Doc. No. 9.] 89 



vein strikes north 25 degrees west, dipping east, with a power of four feet. 

 The investing rocks are talcose slates. 



KEYSTONE MINE. 



This mine is situated on the arroya leading into the Amadore; one mile 

 below Jones & Davis' mine ; it appears to be a parallel vein, half a mile 

 west of the line uniting the latter and the Spring Hill mine ; the ores par 

 take of all the general characters of the other two mines, and it is situated 

 25 feet above the level of the creek. The sett of Jones, Davis & Co. and 

 the Spring Hill are in the high hill east of the workings figured in the sketch 

 for the Keystone Mine. 



This vein strikes north 10 degrees west, diping 40 degrees east, with a 

 power of five feet ; the investing rocks are the graphic slate and chlorites, as 

 found in all the others in this neighborhood. 



EUREKA MINE, SUTTER, CALAVERAS COUNTY. 



This mine is located a short distance south of the town of S utter. The 

 company have one shaft, A, which is used for the whim by which the 

 ore is at present taken from the mine : a'cross cut, seen at D, in the ground 

 plan, was carried east 14U feet, intersecting the level, D, and main shaft, 

 from this the gallery, B, was carried south 135 feet, and subsequently the 

 lower level, C, was driven each way a distance of 230 feet. 



The mine is in active operation, and they are now driving an adit on 

 the east side of the hill, which will intersect their vein at an angle of 65 

 degrees to its line of strike, this will be 400 feet in length, and will afford 

 easy arid rapid communication with the reduction works. At the end of 

 the adit a tram-road is constructed 2800 feet, which connects with the 

 mill ; the gallery, B, 2, will be connected with the adit in the dotted line, 

 F, of the ground plan. 



The vein of this company is in chlorite, and has a strike north and 

 south, dipping east 55 degrees, with a power of five feet ; the vein has 

 a riband like appearance in masses, from small seams of graphic slate 

 running through it. The vein contains some arsenical ores, which are 

 highly auriferous. 





