122 THE GOLD DEPOSITS OF DAHLONEGA, GA. 
hydrochemical metamorphism. Calcite is present in compact or elongated aggregates, many 
of which include small parts of the quartz mosaic; it penetrates and is being penetrated 
by hornblende. The only mica present consists of small foils of chestnut-brown biotite 
embedded in the mosaic. 
Of the metallic minerals, magnetite is present in elongated masses, in places intergrown 
with pyrrhotite and chalcopyrite. There is no pyrite, but a considerable amount of 
pyrrhotite, usually intergrown with smaller grains of chalcopyrite. In many places these 
sulphides are inclosed in calcite or in hornblende. 
The most recent rock of the bed-rock series is a light-colored, coarse-grained granite, 
exposed at the Benning mine and at several points west of Yahoola Creek, in a westerly 
direction from Dahlonega. 
The relations of granite to the mica schists are very clearly exposed at the Benning mine, 
and the contact is illustrated in PI. VIII. The main contact, shown near the right of 
the plate, is somewhat indistinct for a distance of several feet, and this is due to the 
thorough injection of the schists near the contact plane by granitic magna, so that the rock 
here has the appearance of granite containing a great number of thin and dimly outlined 
streaks of schist. About 10 feet to the north of the contact the schist contains dikes of 
granite. These dikes, which are injected between the planes of schistosity, are bent and 
in some places contorted and have acquired a slight schistosity, as has also the main mass 
of the granite wherever exposed. 
The Benning granite is a white, coarse, granular, imperfectly schistose rock. The 
schistosity is apparent chiefly by the development of sericite on incipient planes. In 
sections perpendicular to the schistosit}^ the lenticular form of many of the grains indicates 
the pressure to which the rock has been subjected. Besides quartz and feldspar, the rock 
contains large flakes of biotite, 5 to 8 mm. in diameter, which, however, have mostly been 
converted into aggregates of muscovite. The microscope shows a granular but distinctly 
compressed rock. The large quartz grains are converted into aggregates of the same 
mineral. The feldspars, which consist of orthoclase and oligoclase in large grains, contain 
an abundance of straight muscovite foils, which have developed on the cleavage planes. 
They also contain zoisite and epidote in small crystals and grains. In places a great amount 
of recrystallized aggregates of quartz and feldspar mingled with muscovite have formed. 
A white, coarsely granular rock, collected from the Benning mine, proved to be almost 
wholly composed of albite in large anhedral or roughly square grains with thin twin lamellae. 
There is no other mineral present in this rock except a little muscovite in small foils and a 
little microperthite. This albite rock probably occurs as a dike near the granite contact. 
Although the grain of the schist is somewhat coarser than usual at the Benning contact, 
there is little evidence of contact metamorphism, except by the development of garnets 
and tourmaline in the schist, as described in more detail under the heading of the Benning 
mine (pp. 127-128). Whether the garnet is really of contact-metamorphic origin is not 
certain. The same doubt applies to the tourmaline, which is present in some schists at a 
considerable distance from granite contacts. 
PRODUCTION. 
The gold deposits of the Southern States have been known for one hundred years and 
were probably the earliest discovered and worked within the present area of the United 
States. Possibly some little placer mining had been carried on by the Indians in New 
Mexico prior to that time, but the important placer mines of that Territory were not dis- 
covered until 1828. Between 1799 and 1830 a small amount of gold was washed in the 
Carolinas. In 1828 gold was discovered near Dahlonega, and in 1830 the first deposit of 
gold from Georgia, amounting to $212,000, was made in the United States Mint. Shortly 
afterwards, in 1838, a branch mint was established, which, from 1838 to 1861, coined 
$6,115,569. The total production of gold and silver in Georgia, from the discovery to 1900, 
is between sixteen and seventeen million dollars, and of this amount the largest portion has 
been produced by the mines of Lumpkin County, in which Dahlonega is situated. The 
