Chapter IX: The Ancestry of the Horse

North America in the Eocene age, 160; appearance of early
horses, 163; early domestication of the horse, 165; the toes of
horses, 166; Miocene horses small, 167; evidence of genealogy of
the horse, 170; meaning of abnormalities, 170; changes in the
climate and animals of the West, 174; references, 176.