I never did hear back from Dr Kent.  I did find a very enlightening page on Elasmo.com titled "C. Carcharias Time and Place", in which the author, Lutz Andres, examines the various claims regarding Miocene Great Whites, and concludes that none of the reports is entirely reliable and that the Great White did not exist in the Miocene.  I tend to agree with his conclusion.  I know that some of the members here have been hunting the Bay for decades, and I have to believe that someone here would have found one if they were there to be found.

Now watch, having said that, I wouldn't be surprised if someone posts a Bay GW tooth within a week!