144 The American Geologist. March, 1896". 
THE MINERAL DEPOSITS OF EASTERN 
CALIFORNIA. 
Bj Harold W. Fairbanks, Berkeley, Cal. 
Introduction. 
The portion of California lying east of the crest of the Si- 
erra Nevadas has a mineral character which in many respects 
is quite unlike that of the rest of the state. Very little has 
been published about the ore deposits occurring here, although 
they are quite important economically and strikingly interest- 
ing from a mineral ogical point of view. On that account it 
has seemed that the following observations and discussion 
may be of some value. They are based on the examination of 
all the important mining districts between northern San Ber- 
nardino and Alpine counties. The area is bordered on the 
west by the Sierra Nevada mountains and is traversed in a 
general north and south direction by high and rugged ranges 
betw.een which lie the desert valleys. 
Types of Ore Deposits. 
The important ore deposits can be divided into two classes: 
(1) gold, (2) silver and lead. Of the silver ores two distinct 
classes may be considered: (a) argentiferous galena, gener- 
ally in the form of chamber deposits; (b) silver bearing sul- 
phides of antimony, arsenic and copper, occurring in well de- 
fined veins with a gangue of quartz. 
As a rule each of these classes of ores is strongly marked in 
its manner of occurrence, although there are important excep- 
tions. Almost all the gold deposits contain silver in appreci- 
able quantity and at times the value of the two metals is 
nearly equal. The important silver deposits on the contrary 
contain very little gold. 
Distribution and Geologic Relations of the Gold Ores. 
.Commencing in the southern portion of the area in question 
the important gold districts will be briefly described for the 
purpose of illustrating the exceedingly varied conditions under 
which that metal occurs. 
Near Post Office springs in the Panamint range gold is 
found in quartz veins inclosed in limestone. This rock, ex- 
posed in immense cliffs on the south side of the canon, has 
been folded in a syncline with slates below and on the sides. 
Much of the limestone is penetrated b}- minute branching 
