380 



EARTH FEATURES AND THEIR MEANING 



lacking the lighter background of the sky, we make out with less 

 distinctness the U -valley, either with or without the albs to show 

 that the sculpturing process has been interrupted by uplift. 



The sculpture accomplished by ice caps. In the case of ice 

 caps, the only rock exposed is found in the neighborhood of the 



FIG. 407. Two views illustrating successive stages in the shaping of tinds 

 or "bee-hive" mountains. 



margin the projecting islands known as nunataks. It is es- 

 sential for the existence of the ice cap that the rock base should 



