CHAPTER XI 



THE EXTINCT FORERUNNERS OF THE HORSE 



Of few mammals has the record of their past 

 history been so well preserved as is the case with 

 the horse and its existing relatives ; for as we 

 descend through the five stages — Pleistocene, 

 Pliocene, Miocene, Oligocene, and Eocene — of the 

 uppermost, or Tertiary, epoch of geological history 

 we can trace a more or less complete gradation 

 from the horses of the present day to primitive, 

 many-toed animals, scarcely larger than foxes, and 

 presenting few of the features which render the 

 horse and its relatives such a remarkable group. 

 In other words, from tall, single-toed quadrupeds, 

 adapted for grazing on open plains, and endowed 

 with the maximum speed of which mammalian 

 organisation is capable, we can trace the passage 

 through smaller, three-toed forest-dwelling and 

 browsing animals, to small and almost fox-like 

 creatures which in all probability frequented the 

 swampy shores of lakes and marshes, and were 

 little if any faster than badgers. 



How long a period was the evolution from the 

 little four-toed Hyracotherium of the Lower Eocene 



839 



