Funded by a grant from the Petroleum Research Fund, part of the American Chemical Society, Dr. Cushman studies fossil pollen and spores he has collected from a remote area in southwestern Wyoming. This past July and August, he spent three weeks gathering samples from the deposits of ancient Fossil Lake, located in the Fossil Butte National Monument. He recently received a two-year grant to study terrestrial deposits in eastern Utah and western Colorado. Coming up with unsatisfactory results, he transferred his study and funding back to Fossil Butte and the Green River Formation. By studying pollen, Dr. Cushman is able to determine the conifers and flowering plants living during a given period of time.
Fossil spores indicate ferns and other simpler plant forms prevalent during the same period.
By comparing my samples to the scientific literature, I've been able to place them within the Eocene time period. Plants from this time period are similar enough to modern plants for the same genus names to be used. We can even determine the approximate annual rainfall, which tells us whether the climate was humid or arid. Dr. Cushman describes the Fossil Lake basin, a dry lake bed located at an elevation of more than 6,000 feet above sea level, as having deciduous hardwood trees such as oak and hickory during the Eocene time period. He has even found evidence of palm trees.