Page:Creation by Evolution (1928).djvu/278

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CREATION BY EVOLUTION

distinctive features and performed certain definite, well-known functions.


The Horse

The work of tracing the development of the horse is relatively easy, especially the forms of the horse that lived in America, for we have a very extensive series of fossil remains of American horses, taken from beds that are piled in succession one upon another (Fig. 1). More than 200 different kinds of American horses have been discriminated, and in addition to these about 30 kinds have been found in Europe and nearly as many more in South America, Asia, and Africa. Some beds have yielded thousands of teeth and jaws, some have yielded other parts of the bony frame, and most of the types of horses are represented by complete skeletons.


Geological Table Showing Evolution of the Horse

Period Epoch Length of
epoch in
millions of
years
Millions of
years ago
Kinds of horses
Quaternary Recent 1 Equus
Pleistocene
Tertiary Pliocene 8 9 Plesihippus, Hipparion
Pliohippus, Hippidium
Protohippus
Miocene 13 22 Merychippus
Parahippus
Hypohippus
Anchitherium
Oligocene 13 35 Miohippus
Mesohippus
Eocene 20 55 Epihippus
Orohippus
Eohippus

The genus that includes the modern horse (Equus) is represented today by the domestic horse (of which there are

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