70 GOLD AND TIN DEPOSITS OF SOUTHEKN APPALACHIANS. 
that a specimen selected for that purpose would have proved more satisfactory. No. 2 
indicates that gold is certainly present in the quartz vein at the Jones mine. While 23 
cents per ton is of course very little, it must be remembered that it is not -a negligible 
amount, since 50 to 60 cent ore has been mined in California and some of the ore now being 
milled at the Brewer mine is said to be not much above 50 cents. 
The fact, therefore, that some of these tourmaline-quartz veins, which are almost 
undoubtedly of magmatic origin— derived from the granite magma — carry gold is a strong 
argument in favor of their being an intermediate stage in one complete cycle, and fairly well 
establishes the relation of the gold deposits of the region to the granite. It may be noted 
here that the gold deposits of Dahlonega are believed by Mr. Lindgren to have a genetic 
relation to a granite similar to, if not actually the same as, that occurring in this region. 
In conclusion, it may be said that while the source of the solutions can not be definitely 
proved, the weight of evidence favors the view that the gold deposits represent the final 
products of the granite magma, the concentration of certain elements from an immense 
body of rock. The full geologic sequence is therefore doubtless as follows: 
1. Intrusion of granite. 
2. Intrusion of granitic or aplitic dikes causing the development of biotite and amphibole 
in their wall rocks. 
3. Intrusion of pegmatite dikes, some of which carry cassiterite, impregnate the sur- 
rounding rocks with tourmaline, and cause the development of biotite and other meta- 
morphic minerals in their walls. 
4. Formation of quartz veins carrying tourmaline, ilmenite, sulphides, etc., and, in some 
cases, gold, causing in their wall rocks the development of tourmaline, magnetite, biotite, 
garnet, ilmenite, and sulphides. 
5. Formation of quartz veins (and replacement deposits) carrying ilmenite, sulphides, 
and gold, and causing in the surrounding rocks the development of fluorite, biotite, sericite, 
ilmenite. sulphides, and gold. 
It is necessary to consider more fully at this point a subject to which reference has 
already been made — namely, the relation of some of the large replacement bodies to the 
diabase dikes which cut them. In former descriptions of the Haile mine it has repeatedly 
been stated that the ore bodies were caused by the dikes of diabase, which occur in their 
midst. The same has been said of the Colossus mine, where similar conditions exist, and 
as an explanation of the formation of ore at the Brewer mine it has been stated that a dia- 
base dike occurs close by. Particular attention was given to testing this hypothesis, 
especially at the Haile mine. The statements that the ores at this mine are richer in the 
vicinity of the dikes are frequent and fairly consistent. It is often stated, on the other 
hand, that the richest ore is not immediately surrounding the dike, but at a distance of 
several feet. This richness in the neighborhood of the dikes may he accounted for in four 
ways: 
1. The ore may be the result of the intrusion of diabase, as commonly stated. 
2. The deposition of the ores from the vein solutions may have been influenced by solu- 
tions from a different source that were present in the fissure later occupied by the dike. 
3. Secondary enrichment, which was possibly a factor in the present distribution of the 
gold, may have been especially effective along the fissures at the sides of the dikes. 
4. The unequal distribution of the gold may be in no way related to the dike or to the 
fissure occupied by it. 
These possibilities will be considered in order. 
1. If the diabase and the ore are genetically related, they came from the same source and 
through the same channel. 
Development work outside the main ore lenses indicates the presence of no more gold 
or other materials of the ore at the contact of or near the dike than is found away from it. 
Both in and outside of the ore bodies the only visible effect which the diabase has had on 
the surrounding rock is a slight induration extending an inch or two from the dike. Where 
