94 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
AREAL DISTRIBUTION OF THE LODE ORES. 
The various minera logical and structural types of ore are not dis- 
tributed at random over the quadrangle, but a given portion of the 
area is often characterized by ore of a certain kind, differing from 
those which preponderate in other portions. These areal subdivisions 
are not sharply bounded, and it often happens that in a district in 
which most of the lodes contain a certain type of ore there will occur 
other ores which are more characteristic of some other district in the 
quadrangle. But, notwithstanding these transitions and exceptions, 
the localization of ore types is a striking feature of the region. 
The lodes traversing the mass of Sultan Mountain are quite com- 
monly filled with rather coarsely crystalline vein filling, carrying- 
galena, tetrahedrite, and chalcopyrite, with some sphalerite and pyrite, 
in a gangue of quartz and barite. Their chief value is in silver. The 
most productive of these lodes has been the North Star, which pro- 
duced an ore running about 40 per cent lead and 70 ounces of silver. 
This lode is in monzonite, but mineralogically similar ore is found in 
the King lode in Algonkian schists, said to carry about 0.1 ounce of 
gold, 55 ounces of silver, and 15 per cent of lead. The ore of the 
Empire group of veins is generally similar in character. 
Southeast of Silverton, in the vicinity of Deer Park, are numerous 
mineralized fissures cutting the schists and granites, and in soine 
cases the overlying San Juan breccia. These are occupied, as a rule, 
by quartz veins carrying pyrite, with a little galena, sphalerite, and 
chalcopyrite. They are prospected for gold, which occurs free in 
small pockets. Compared with most of the lodes in the quadrangle 
these veins are not heavily mineralized, and are not mined on an 
important scale. 
The lodes of Silver Lake Basin are characterized by coarse, massive 
structure and are heavily mineralized. Galena often exceeds all 
other constituents of the vein filling in amount, and lead is an impor- 
tant factor in the output. Sphalerite and chalcopyrite accompany 
the coarsely crystalline galena, and there is usually some pyrite 
present. The gangue is quartz, often containing chlorite. Tetra- 
hedrite occurs sporadically in many of these lodes, and barite was 
noted in the Royal Tiger workings. These are generally low-grade 
concentrating ores, averaging from $8 to $15 per ton. Free gold is 
rarely seen, but the gold tenor in some of the lodes of Group II (see 
p. 147) may rise to 2 or 3 ounces per ton. In the Silver Lake mine 
about half the value of the output is from the gold; the remainder 
being in silver, lead, and copper. The other mines contain less gold, 
and the Royal Tiger mine depends chiefly upon its lead. Most of the 
ore of Hazelton Mountain appears to have been of the general type 
just outlined. A thousand tons from the Aspen mine is said to have 
produced 110 ounces of silver per ton and 60 per cent lead, although 
the average tenor was somewhat less than this. An exception of the 
