Your opinion is uninformed.http://www.nytimes.com/2007/04/12/science/12cnd-dino.html?ex=1185163200&en=82cb6ea2c09a6749&ei=5070
Gee, now that article changes my opinion. /s
It would have to have never rained in Montana and the Dakotas for millions of years for that bone not to be totally petrified.