154 Life of Surface Deposits. 



features of their physiology they are similar, 

 as in size, in having trunks possessing great 

 delicacy of touch, and in the development of 

 tusks of great power and of pure ivory, but 

 they vary widely in external appearance and 

 their dentition was strangely different. The 

 crowns of the teeth of the Mastodon are cov- 

 ered with rows of conical protuberances, see. 

 Plate XXVIII (2), the jaws are filled with 

 closely set teeth like those of other mammals, 

 while the Mammoth has but one tooth at a 

 time in each jaw and that one a marvel of 

 structure. The mining processes of the Sho- 

 shone region have uncovered many fine speci- 

 mens of Mastodon jaw r s and teeth. 



MAMMOTH. 



In the Mammoth the student of animal 

 life will always find the furthest reach of mam- 

 malian development. The Shoshone region 

 had its full share of Mammoth life, for scarcely 

 a digging of any importance in Eastern Ore- 

 gon is without its list of Mammoth fossils. 

 Whether one considers the size of the indi- 



