Original page content written and completed by:
pdp -- 4/30/94
brs 10/4/95 -- format updated, and plant search added.
7/7/00 -- exhibit expanded to five pages.
Oligocene pages updated to reflect Geological Society of America (GSA) 1999 Geologic Timescale, compiled by A.R. Palmer and J. Geissman
-- S. Rieboldt, Nov. 2002