https://geo.libretexts.org/Courses/MiraCosta_College/Oceanography_101_(Miracosta)/02%3A_Evolution_of_Life_Through_Time/2.24%3A_Paleogene_Period_(66_to_23_million_years_ago)
2.24: Paleogene Period (66 to 23 million years ago) - Geosciences LibreTexts
million years agopaleogene periodgeoscienceslibretexts