 This has made it possible to correlate terrestrial sediments with the time scale from marine sediments, and compare them directly with global climate change and mass extinctions.Paleontologists have moved towards finer zonation of terrestrial fossils, with the potential to divide the Cenozoic into time intervals of 300,000 years or less.They have also attempted to convert some of the intervals, including the Wasatchian age/stage and Clarkforkian age/stage, into biostratigraphic units.