ransome.] LODES OF CANYON CREEK. 201 
by a, much longer tunnel 300 feet below it. This is a crosscut about 
2,200 feet in length, driven S. 15° W. It is furnished with a single 
well-laid track, and in October already connected with over 1,200 feet 
of drift, which length was being rapidly augmented. A view of the 
surface features of the Camp Bird mine and of the large lobe of 
"slide-rock" beneath which the main tunnel is run is shown in 
PL XIV. 
The country rock of the Camp Bird is the andesitic breccia of the 
San Juan formation. As this rock extends to the mouth of the gulch 
and some way down Canyon Creek, it is probably considerably over 
2,000 feet in thickness below the croppings of the lode. It thus insures 
practical uniformity of volcanic country rock to a rather unusual depth, 
and is so far favorable to regular and persistent ore bodies. 
Nearly all the ore produced under the present ownership has come 
from the level 300 feet above the new adit. The lode where inter- 
sected by this crosscut adit is a mere fracture, the thickness of a 
knife blade, accompanied by a few small quartz stringers on the 
footwall side. The fissure soon widens to the east and west, and the 
lode has an average width of 4 or 5 feet. When typically developed 
it is a sheeted zone in the rather fine San Juan breccia, made up of 
narrow stringers of gangue and ore alternating with sheets of country 
rock, and having fairly well-defined walls. The hanging (south) wall 
is the more regular, and a very thin seam of clay gouge shows that 
there has been slight movement along it since the lode was formed. 
Near the foot wall there is uniformly a streak of lead-silver ore, carry- 
ing galena and sphalerite. This is sometimes contiguous with and 
apparently an integral part of the main lode. At other times the two 
are separated by a thin sheet of country rock. The vein is unusually 
adherent to a somewhat irregular toot wall, which is often traversed 
by irregular quartz stringers, or may be brecciated and cemented by 
quartz. Although the lode is a sheeted zone, the country rock, out- 
side the recognized limits of the deposit, is not notably fissured. The 
foot- wall streak of galena ore has 1 >een pa rl ly 1 >recciated and recemented 
by stringers of white quartz. This later quartz is not to be distin- 
guished from the quartz of the auriferous portion of the lode and may 
be of the same period of deposition. The silver-lead foot-wall streak 
was the ore mined twenty years ago, before the high-grade ore lying 
alongside it was discovered. The richest ore occurs near the hanging 
wall, often directty against it, and the richest portion of the pay streak 
is indicated by dark, narrow, undulating lines of ore minerals. These 
lines define the course of small stringers, usually an inch or less in 
diameter, which are of later origin than the mass of the vein. The 
latter is a pale greenish-white mottled aggregate of quartz, fluorite, 
sericite, and calcite, thickly sprinkled with small crystals of pyrite, 
with some sphalerite, galena, and possibly other ore minerals in 
minute specks. It is probably in part altered country rock. The 
