20 ORE DEPOSITS OF TONOPAH, NEVADA. [bull. 219. 
pah" vein, and crosses Mizpali Hill in an east- west direction, showing 
a strong outcrop. This outcrop is cut off both to the east and to the 
west by heavy faults, so that it is adjoined on the east by therhyolite 
of Oddie Mountain and on the west by the later andesite. From the 
Mizpah vein a succession of branches depart, running chiefly in a 
southwestern direction from the eastern end of the outcrop, and each 
successive branch diverges more than its predecessor from the strike 
of the main vein, so that the whole group is like a section of the 
spokes of a wheel, the spokes uniting some distance east of the main 
shaft. The chief of these branches are known as the Burro No. 1, 
No. 2, No. 3, etc. They are strongest near the main vein, and those 
which diverge most from the strike of the latter are weaker than those 
which are more nearly parallel to it. The intersections of the branches 
with the main vein and with one another usually pitch to the east at 
a moderate angle. These easterly pitching intersections are signifi- 
cant, since they have the same general c~ur.se as certain shoots of 
especially rich ore in the same vein, and correspond also in direction 
to some post-mineral fracturing and faulting. The main vein has in 
general a steep northerly dip, which is locally overturned so as to dip 
steeply to the south. 
The Valley View mine shows a group of veins of the same general 
type as the Mizpah, but with minor differences. The main Valley 
View vein as exposed in the workings has, like the Mizpah vein, 
a northerly dip, but is very much flatter. It is very large, and the 
rich ore in it is unequally distributed, occurring in shoots or bunches. 
As the large vein approaches the surface it splits into several some- 
what smaller veins, which assume a nearly, or quite, vertical posi- 
tion. This vein group is in general very nearly parallel to the Miz- 
pah group; the linked character, forking and reuniting, is quite as 
well marked as in the Mizpah group; and there is some radiation in 
the strike of the veins, although not so much as in the former case. 
The Valley View veins are affected by post-mineral faulting, like the 
Mizpah vein. 
The Montana Tonopah group shows a strong main vein running 
cast and west and dipping north at a moderate angle. A number of 
lesser veins have been cut in the workings, and although development 
at the time of the writer's examination Was comparatively slight, it is 
probable that most of these veins will eventually unite with one 
another or with the trunk vein. The indications are that the branches 
lie mostly on the north side of the trunk vein and diverge in trend 
from it, opening out to the east. These branches as a rule dip more 
steeply than the main vein, and will, therefore, also tend to unite 
with it vertically. The Montana Tonopah veins are, like the others, 
displaced by considerable post-mineral faulting. 
In all these veins the union of two branches to form one is generally 
attended by corresponding enrichment, and, conversely, the place 
