"the Dawn Horse"
The Dawn Horse
Public DomainThe Dawn Horse - Credit: Heinrich Harder

Remains of theĀ 'Dawn Horse' (Eohippus or Hyracotherium) were first found in England by Richard Owen in 1841, but a full skeleton wasn't discovered until 1876, in North America. Owen believed it was a relative of the hyrax, due to its large incisors, and estimated its origin in the early Tertiary period, approximately 60-45 million years ago. It stood about 20cm high and 60cm long.