I guess it is . . . it is fairly dense, looks organic and is more or less shaped like a short cylinder measuring 4" X 2" . . . don't know what it could be either. I initially thought it might be a vertabra but it does not have the proper structure. . . . I am guessing it might be a part of a tail secion of something large . . . I am only guessing.
Here is a photo of segments of a whale skeleton . . . promissing . . .no? The 4th piece from the upper right hand section looks sort of similar.
Here is another image not quite as good