Many months ago this topic was brought up but we did not really come to a conclusion. As almost a thousand people have joined this website since the question was originally posed, it is worth repeating to determine if anyone has any fresh perspectives or information on the matter. In short, I was always under the impession that belemnites became extinct along with ammonites at the end of the Cretaceous period. Yet I noticed in EH Clarkson's Invertebrate Palaeontology and Evolution 4th ed. (1998), mention was made of a few belemnites continuing into the Tertiary before becoming extinct. This is very interesting but unfortunately the book did not quote the reference for the claim or the location of these anomalies. Personally I would assume that these rare finds may be redepositions from earlier contexts, but this is merely a gut reaction. Does anyone have any further information on these enigmatic survivors or is it all a question of misinterpretation of contexts?