RIVER AND LAKE DEPOSITS 175 
of rock from every part of the Arkansas drainage area. 
In reality, the loss is not so uniform. At some places 
only a few inches would be removed, while in others 
the surface would be lowered several feet. 
Aside from that carried in solution, the load of rock 
materials is transported either in the suspended con- 
dition, as may be seen in any river during a flood, 
or else by dragging along the bottom. In the upper 
or torrential part of a stream valley, the material 
carried is usually coarse pieces of rock, and these 
decrease in size toward the mouth, where, because the 
slope is less, only the finer fragments can be moved. 
In a large river, the sediment does not all go down 
together in a single journey, but portions halt here 
and there, perhaps to form a bar, perhaps to enter 
into the structure of the floodplain, where they may 
stay for a long time; and then, as the river in meander- 
ing changes its course again, may be picked up and 
made to resume their journey. 
The sediment goes by steps with numerous halts, 
usually brief, but occasionally of long duration. Not- 
withstanding all temporary stops, during the course 
of ages the progress is plainly seaward. The ocean, 
the goal towards which the sediment is tending, with 
rivers as the carriers, is made the dumping-ground for 
the waste of the land. Aside from the great mass 
of sediment thus given to the sea, and strewn over its 
