RAXSOME.] 
STRUCTURES OF THE LODES. 
69 
crops, notably those which stand out on the steep slopes of Dome 
Peak, north of Howardsville, and in particular near the head of Mill 
Creek, west of Chattanooga, where the Silver Crown lode is beauti- 
fully exposed in the bed of the stream, and the details of its structure 
may be seen through the clear water. Fig. 4 is a sketch of the lode 
is seen at the bottom of a clear pool in the creek. In minor develop- 
ment it is to be seen in nearly every fissure deposit in the quadrangle. 
The most regular of the veins will sometimes locally split up into a 
stringer lode, particularly where the fissure is seen about to die out 
in the country rock. 
Breccia lodes— thai is, Lodes in which the ore and gangue originally 
Qlled the spaces in a /one of brecciated country rock, do not appear 
:o be common. The only deposil 
seen which would appear to be 
jharacterized chiefly by this struct- 
ure is thai of the Silver Queen 
nine on Bear Creek, near the north- 
ern edge of the quadrangle. Here 
lie pay streak, from 3 to 6 feel 
iide, Lies in a brecciated /one about 
2 feel wide in t Lie San Juan forma- 
ion. Judging from I he materials 
jfeen on their dumps, the Polar Star 
ind Red ('loud Lodes also were in 
oart deposited in breccia /.ones. 
To a certain extenl the lodes as 
>riginally formed have had their 
ftructure modified by later move- 
bents, resulting in fractures in the 
ire already deposited, followed by 
b secondary veining, usually of 
juartx. It could not be proved 
hat this process has exerted any 
mporiant influence upon the ore. 
litre small and relatively barren 
/foot 
Fig. 5.— Cross section of the Japan lode, 
showing structure produced by successive 
openings of the original fissure, a, country 
rock; b, quartz; c, ore. 
As a rule the secondary stringers 
In the Tom Moore lode the later 
t ringers carry a little free copper, but the amount is insignificant 
rom a commercial point of view. In the Polar Star and Red Cloud 
nines an earlier deposition of quartz carrying pyrite was certainty 
fcecciated and followed by renewed veining. But there was no means 
I determining in L899 to which period of deposition the ore of these 
nines belonged. The Japan lode, a section of which is shown in fig. 
, appears to have been formed by successive openings of the original 
issure. The main ore streaLi of banded galena and sphalerite ore was 
rst deposited. Later, nearly barren white quartz, with well-marked 
oml) structure, was deposited in fresh openings on each side of the 
riginal vein. 
