MINES OF BULL HILL. 
377 
On level 12 a strong cross vein is cut 125 feet south of the shaft, being probably 
the same that appears on levels 5 and 6. Just west of the main vein this intersects 
a number of short veins trending a little more northwesterly than the main vein. 
This southerly cross vein has been followed out to the side line of the claim, but 
the values soon decrease, though pyrite and zinc blende still occur in its seams. On 
some of the levels the cross veins south of the shaft are not well developed. 
Aside from some small ore bodies on levels 5 and 11, north of the shaft, the 
principal pay shoots occur at the intersections of the main vein with the first and 
second cross veins. The shoot at the main shaft has been followed 1,200 feet 
down; on the various levels it is up to 250 feet long along the main vein, and pay 
extends out on the cross veins for a distance of 40 feet at most on both sides. 
On the bottom level ore is said to extend for 180 feet north and 240 feet south of 
the shaft, establishing in fact a connection between the shoots on the north and 
south cross veins. Ore has been found also on various upper levels at the inter¬ 
section of the cross veins south of the shaft, but it does not form as well defined a 
shoot as that near the main shaft. 
In the upper three levels, now inaccessible, the main shoot lies just south of 
the shaft and at the intersection of the cross vein with a vein of the Modoc system, 
between the two branches of the Last Dollar vein. From levels 4 to 8 it jumped 
across to the intersection with the easterly of the Last Dollar veins, while from 
levels 8 to 12 it was transferred to the intersection with the westerly branch of 
that vein system. 
DETAILS OF THE MODOC SYSTEM. 
The Modoc veins are at least three in number and lie in the general continua¬ 
tion of the Last Dollar veins, but have a more decided westerly dip of 75°. The 
easternmost is opened on level 5 at the south end line of the claim, but is here , 
unprofitable. It is the same as No. 2 vein in the Modoc mine, on which pay ore 
occurs. A central vein, the same as No. 1 or the principal vein in the Modoc mine, 
cropped on the surface for 400 feet and is opened by the three incline shafts A, B, 
and 0, the second being the deepest and extending to level 6. This vein contained, 
between the surface and level 3, an ore shoot of fair proportions, which below level 
3 becomes smaller and shows a tendency to pitch south. Between levels 5 and 6 
the ore contained much copper and silver, indicating a partly oxidized tetrahedrite. 
The vein shows large vugs in a central seam, filled with loose material and coated 
with quartz and dolomite. Alunite, a secondary mineral, fills the medial seam in 
places. 
The developments on level 10, the next one below level 6 in this part of the 
mine and the deepest at present, have shown the existence of rich ore with some 
tetrahedrite on this narrow vein. A third of the Modoc vein system has been 
opened in the extreme southwest corner of the claim. 
