9304513 Fastovsky PIs will conduct a statistical data analysis of fossil material collected by the Milwaukee Public Museum "Dig a Dinosaur" program. Proposed analyses will test the hypothesis that dinosaurs dwindled gradually in diversity and abundance during the last 2.2 million years of the Cretaceous. This research will also address the general problem of determining rate of extinction, including taphonomic issues, sampling and preservation biases, and (paleo)ecologic controls.