226 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
with a maximum width of 37 feet. But it was chiefly low-grade pyrite 
containing occasional nodules of bornite and chalcopyrite, usually 
with some barite. Substantially identical ore was found on the thir- 
teenth level. 
Through the kindness of Mr. Bedford McNeill, of London, liquida- 
tor of the New Guston Company, the following notes, dated March 
13, 1900, were obtained from Capt. James K. Harvey, formerly super- 
intendent of the mine: 
Galena ore was most abundant in the superficial workings, it having been 
met with almost at surface, and continued down to the fourth level. The ore 
contained from 8 to 50 per cent lead; silver, 9 to 30 ounces; gold, trace per ton. 
At the third level chalcopyrite and chalcocite were discovered, and continued 
down to where the fault was encountered, a few feet underneath the floor of the 
seventh level. Contents of ore: Copper, 5 to 15 per cent; silver. 25 to 700 ounces; gold, 
0.1 to 3 ounces per ton. A few cars were shipped (about 10 tons to the car) that 
ran over 1,200 ounces silver per ton, with a corresponding gold increase. 
From the third to the sixth level the ore occurred in the form of a chimney, its 
dimensions being from 12 to 15 feet in length and width at the third, fourth, and 
fifth levels, to 20 to 30 in length and width at and over the sixth level. Under- 
neath the sixth level the ore lengthened south approximately 200 feet, with a width 
of from 3 to 30 feet. 
Solid bodies of iron pyrites were discovered at the sixth level, and continued to 
the deeper workings. Contents: Silver, 4 to 20 ounces; copper, 1 to 3 per cent; gold, 
trace to 0.20 ounce per ton. 
Bornite was met with in quantity between the ninth and twelfth levels. Con 
tents: Copper, 18 to 25 per cent; silver, 60 to 175 ounces: gold, one-fourth to 1£ ounces 
per ton. Free gold was found occasionally with the bornite: that is to say, on the 
fluorspar ' associated with the bornite. No free gold was seen above the ninth 
level, or in any other instance. 
There was but little change in the volume or character of the water. It was 
destructive to pumps and column if they were not properly protected. 
Generally speaking, the inclosing porphyry was more decomposed where the 
ore was most compact and richest in its metallic contents. 
From the foregoing it appears that there was first an increase in 
the value of the ores down to the sixth or seventh level, and then a 
sudden falling off in value at the slip-plane below the seventh level. 
Below this occurred a diminution in the richness of the ore doAvn to 
the bottom of the mine. The characteristic ore minerals, in the order 
of the depth at which they prevailed, were galena, stromeyerite 
(pyrite?), bornite, chalcopyrite, and pyrite. But this succession is 
true only in general terms. Sudden and perplexing changes in the 
value and mineralogical composition of the ore occurred within the 
individual ore bodies at all levels, and the various minerals named 
overlapped in most complex fashion, although the bornite apparently 
had a definite upper limit and the stromeyerite a definite lower limit. 
Of all the ore minerals pyrite appears to have had the greatest ver- 
tical range, and it undoubtedly formed an increasing proportion of 
the ore with depth. The highest values in silver and gold were found 
in connection with high percentages of copper. 
1 Barite ? (F. L. R.) 
