Mineral Deposits of Eastern California .— Fairbanks. 149 
profitable below 700 feet, where it broke up into stringers with 
a heavy seam of clay. The greatest depth reached in the 
mines of Bodie is 1,200 feet, but no profitable ore was found, 
the biggest veins being replaced by fractured rock and clay. 
According to Whiting, native silver was found in seams of 
the rock adjoining some of the veins, while pyrites and silver 
ores occur in small amounts. The ore from this district is all 
free milling, even at the greatest depths worked. 
It is evident that since the solfataric action took place along 
this crushed zone but little erosion has occurred and the su¬ 
perficial character of the ores is for that reason all the more 
remarkable. Although no such depth has been reached in the 
other gold mines of eastern California there is no reason to 
believe that they differ from the common type of the rest of 
the state. The comb structure of the quartz and the pro¬ 
nounced banding of a large number of the veins of this dis¬ 
trict suggest strongly the presence of more or less open fis¬ 
sures during ore deposition. 
Argentiferous Galena. 
Important deposits of argentiferous galena have been 
worked at Cerro Gordo, Darwin and Modock in Inyo county. 
The ore occurs generally in limestone in chamber form, al¬ 
though occasionally it assumes a vein-like character. The 
Modock mines on the eastern slope of the Argus range illus¬ 
trate well the characteristic manner of occurrence. A great 
thickness of limestone forms the eastern slope of the Argus 
range between Darwin and Modock, and in many places it has 
been more or less mineralized, as shown by the bright yellow 
and red surface tints. The Modock mines are situated on a 
hill one half mile in diameter terminating a spur of the range. 
The central portion of the hill is filled with chamber deposits 
of galena rich in silver. These are scattered in such an irreg¬ 
ular manner that no systematic method of development can 
be undertaken. Some are found by following minute stringers 
of ore or slightly mineralized country rock, while others are 
located by chance. The hill has been opened to a depth of 
1,150 feet, at which level the richest ore was found. 
The Defiance mine at Darwin consists of a series of irregu¬ 
lar chambers between granite and calciferous quartzite. Much 
iron oxide is present in addition to the galena. Considerable 
