CHAPTEE VI. 



GENESIS OF LEADVILLE DEPOSITS. 



The ore deposits of the region having been described in the foregoing 

 chapters, with as much detail as space allows, it remains to gather together 

 briefly the evidence upon which the general conclusions with regard to 

 their origin and manner of formation, given in Chapter I, have been ar- 

 rived at. 



Before entering upon the discussion of this evidence, however, I would 

 state that I do not claim that these conclusions are absolute or final, nor do 

 I wish to be considered as offering them as general theories applicable to 

 all ore deposits. They are those that seem to best accord with the facts 

 now at my command, and these facts have been presented carefully, con- 

 scientiously, and without bias in favor of any preconceived theory. Other 

 facts may come to light which may lead to a modification of these conclu- 

 sions, and I reserve the right to adopt such modifications wherever the 

 evidence afforded by further developments in this or any other district 

 which may come under my notice shall seem such as to require it. The 

 study of the underground structure of a mining district necessarily pre- 

 sents many problems which cannot be definitively solved until the entire 

 area has been explored; nevertheless, deductions may be made from ob- 

 served facts, and from analogy with facts gathered in other carefully studied 

 regions, which will justify a hypothetical forecast that may be of great 

 practical service to those engaged in mining, even should that forecast be 

 proved later to be incorrect in some of its details. 



In studying the genesis of the ore deposits of Leadville, one main 

 difficulty at the time that this work was carried on was their universally 

 oxidized condition, resulting from secondary alteration by surface waters, 



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