Abstract: Associated with each particular taxa, there is a time of first appearance (FAD) and last appearance (LAD). It is possible (and exceedingly likely) that the taxa originated before it was first seen and/or went extinct after it was last seen. Palaentologists find these true times of origination and extinction most enlightening. Hence, several different methods have been developed for range extension. We will look at two of these methods and compare their results. This is work with Dr. Sheets (Physics).