Ill start by saying that I know very little about identifying bone fossils, but I found this at West Moreland park In Virginia which is on the Potomac river. They say you can find things like Whale vertebrae sharks teeth dolphin bones etc.. To me it looks like chert that has an interesting shape, but I figure I might as well clear up any doubts and post it and see if it might be a fossil such as a whale vert. I found no shark teeth while there...unfortunately. But I did find some other possible fossilized things that I post another time. Thx.