MESAS AND FOOT-HILLS 



203 



that one meets with in the plateau region are 

 not of the same make-np as the clay bnttes of 

 Wyoming or the gravel hills of New England. 

 They have a core of rock within them and are 

 nothing less than washed-down foot-hills. Yon 

 will often see a chain of them receding from the 

 range toward the plain, and growing smaller as 

 they recede, until the last one is a mound only 

 a few feet in height. They are flattening down 

 to the level of the plain — sinking into the 

 sandy sea. 



Usually the lomas are seen against a back- 

 ground of dark mountains of which they are 

 or have been at one time a constituent part. 

 For the lomas are the outliers from the foot- 

 hills as the foot-hills from the mountains proper. 

 They are the most worn because they are the 

 lowest down in the valley — in fact the bottom 

 steps which receive not only their own wash but 

 that of all the other steps besides. The moun- 

 tains pour their waters and loose stones upon 

 the foot-hills, the foot-hills cast them ofiE upon 

 the lomas, and the lomas in turn thrust them 

 upon the plains. But the casting off effort be- 

 comes weaker at each step as the sides of the 

 hill become less of a declivity. When the little 

 hill is reached the sand-wash settles about the 



Worn-down 

 mountamn. 



The mown- 

 tain-wash 

 and its 

 effect. 



