I.I I l.( FS OF UNEQUAL HARDNESS 



93 



n-si>tanl portions of a land area more or less distant from streams 

 arc worn down more readily than those which are more resistant. 

 If gn-at areas of high land are capped with hard rock, they are likely 

 to i (ina in high after surrounding areas of less resistance are brought 

 low. If the hard capping remains over a small area instead of a 



I-'k. 82. The Enchanted Mesa. A striking butte in New Mexico. The name 

 mrsa is not commonly applied to elevations of such small summit area. (R. T. 

 Chamberlin.) """""" 



large one, the elevation is a butte, a hill, or a mountain; if over a 

 large area, a plateau. Many buttes and small mesas are but 

 remnants of former plateaus. A feature of buttes and mesas capped 



Kiir. 8}. Hogbacks; Sec. 22, T. 16, N., R. 112 \Y.. Wyoming. The rock which 

 occasions the hogbacks is the Lazeart sandstone at the base of the Adaville forma- 

 tion. (Veatch, U. S. Geol. Surv.) 



