RIVERS AND THEIR WORK 243 



EXERCISES 



1. How does the presence of soil and mantle rock help in the 

 formation of rivers? 



2. (a) What is the load of a river? (6) Where does it come 

 from? (c) What becomes of it? 



3. Make a comparison between any two rivers you know: (a) 

 in regard to their load; (b) in regard to the work they do. 



4. If the sediment at the bottom of a slow stream were consoli- 

 dated, what kind of rock would be made? 



6. Why are pebblef in the bed or on the banks of some streams 

 rounded and smooth? 



6. Why are there more pebbles of quartz than of other minerals? 



7. When a river meets an obstruction, why does it flow around 

 instead of over the obstruction? 



8. Describe a method by which you could find out very nearly 

 how fast a stream flowed. 



9. Why are swift streams straighter than slow ones? 



