766 C. R. VAN HISE 



shallow descending or lateral-moving waters. In other cases a 

 concentration by descending, lateral-moving waters alone is suffi- 

 cient to explain some ore deposits. It thus appears more clearly 

 than heretofore that an adequate view of ore deposits must not be 

 a descending-water theory, a lateral-secreting water theory, or an 

 ascending-water theory alone. While an individual ore deposit 

 may be produced by one of these processes, For many ore deposits 

 a satisfactory theory must be a descending, lateral-secreting, ascending, 

 descending, lateral-secreting theory. 



But there is no question in my mind that this theory is 

 still insufficient to fully explain many of the ore deposits. "No 

 knowledge is ever complete. We move step by step, carrying a 

 theory nearer and nearer completion. If, however, a theory be 

 based on good work, it usually will not prove to be false ; it will 

 be found to be incomplete. Sandberger was not wrong when he 

 said lateral secretion explained many things in reference to ore 

 deposits. He was wrong only when he excluded other factors. 

 He became unscientific when he carried his theory further than 

 his observations justified. While the theory here proposed is 

 believed to make an important advance, it will sooner or later be 

 found to be incomplete. I trust it will not be found to be false. 

 But the most that I can hope for it is that it is approximately 

 correct as far as it goes. 



It is believed that the principles which have been presented 

 lead to a new and natural classification of the ore deposits pro- 

 duced by underground water. As already noted, ore deposits 

 may be divided into three groups : (i) ores of igneous origin, 

 (2) ores which are the direct result of the processes of sedimen- 

 tation, and (3) ores which are deposited by underground water. 



Since the ores produced by igneous agencies and those pro- 

 duced by processes of sedimentation have not been considered 

 in this paper, a subdivision of these groups will not be attempted. 



Ores resulting from the work of groundwater, group (3) 

 above, may be divided into three main classes : 



[a) Ores which at the point of precipitation are deposited 

 by ascending waters alone. These ores are usually metallic or 



