eckei,.] GOLD AND PYRITE OF DAHLONEGA DISTRICT, GA. 61 
consequence the relations of the ore deposits to the country rock can 
be studied to better advantage than was possible at that date. The 
most interesting feature developed by the recent work has been in 
relation to the position of the ore deposits. The writer believes it can 
now be accepted as proved that in the large majority of mines in the 
Dahlonega district the more profitable and continuous veins occur 
along the contact between the mica-schists and an igneous rock, the 
igneous rock being either a granite or a sheared diorite. This occur- 
rence was first pointed out to the writer by Gen. A. J. Warner, as 
occurring in the mines on Findley Ridge, and was, on further exam- 
ination, found to be the common type of occurrence throughout the 
entire district. There are, it is true, exceptions to this rule, but they 
are not numerous. In a few cases (Betz mine, etc.) a body of schist, 
not in the immediate vicinity of an igneous rock, is so cut by minute 
gold-bearing quartz veins as to permit the entire mass to be profitably 
mined, while in other instances, as on the Walker property, a small 
but rich gold-quartz vein occurs entirely within the schists. 
The genetic relationships existing between the ore deposits and the 
igneous rock, in the two cases presented (granite and diorite), are of 
very different character. The diorite, as noted earlier in this paper, 
was injected into the schists at a much earlier period than that dur- 
ing which the ore deposits were formed. This is proved by the fact 
that this diorite has been crushed and sheared to such an extent that 
it now appears as a hornblende-schist, the schistosity of which con- 
forms to. that of the normal mica-schists of the region; Avhile the gold- 
bearing veins cut both diorites and mica-schists, and have suffered 
very little from either folding or faulting. The fact that many promi- 
nent gold-bearing veins occur along the contact between the diorite 
and the mica-schists is not due, therefore, to any direct action of the 
diorite considered as an igneous rock, but to the facts (a) that fissures 
are most likely to be formed along the contact between two forma- 
tions differing in hardness and rigidity, and (b) that such fissures, 
minute at first, may have been enlarged by the solution of the 
relatively unstable diorite. 
With regard to those deposits which occur along the contact be- 
tween granite and mica-schist the case is somewhat different. Here 
the intrusion of the granite may possibly have some direct genetic 
connection with the formation of the ore deposits. As noted above, 
the granite is younger than the diorite, cutting the latter at several 
points in the area; it shows little or no banding and has been rela- 
tively little folded. At several points the granite shows slight band- 
ing; at other points minor faults occur within it. Rock movements 
have evidently occurred in the region since the intrusion of the 
granite, but such movements have been slight compared to those 
which occurred in the interval between the intrusion of the diorite 
ind the intrusion of the granite, as is evidenced by the relative amount 
)f shearing shown by the two rocks. 
