[Junior]

Cool. Thinks for the link. I know they're sure the bone has not been worked up from pre-K-T strata. However, I wonder if they've allowed for a bones that might have weathered out of pre-K-T strata (much like we find happening nowadays in places like Mongolia) and then being re-interred, as it were, in later strata. I wonder how one would check for that.

[AndrewC]

and then being re-interred, as it were, in later strata. I wonder how one would check for that.

Read that PDF and you will see that they considered that. The PDF also has a graphic which shows the fossil in relation to the cretaceous/tertiary boundary. But I have doubts whether anything could be recognizable after being buried, eroded, buried and eroded again.