170 
AMERICAN GEOLOGY. 
found upon the surface. The slates of Tennessee, Virginia, 
and North Carolina abound in this species of iron ore; but so 
far as discoveries have yet been made, the mounds of oxide of 
iron do not overlay copper, except at Ducktown. 
A vein three miles south from the Congdon mine, and just 
within the limits of Georgia, exhibits the general original 
form of the lodes in the vicinity of Ducktown (fig. 42). This 
vein was discovered by follow¬ 
ing the indications furnished 
by the gossan. Upon the sur¬ 
face this substance was ob¬ 
served to be rather common at 
the locality referred to, and 
selecting a place which repre¬ 
sented the center of disper¬ 
sion, a shaft was sunk almost 
at random. When the earth 
was removed from the rock a 
narrow crevice was observed, 
which contained the gossan; 
and on following it down 
twenty-five feet, the crevice 
expanded into a large pipe vein of the form presented in the 
figure. This peculiar lode was struck five feet higher on the 
north side of the shaft than upon the south. This pipe vein 
penetrates the rock obliquely. The black oxide of copper and 
gossan occupy the same relative position as at the Congdon 
vein. The Congdon mine was originally a larger pattern of 
the same kind of vein as the Georgia mine. At the deepest 
part of the shaft this is five feet wide, and a ton of black oxide 
was taken out of it. 
The Georgia mine is noticed for the purpose of illustrating 
the peculiar form of the pipe vein, which seems to constitute 
an interesting feature in the Ducktown mining district. 
Fig. 42. 
