spurr.] ORE DEPOSITS OF TONOPAH AND VICINITY, NEVADA. 87 
granite, and probably also in the limestone. Deeper exploration of 
these deposits has shown them to be almost entirely barren. In the 
main vein the quartz has continued in full strength downward, but 
the values have become insignificant. Similarly, a tunnel driven to 
the contact of granite and limestone, beneath the iron-ore deposits 
of the surface, shows nothing. These facts indicate that w r e have 
here an excellent example of the concentration of values near the 
surface, in the extreme upper part of the zone of oxidation, by the 
same surface waters that have operated to wear away the district and 
produce its topographic relief. 
At East Klondike the same limestone is cut into and surrounded 
by rhyolite, which has produced almost exactly the same contact phe- 
nomena as the granite at the Southern Klondike. Indeed, the two 
rocks are probably closely connected in point of composition and ori- 
gin. At East Klondike the contact of the rhyolite is marked by a 
broad belt of jasperoid, and similar belts are found farther away in 
the limestone, along lines of original easy circulation for waters. The 
chief vein near this contact consists largely of white quartz, but is 
evidently due to the same solutions which produced the dark-blue 
jasperoid. The vein and the metallic contents are exactly like the 
vein at Klondike. In some places high values have been taken out 
of the vein, but exploration has not been pushed far enough to show 
the character of the vein in depth. Along certain fracture systems, 
which are later than the vein and have broken and displaced it to 
some extent, there seems to be a segregation of higher values, accom- 
plished probably by more recent circulating surface waters. 
Gold Mountain district. — This lies nearty half way between Tonopah 
and Klondike and is in the stage of development. Gold Mountain is 
composed of rhyolite, both in solid flows and in consolidated tuffs and 
breccias. Through these rhyolites run strong and persistent veins of 
quartz and delicately colored chalcedony veins, sometimes containing 
pyrite. In some parts of some of these veins, especially in the oxi- 
dized portions, rich assays have been obtained. The mineralization is 
probably of a later date than that which has produced the ores at 
Tonopah, but may be of the same age as those at Klondike, although 
the ore deposits themselves are of a different character. 
Hennepah district. — The Hennepah district was at the time of the 
writer's visit very young and so little developed that not much could 
be seen. It lies nearly east of Tonopah, on the other side of a broad 
desert valley. The rocks of the district are volcanic, bearing a gen- 
eral resemblance to those at Tonopah. The veins also, of which two 
or three were observed, are of the same general character as the Tono- 
pah veins, although so far they have not been shown to have anything 
like the strength of the better class of veins in the older camp. 
