The geological era that began about 66 million years ago and extends to the present. It followed the Mesozoic era and is subdivided into the Palaeogene and Neogene periods. The Cenozoic is often known as the Age of Mammals as these animals evolved to become an abundant, diverse, and dominant group. Birds and flowering plants also flourished. The era saw the formation of the major mountain ranges of the Himalayas and the Alps.

http://www.ucmp.berkeley.edu/cenozoic/cenozoic.php Survey of the Cenozoic era by the University of California Museum of Paleontology