CHAPTER XII 

 LOW AREAS OF THE EAETH 



180. Level Areas. At different places on the earth's 

 surface there are broad extents of nearly level land. Here 

 the drainage is often poorly developed, and there are slight 

 depressions often of considerable area. After a rainfall the 



A LEVEL, POORLY DRAINED AREA. 

 Such an area is called young. 



shallow water stands in these depressions until it evapo- 

 rates or sinks into the ground. In the parts where the 

 drainage has been developed, the streams flow with slow 

 currents in channels of little depth. 



When excavations are made, the rock beneath the soil is 

 often found in horizontal or almost horizontal layers. 

 Where the elevation of these areas is considerable, the 

 streams may have deep gorges and the surface may be well 

 dissected. Where these level areas are low, they are called 



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