PRINCIPLES CONTROLLING ORE DEPOSITS 



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of any kind, in which the water can go in all directions with 

 equal ease. But absolute uniformity does not exist in nature. 

 The openings in rocks are never of uniform size ; they are 

 never equally distributed. Suppose half way down the slope 



Fig. 6. 



there is a vertical opening of unusual size transverse to the plane 

 of the chart (Fig. 6), and another similar opening below the 

 valley. If you please, we will call them fissures. These fissures, 

 because large openings, will be fully utilized by the underground 

 water. We readily see that groundwater will enter the higher 

 fissure at many points and from various directions. Ordinarily 

 it will enter the upper part while it is still descending ; it will 



