The website states the age of the fossils in millions of years before the present, but also makes continual references to the technical names for periods of geologic time, such as “Paleozoic,” “Cretaceous,” and “Bathonian,” in the interest of accuracy.  Many people are not familiar with some or all of these terms.  Below is a reproduction of the geologic timescale showing the order and time ranges associated with all of terms used here.  It is borrowed from the University of Colorado website (http://www.csmate.colostate.edu/cltw/cohortpages/viney/nh_geologic_time_scale_large.gif)

Other timescales can be found on the internet.  For more information on geologic time, there are many helpful websites, but one to visit is: http://pubs.usgs.gov/gip/geotime/