156 Mining Regions of Southern New Mexico. [ February, 
are of comparatively small dimensions, stand nearly vertical, and 
show ore of a higher grade than the bulk of the main deposit 
It is a noticeable feature that no such veins have been found in 
the shales (c) underlying the foot-wall strata (d). Mineralogi- 
cally the ore of this locality must be considered as an aggregate 
of manganese and ferric oxides with but a slight admixture of 
gangue rocks. The silver is distributed throughout the mass 
ore in the form of cerargyrite (chloride), embolite (chloro-bro- 
mide) and a small percentage of argentite (sulphide). It is well 
known how the first two of these minerals were struck in large: 
quantities, of great purity, at various points in the ore-bed, far- 
nishing ore worth from five to ten dollars a pound. 
Near the crest of the first ridge the ore-bed has been removed 
by erosion, together with the overlying strata. On its easterly 
slope mining is essentially reduced to open quarry work, because | 
the hanging-wall (e) has been broken away at many places. Fore 
lowing the dip of enclosing strata, the ore sinks out of sight un 
der the second hog-back, directly east of the new camp. Along. 
the strike of the strata, 7. e., approximately north and south, the 
ore-bed either crops out or fas been struck in its normal position 
for a distance of more than 2000 feet, always bearing the same 
relations to adjoining strata. Towards the east it may extend 
indefinitely. No disturbing action has turned up the strata in 
that direction, so that the point could be demonstrated. Defining, : 
then, in a few words this occurrence, we find it to be: a mangatr 
ese and iron bed, conformably interstratified with carboniferous 
limestones, impregnated and associated with specific pe 
minerals. 
Beyond the establishment of this ore-body as a well- define : 
stratum, a highly interesting question is propounded in the exist oe 
ence of the transverse veins and seams above alluded to. Primar, 
rily we may take for granted the formation of a manganese ari 
iron bed, synchronously with the deposition of the entire | is 
mentary series. From evidence obtained in the vicinity of 
Valley, it appears that the trachyte flowed from the more fer : 
regions in an easterly direction. Subsequent disturbances and 
erosion affected the removal of the larger portion of the volcanic | 
material. Monument peak, in close proximity to the mines, ci) 
remnant of a flow from the westward. There seems no room 10 
doubt but that the ridges now containing the ore-bed were at one 
