218 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
Mr. T. E. Schwarz, for several years superintendent of this mine, 
has kindly furnished some important data in regard to the ore bodies. 
The ore in the Yankee Girl shoot, down to No. 1 level, a distance of 
75 feet, was chiefly galena, and averaged 77 ounces of silver and 3(> 
per cent of lead. From No. 1 level to No. 2 level, 80 feet, it averaged 
242 ounces of silver and 29 per cent of copper, lead not being given. 
The galena, however, was disappearing, and the characteristic min- 
eral from the second to the sixth levels was stromeyerite, associated 
with chalcopyrite, pyrite, and occasional occurrences of argentite and 
other rich silver ores, some of which carried bismuth. Similar changes 
took place in the Orphan Boy shoot, although the galena continued 
to greater depth. On the sixth level (432 feet deep) these two ore 
shoots came together, a straight drift in continuous ore connecting 
them. A few feet below this occurred a heavy, strong, nearly hori- 
zontal seam or slip carrying much "talcy" material. 
The rich ores of the Yankee Girl disappeared at this seam, no stromeyerite or 
other distinctive rich silver mineral being found below it. The main Yankee Girl 
ore shoot continued down through it without perceptible change of position, and 
was large and strong from No. 6 to No. 8 levels. The character of the ore changed, 
however, and "peacock copper,'' with pyrite and chalcopyrite became its constitu- 
ents. Bornite I took to be the principal ore for large masses. To show grade of 
selected ore produced from richest stopes. I may. note a shipment of 10 tons which 
carried 3,270 ounces of silver and 29 per cent of copper. A smaller lot of 7,360 
pounds returned 5,301 ounces of silver and 28.75 per cent of copper. 1 
Speaking from memory, Mr. Schwarz believes that the ore in tin 
bottom levels of the Yankee Girl was low grade and carried mor< 
P3 7 rite than above. 
These various descriptions of the ore bodies are given at son* 
length, since they are not in perfect agreement on all points, and yel 
they furnish cumulative evidence of the truth of certain important 
features. 
Mr. Schwarz 2 has also published a description of the ore bodies of 
which the Yankee Girl is the type. He says, in part: 
The ore occurs in "chimneys," so called, having in some cases an elliptical or 
circular cross section, but more generally long in proportion to their width. The 
greatest length of ore body so far observed has been about CO feet. 
The immediate envelope of the ore chimneys is "quartz," which is sometimes of 
considerable extent, while the whole is inclosed in an area of greater or less extent 
of andesit^. 
The andesite is metamorphosed in proportion to its nearness to the ore chimney, 
showing more kaolin and quartz and less of its original structure. It thus merges 
into a fine-grained brown or grayish quartz, sometimes very hard and flinty, an( 
again quite porous. In depth the quartz matrix becomes less characteristic. 
1 Personal letter from Mr. Schwarz. It is not clear, in view of the figures just given by Mr, 
Schwarz, just what he means by saying that no rich silver ore occurred, below No. 6 level. Ht 
probably refers merely to the mineralogical change in the ere from stromeyerite to bornite, or 
he may mean that these high-grade lots came from above level (5. The high copper percentage 
however, would not indicate this. 
2 Notes on the ore occurrences of the Red Mountain district: Proc. Colo. Sci. Soc, Vol. Ill, 
1888, pp. 77-85. 
