376 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
vertical, and is opened for 250 feet north and south of the shaft, between levels 
4 and 8. A westerly branch, not known on the upper levels, then appears; it passes 
a few feet west of the shaft, and has been 
developed on levels 9, 10, 11, and 12. 
Between the two lies a shorter branch, 
chiefly known from levels 8 and 9. The 
two main branches seem to split about 250 
feet south of the shaft. Beyond the junc¬ 
tion, 300 feet north of the shaft, the Last 
Dollar vein has been developed only on 
levels 5 and 11. It is poorly defined, some¬ 
times showing only as a number of tight 
slips in the rock, and has a tendency to turn 
off to the west. At a small stope 400 feet 
north of the shaft, on level 5, the vein shows 
as a seam of fluorite 2 to 5 inches thick, with 
several subordinate parallel cracks. On 
level 11, 550 feet north of the shaft, a frac¬ 
tured zone, which probably corresponds to 
the main vein, contains fluorite and dolomite 
carbonates with scattered values. One hun¬ 
dred and fifty feet east of this point the 
extreme workings on this level have opened 
a narrow seam, rich in spots, with fluorite 
and tetrahedrite. 
On the Last Dollar veins the ore consists 
chiefly of tellurides, with dolomite gangue, 
also some fluorite and quartz, the whole 
forming a sheeted zone 3 or 4 feet wide. 
Open spaces are not common. Tetrahe¬ 
drite is reported from a winze on level 12, 
on the main vein, but elsewhere seems 
largely confined to cross veins. 
The cross veins are at least four in num¬ 
ber. The first and most important crosses 
the shaft at about level 6 and is traceable 
from the surface down to the bottom level. 
It contains much fluorite in places, as well 
as vug holes along a central seam. On level 
12 the second or south cross vein contains 
open spaces as much as 2 feet wide and 12 
feet long. Secondary action by silica solu- 
Fig. 43.—Vein system of Last Dollar mine, on levels 5, tions, resulting ill pseudomorpllS of quartz 
after dolomite and celestite, is common. 
Massive pyrite, with zinc blende, tetrahedrite, and molybdenite, commonly occurs on 
the cross veins, but the values do not extend more than 40 feet from the main vein. 
