In the 1960s Paleontologist John Wells of Cornell was studying the annual growth rings corals. He was able to slice and polish the samples and identify daily growth lines and larger distinctions representing the annual cycle of the seasons. His samples were fossils from the Devonian Period and when he counted up the growth it indicated the earth spun much faster with 400 days in each year. Further research shows that the earth day during the Cambrian there were 430 days, by the end of the Jurassic there were 385 days. Now there are 365.24 days in a year.