BATTLE MOUNTAIN MINES, WEST GROUP, AND OUTLYING PROSPECTS. 491 
movement of the walls, but the Cashen fault is characterized by the presence of more 
or less crushed and decomposed country rock or gouge. This material is sometimes 
4 or 5 feet in width. The net displacement effected by this movement, which may 
have been oscillatory, does not appear to have been great, as the fissures containing 
ore on the northwest side of the Cashen fault can in some cases be followed on its 
southeast side and show no appreciable offsetting at the lines of intersection, and 
the Montana dike is not noticeably offset where crossed by the Cashen fault on level 
7. As most of the lode fissures meet the Cashen fault at an oblique angle, however, 
the throw of the Cashen fault, assuming it to be later than the formation of the other 
fissures, is not readily detected. On the other hand, the fault may be older than the 
fissures that cross it. No decisive structural evidence bearing on this question was 
discovered, though the occurrence of the ores affords, as will presently be seen, some 
ground for thinking this explanation the true one. Its acceptance leads to certain 
corollaries in the shape of suggestive hypotheses as to the source and direction of 
movement of the ore-bearing solutions or gases. 
FORM AND STRUCTURE OF THE ORE BODIES. 
With the exception of some small bodies of ore stoped above level 6 near the 
Providence shaft, in the southern part of the mine, all the ore bodies lie in the 
northern half of the property. This productive ground extends from a point about 
300 feet south of the main shaft northward to the Dead Pine line—a distance of 
about 900 feet. The Cashen fault is the dividing plane between the generally 
productive and generally nonproductive territory. On the northwest or hanging- 
wall side of this fissure zone lie all of the productive portions of the Dorothy, Coin, 
Spur, No. 3, and Montana lodes. The ore bodies are without exception typical 
lodes determined by relatively narrow individual zones of sheeting or by the coales¬ 
cence of such narrow zones into pay shoots of considerable local width. 
The Dorothy lode, as seen on levels 9, 10, and 11, is a distinct sheeted zone in 
granite, usually from 3 to 4 feet wide, but without regular or persistent walls. There 
are usually two fairly regular narrow cracks or fissures which contain the bulk of the 
ore, the rest of the lode being made up of less regular fractures containing relatively 
little value. The stopes rarely exceed 4 feet in width, though in one or two cases 
little flat seams of ore have been followed for a few feet into the east wall. A 
narrow phonolite dike usually accompanies the lode, although the two are not 
always coincident. When the fissure zone does actually follow the dike the ore is of 
lower grade than when the lode is wholly in the graniter. The stopes extend only a 
short distance above level 9, the Assuring becoming irregular and indistinct as it is 
followed upward. On level 8 the Dorothy has not been clearly identified, though it 
may be represented by some indistinct Assuring about 50 feet east of the shaft. 
Toward the north the pay shoot usually comes to an end with the appearance of the 
phonolite dike in the Assure zone, a diminution of the Assuring, and a gradual 
decrease in the value of the ore. The Assuring also becomes less pronounced and 
the ore of lower grade near the main shaft. 
The Coin lode has been stoped almost continuously from the surface to level 9 
and between the main shaft and the Dead Pine line. This pay shoot seems to have 
