128 Life of Lower Lake Region. 



On Plate XXIII is a good figure of the 

 molar teeth of the Anchitherium from the 

 same region. 



In the continued wear and tear of the 

 cliffs of these fossil beds under frosts and 

 storms, the fragments that survive erosion 

 longest and therefore accumulate on the drain- 

 age surface, will always be the teeth and the 

 thickly enameled articulating 1 surface of the 

 large bones of the skeleton. The ends of the 

 femur, the ends of the tibia, and especially 

 the ends of the radius, are so distinctly marked 

 in the horse skeleton that they quickly catch 

 the eye of the collector. 



While the horses of the Miocene period 

 of the Shoshone region differed in size, it is 

 noticeable that the different parts of their 

 skeletons retain their relationship in size and 

 general form, so that any bone of any species 

 found to-day would at once be seen to con- 

 form to the type and show the size of the ani- 

 mal to which it must have belonged. The 

 mistaking of the bones of the young of a 

 larger species for the adult of a smaller one, 



