li^ THE NEW EVOLUTION ' ^^^^ 



All through the sedimentary rocks of the earliest 

 epoch of the Tertiary — the Eocene or "dawn time" — 

 there are records of an abundance of little creatures 

 much resembling those of the Oligocene but still more 

 diminutive in size. They also had a main central toe 

 with well developed lateral toes on each hind foot, 

 but the fore feet were provided with four toes instead 

 of three. The muzzle portion of the skull was rela- 

 tively shorter in the little very early horses than in 

 the larger later horses, so that the eyes were about 

 midway between the ears and the tip of the nose 

 instead of being nearer the ears as in the later horses. 



The oldest member of the group of four-toed horses, 

 which is also the oldest member of the great group to 

 which belong all the horses, was a little creature no 

 larger than a fox called Eobippus or the ' 'dawn horse. ' ' 



While no member of the horse family has five com- 

 plete toes, some of the little four-toed ones have in 

 the foot an extra small bone of splint-like shape which 

 can only be interpreted as the representative of a 

 fifth toe. 



This account of the different types of horses, begin- 

 ning with those of the present day and running back 

 further and further through geologic time to the very 

 earliest creature known which can be called a horse 

 leads us by easy stages to an animal which is very 

 different from any kind of horse we ever saw. With- 

 out a knowledge of the intermediate types we would 

 never suspect that it had any affinity with horses. 

 Now if we reverse the picture we shall get a good 

 example of an evolutionary line. 



^74] 



