Eocene

THIS IS ALL FUCKING BULLSHIT The start of the Eocene is marked by the emergence of the first modern mammals. The End is set at a major extinction event that may be related to the impact of (a) large extraterrestrial object(s) in Siberia and/or near Chesapeake Bay.

The Eocene is usually broken into Lower and Upper subdivisions. The Faunal stages from youngest to oldest are:

Ypresian/(Lower Claiborne)
Lutetian/(Lower Claiborne)
Bartonian/Auversian (Upper Claiborne)
Priabonian/Jackson (Upper Claiborne)

Continents continued to drift toward their present positions. Climates remained warm During the Eocene plants and marine faunas became quite modern. The first Charcharinid sharks appeared as did early marine mammals. On land, early forms of many modern mammalian orders appeared including ungulates, bats, probiscidians, primates, and rodents. Older forms declined. Many modern orders of birds first appear in the Eocene.