THE WORK OF RUNNING WATER 



69 



there the valley which develops from it follows. The crookedness 

 of many valleys is thus explained. 



a b c d e f ff h i j k I 



Fig. 61. Diagram showing a series of young streams along a coast. 



k I 



Fig. 62. The same streams shown in Fig. 61, after a period of growth; 

 d, /, and / have grown much beyond their neighbors. 



bed 



f 



9 h 



Fig. 63. The streams of Fig. 62 developed still further; d, f, and / have 

 developed so far as to stop the growth of most of the others. 



The permanent stream. Water commonly flows in gullies only 

 when it rains and when snow melts, and for a short tome afterward; 

 but many valleys developed from gullies finally have permanent 

 streams. Where does the water for such streams come from? 



