CHAPTER XrV. 



DISCUSSION OF THE ORE DEPOSITS. 



Purpose of the chapter. — Tlic varlous ciiiiiabar deposits of the Pacific slope 

 have many features in common; indeed, it does not appear to me practi- 

 cable to divide them into two or more groups. Each mine, however, affords 

 special facilities for the study of particular characteristics and comparisons 

 are essential. This chapter will he devoted to comparative descriptions of 

 the deposits and I shall also endeavor to include in it such information with 

 reference to the occurrences as seems likely to be welcome to readers who 

 desire a general knowledge of the quicksilver deposits of the Pacific slope 

 rather than full particnlars of any one property. It will include studies 

 of the ores, gangue minerals, and inclosing rocks, a discussion of the place 

 which these ore bodies occupy in the general classification of deposits, and 

 remarks on the relations which they bear to metamorphic areas and to 

 volcanic rocks. The origin of the ores and the manner in which they were 

 dissolved and precipitated will be discussed in separate chapters. 



MINERALOGICAL CHAEACTER OF THE DEPOSITS. 



Ores. — Quicksilver is obtained on the Pacific slope from four minerals, 

 cinnabar, metacinnabarite, native quicksilver, and tiemannite (mercuric sel- 

 enide). The last occurs in quantity only near Marysville, Piute County, 

 Utah. Reduction works are in operation, and, it is said, at a profit. Cin- 

 nabar is the chief ore in the United States, as it is elsewhere, and only a 

 small portion of the metal is obtained from metacinnabarite or in the native 

 state. In the Redington, Reed, and New Idria mines, however, large quan- 

 tities of metacinnabarite were obtained from the higlier levels, but large 

 masses of this ore have not been seen in place during the present investiga- 



387 



