92 SILVER-LEAD DEPOSITS OF EUREKA, NEVADA. 



conclusions. — The results of the chemical and physical examinations which 

 have been made of the rocks of Eureka have been rather negative than 

 positive as regards the source of the silver. They have shown what rocks 

 have not been the source of the ore more conclusively than they have 

 proved its origin. They seem, however, to point in but one direction, 

 namely, to some massive rock which has been decomposed by the solfa- 

 taric action attending the eruption of rhyolite. Through the decomposi- 

 tion of this i-ock metal-bearing solutions were formed which afterward pene- 

 trated the limestone and deposited the ore 



