THE FORERUNNERS OF THE HORSE 275 



geographical range, having apparently originated in 

 Western Europe (England) and migrated by way 

 of Asia and what is now Bering Strait as far south- 

 east as New Mexico. This migration of Eohippus 

 shifted the scene of the evolutionary drama to our 

 own country [America], for, while the remains of 

 succeeding genera are increasingly numerous in 

 North American rocks from the Wasatch on, it is 

 only from time to time that European representa- 

 tives appear, in each case evidently derived from 

 migratory North American types." 



Lastly we have the European Hyracotkerium, 

 which, as mentioned above, apparently differs from 

 the allied American genus solely by the somewhat 

 simpler character of the upper cheek-teeth, in which 

 the cross-crests still retain their two constituent 

 tubercles. Remains of the typical H. leporimun 

 have been obtained from the London Clay near 

 Heme Bay, Sheppey, and Harwich {Pliolophiis), 

 and also from the Red Crag of Suffolk, which, as 

 in this case, often contains fossils washed out of the 

 London Clay. The remains include several more 

 or less imperfect skulls and lower jaws and one 

 example of the femur. 



Here our knowledge of the evolutionary history 

 of the horse comes abruptly to an end. It is true, 

 indeed, that the late Professor E. D. Cope hailed 

 a still earlier animal, Phenacodus primcsvus, of the 

 basement, or Puerco, Eocene of America, as the 



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