I discovered something interesting. Today I was doing normal errands, found a fossil when to show Blathers, turned out to be a corpolite thing. Before I was able to sell it to retail I accidentally hit the power button without saving. So I had to go show blathers the same fossil again. I go show it to him, and this time it turned out to be a Raptor Skull. Which means you could reset your game for a different fossil each time til you get the one you wanted or a higher selling one or something. Thought I'd share this find.