REDINGTON MINE. 285 



ing the New Almaden and the New Idria. The ore found at the surface 

 was the superior jjortion of an immense, irregular ore body, wliicli con- 

 tained far the hirger portion of all the ore which the mine has hitherto 

 yielded ; but downward continuations of this body of a much more reo-idar 

 character have been traced for several hundred feet. This cliange in the 

 torm of the deposit is an extremely interesting and important feature of the 

 occurrence. 



The rocks immediately inclosing the Redington mine are highly meta- 

 morphic and consist largely of serpentine, which is accompanied by sili- 

 ceous rocks and shales, as well as by a great amount of dark, impure opal. 

 Close to the deposit, however, and in contact with it at one point, is a con- 

 siderable area of unaltered sandstone and shale. The strike of the deposit 

 is also the trend of the contact. The metamorphic rocks surrounding the 

 ore are far too much disturbed and altered to allow of any elucidation of 

 their stratigraphical position. 



In the upper and richer portion of this mine a large part of the mei-- 

 cury was in the form of metacinnabarite or black sulphide, whicli Dr. G. E. 

 Moore first described from this locality. Metacinnabarite, as already men- 

 tioned, existed abundantly at the Reed mine. Mr. Goodyear also observed 

 it at the Baker mine, between Knoxville and Lower Lake. It was found in 

 large quantities at New Idria, and I have in Chapter II called attention to 

 its occurrence in New Zealand, Mexico, and Rhenish Bavaria. So entirely 

 had the accessible portions of the upper levels of the Redington mine been 

 worked out at the time of my visit that I w\as unable to find any of this 

 ore in place. Specimens show that it was accompanied by opal and mar- 

 casite and that it was in some cases coated with cinnabar, as if in process 

 of conversion. It contains some iron. Dr. Moore's metacinnabarite was 

 amorphous, but according to Mr. Goodyear it also occurred in a crystalline 

 state. Dr. E. F. Durand describes crystals of this mineral which he regards 

 as orthorhombic.^ Onofrite has been reported from the Redington, but 

 there is little doubt tlmt the mineral su^iposed to be onofrite was in fact 

 metacinnabarite. I was informed that more or less cinnabar always accom- 

 panied the black ore. The two were certainh' mingled at New Idria. 



' Troc. California Acad. Nat. Sci., vol. 4, 1872, p. 2ia. 



