Eocene

The Eocene epoch began 56 million years ago and ended 33.9 million years ago. The perissodactyls include the horses, rhinoceroses, and tapirs; among the artiodactyls are the deer, cattle, and sheep. An early horse ancestor, the dawn horse, known in North America as Eohippus, is among the fossil perissodactyls found in the lower Eocene rocks of both North America and Europe.

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