CIRCULATION OF WATER IN BELT OF CEMENTATION. 575 



pendent curves. (Fig. 11.) The effect, so far as the geological action of 

 the underground water is concerned, would be approximately the same 

 whether the course of the water were that represented by fig. 10 or that 

 represented by fig. 11. This statement, applicable to a few points of 

 entrance- and one of exit, is equally applicable to a great number of points 

 of entrance and one of exit. The statement can be further extended to 



Fig. 11,— Ideal vertical section of the flow, through a homogeneous medium, of ground water entering at many points 

 along a slope and issuing at a single point at a lower elevation. 



an indefinitely great number of points of entrance distributed along the 

 contours of the slope as well as up the slope and to many points of exit at 

 or near the level of the valley. 



Disregarding the lateral movement after the water reaches the level 

 of ground water, the sea of gTound water at a given place might be con- 

 sidered as a column moving downward as rapidly as the increment of ground 

 water is added from above. However, the lateral movement which is super- 



