, the museum expects that it is, indeed from the miocene era. You can see more about Maryland Miocene Peccaries here.