CONCLUDING REMARKS. 277 



posits, and from this the unwisdom of the United States law in 

 the West, which is based on well-defined fissure veins. The only 

 practicable method is that a man should own all that is embraced 

 in his property lines, whether the ore body outcrops outside or not. 

 " A square location is the square thing " (Raymond). 



(2) The very general proximity of eruptive rocks in some form 

 to the ore bodies. Except in the case of iron, there are only a 

 few where these are not present, and apparently strong factors in 

 the circulations which formed the ore. The lead and zinc deposits 

 of eastern and western Missouri and the neighboring States, and 

 of Xew York and Virginia, are almost the only ones, and we are 

 justified in concluding that eruptive rocks are of great importance. 



(3) We know from the investigations of Sandberger and others 

 that the dark silicates of many rocks contain percentages of the 

 common metals. The choice is open whether to refer the ore to 

 original dissemination in these, and derive it by gradual concentra- 

 tion, probably at great depths, or to some indefinite unknown 

 source, which can only be described as " below." 



