The Epoch in the Tertiary Period is divided into two parts: the EOCENE (6 letters) and the Neocene (7 letters). The EOCENE Epoch began about 56 million years ago and lasted until about 33.9 million years ago. During this time, the climate was warm and humid, and the first primates appeared. The Neocene Epoch began 33.9 million years ago and lasted until about 23 million years ago. During this time, the climate cooled and the first horses, deer, and camels appeared.