25 Paleozoic Era ends. Mesozoic Era Begins. 26 Triassic Period. 27 Jurassic Period. 28 Cretaceous Period.
Dinosaurs become extinct.
29 Mesozoic Era ends. Cenozoic Era and Tertiary Period begin. 30 First evolution of frontal lobes in the brains of primates. Giant mammals flourish. 31 End of Pliocene Period.