THE WORK OF STREAMS 



179 



descent, and may reunite only to separate again a little 

 farther down valley. By this process the river is split into 

 many minor streams which shift continually and inclose 

 changing islands of sand and gravel. Such rivers are braided 



rivers. 



Stream meanders and flood-plain lakes. Even if nearly 

 straight in the beginning, a river must come to follow a 



FIG. 187. Meanders of the Jhelum River in the valley of Kashmir, India. 



serpentine (meandering] course (Figs. 186 and 187) on a 

 flood plain of low slope. This results primarily from the 

 fact that its sluggish current is turned against the banks 

 easily by irregularities of the channel, by the currents of 

 tributary streams, and in other ways. The current cuts 

 into the banks where it strikes them. As it issues from a 

 cut in the bank, it is directed against the opposite bank a 

 little farther downstream, and forms a curve there. The 

 development of this bend leads to the formation of another, 

 and so on. As erosion continues, the cuts tend to become 

 smooth curves, better adapted to the regular movement of 

 the current. At the same time the stream erodes these 

 curves, where the current is relatively swift, it builds lip to 

 flood level the opposite side of the channel, where the water 

 is slack. In this way it comes to follow a more or less regu- 

 larly curved course suited to its volume and gradient. As 



