88 GOLD AND TIN DEPOSITS OF SOUTHERN APPALACHIANS. 
tuffs. Fragments of feldspar — microcline, micro perthite, and plagioclase — and of brownish 
biotite are readily discernible in most of the microscopic sections of the rocks. The folia- 
tion of these schists, which appears in all cases to represent original bedding, strikes N. 55° 
to 65° E. and dips northwest at an angle of almost 90°. These schists have been silicified 
along certain bands which appear to represent shear zones. Where unoxidized, the resulting 
siliceous rock is dense and bluish, with lustrous cleavage faces almost identical with the 
Haile ore except that at the Colossus the banding is generally better preserved. A pro- 
nounced jointing has taken place, evidently since the silicification of the schists. These 
joints dip 80° to 90° SW. and strike about N. 35° W. Along these principal joints several 
dikes of diabase of similar character to that at the Haile mine have been intruded. They 
range in width from 5 to 8 feet. These joints and dikes often fault the ore body. One dike 
to the northeast of the principal mine workings is said to displace the vein 300 feet laterally. 
It is said that in the case of all these faults the northeastern side is thrown to the northwest. 
The "Monroe" beds, which are known to exist a few miles to the northeast, have evidently 
been eroded away in the immediate vicinity of the Colossus mine and certainly have no 
connection with the ore. 
This mine is another excellent example of the replacement deposits of this region. The 
ore is decidedly similar to the Haile ore. It is hard, blue, siliceous rock, usually with decided 
fissility or cleavage, and contains pyrite. As at the Haile mine, ore is limited to the silici- 
fied portions of the schists. Small quartz stringers, usually parallel to the foliation, give 
the impression of almost complete replacement by silica of the rock adjoining narrow 
fractures. Pyrite is a little more abundant near these stringers than elsewhere. The 
zones of most intense silicification in general constitute the best ore. They exhibit a decided 
sheeting parallel to the original foliation and doubtless owe their existence to the fact that 
the ore-bearing solutions found readiest channels along sheeted zones. Oxidation is also 
more advanced along these sheeted zones than elsewhere, owing, without doubt, to the 
more easy penetration of solutions which they allow. Pyrite is less abundant and more 
evenly distributed through the ore than at the Haile mine and no molybdenite has been 
seen. 
The condition of most of the gold is a matter not definitely established. It is said at 
the mine that the greater part of the gold is free and also that there is very little pyrite 
present. The fact that mining was carried on fully 200 feet below the water level when 
amalgamation was the only means of extraction employed would seem to strengthen this 
statement. The writer saw numerous specimens containing free gold, but all of them had 
suffered oxidation and in all the gold had the appearance of having been derived from 
pyrite. While it is true that pyrite is not abundant, it is present in tiny grains all through 
the ore, in amount ample to contain all the gold which the assays show. A possible explana- 
tion of the presence of free gold below the water line may be found in an occurrence near 
the bottom of the Pansy shaft. Joints and crevices along which water from the sur- 
face travels with more or less ease show the effects of oxidation; the adjoining rock is 
stained brown or red and a red slime oozes down the walls. The ore is usually better near 
these places than elsewhere. Away from visible fractures of any kind, the hard, unstained 
blue rock is often found to be porous, containing many minute cavities which correspond 
in form to pyrite crystals. Some of these cavities are partially filled with a light-colored 
crystalline substance which proves to be at least in large part ferrous carbonate. It is 
evident that some kind of solution, which probably means some kind of oxidation, has 
attacked the pyrite. It is equally evident that waters carrying dissolved oxygen, like the 
ordinary surface waters, have not been active. It is possible that the pyrite has been 
oxidized and converted into a sulphate by sulphuric acid, or ferric sulphate, or both. Such 
a reaction may have necessitated the liberation of free sulphur or of sulphur dioxide, 
although evidence of neither of these was seen. It was impossible to decide 1 how wide- 
spread this phenomenon has been, and free gold has not been detected in the cavities 
originally occupied by the pyrite; but it is possible that gold could in this way be liberated 
from the inclosing sulphide and form a free-milling ore below the limit of ordinary oxidation. 
