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

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	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Recent		1		Equus
		Pleistocene
Tertiary	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Pliocene	8	9	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	Plesihippus, Hipparion
						Pliohippus, Hippidium
						Protohippus
		Miocene	13	22	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Merychippus
						Parahippus
						Hypohippus
						Anchitherium
		Oligocene	13	35	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Miohippus
						Mesohippus
		Eocene	20	55	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	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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