CREATION BY EVOLUTION 



groups named. They were all three toed, but the side toes 

 in most species were so small that they did not touch the 

 ground. Pliohippus, which lived only in North America, 

 had the smallest side toes; Hipparion, which lived in North 

 America and in Europe, had the largest side toes and had 

 teeth of a distinctive pattern. 



In the Pleistocene epoch, which followed the Pliocene and 

 which included the Ice Age, horses were abundant in both 

 America and Europe. These horses, which were presumably 

 the descendants of Pliohippus, are so nearly like the horses 

 now living that they have all been placed in the genus Equus. 

 Pleistocene deposits found in all parts of the United States, 

 from California through Texas to Florida and northward to 

 Nebraska and Pennsylvania, have yielded remains of horses, 

 some smaller than even the smallest living pony, some as 

 large as any living horse, and one species {Equus gigafUeus) 

 the largest horse known. 



The Pleistocene epoch is the period of maximum develop- 

 ment of the horses in number, size, and variety. During 

 this epoch horses made their way from America by way 

 of Alaska and an isthmus across Bering Sea to Asia and 

 Europe. Remains of Pleistocene horses are found in Alaska. 

 The ice sheet of the glacial age, although it covered north- 

 eastern America, did not extend west of the Rocky Mountains, 

 so that Alaska was then temperate enough to permit horses 

 to live there. During this epoch horses made their way also 

 to South America over the Isthmus of Panama and spread as 

 far south as Argentina. 



The most notable evolutionary changes in the horses con- 

 sist of an increase in size, changes in the size and structure 

 of the teeth, and, most conspicuous of all, changes in the 

 form of the foot. The stock from which the horse was 

 derived was probably iive-toed, the foot conforming in its 



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