444 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
and persistency. An excellent example of the more persistent and well-defined 
mineralized zones of sheeting is the No. 3 Hidden Treasure vein, as developed 
on the lower levels of the mine. Just above the 1,000-foot level this lode has a 
pay shoot about 500 feet in length, with an average width of about 12 feet. In 
the wider parts of the lode the Assuring is rather irregular. There are generally 
two or more nearly parallel and approximately vertical fissures, the outer ones 
being 6 to 10 feet apart. Between these the breccia is traversed by cracks running 
in all directions. The best ore occurs in the main vertical fissures, which are 
mere cracks in the rock, usually less than an inch in width, with a lining or vuggy 
filling of fluorite. There are no definite walls to the lode, the rock outside of the 
main vertical fissures being also irregularly jointed and carrying gold for varying 
distances from the main fissure zone. Where the stoping width of the lode, which 
is in some cases 15 feet, narrows to 10 feet or less the sheeting of the rock is more 
regular and more conspicuous. Such parts of the lode frequently exhibit in the 
neighborhood of 20 rather regularly spaced narrow parallel fissures with nearly 
vertical dips. Those sections of the lode in which such regular sheeting occurs 
are usually of higher grade than the wider and less regularly fractured portions. 
The other lodes in the breccia are all generally similar in structure to the 
Hidden Treasure lode. Some, such as the Lee veins, are narrower and often 
more sharply differentiated by their narrow-spaced vertical Assuring from the 
country rock. Definite vein walls, however, do not occur. Occasionally, as in the 
No. 1 Lee vein just above the 800-foot, level, the sheeted structure passes into a 
less regular form of reticulating fractures suggestive of what are commonly known 
♦ as stringer lodes. Other lodes, such as those composing the Captain group, are 
even less distinctly differentiated from the country rock than the Hidden Treasure 
lode. While vertical sheeting can sometimes be recognized in the medial portions of 
the Captain veins, the existence of the lode-is often marked merely by the irregular 
fracturing and jointing of the breccia. Such fracturing frequently involves all of 
the rock intervening between the indistinct medial planes of two or more of the 
Captain veins, and the fractured rock constitutes practically a single large ore body 
which is stoped as a whole. Such is the great stope 120 feet wide, on the Nos. 
3, 4, 5, and 6 Captain veins above the 350-foot level. In these large stopes it is 
often difficult or impossible to recognize an} 7 linear system of fissures such as might 
properly be called a lode. Practically all the minute fractures in the breccia con¬ 
tain telluride of gold, often invisible, but sometimes occurring in thin sheets of 
flat radial aggregates of sylvanite or calaverite along fissures a small fraction of 
an inch in width, and revealed by splitting the breccia along these veinlets. Such 
lodes pass gradually and indefinitely into the country rock, the limits of the ore 
body being determinable by assays alone. 
The lodes in the breccia are not all equally persistent, nor is persistency always 
commensurate with the size and importance of ore bodies. The largest ore body, 
about 500 feet in length, is found in the No. 3 Hidden Treasure vein. Tins lode, 
however, is not certainly known above the 600-foot level, whereas the smaller No. 4 
vein has been stoped almost continuously from the surface to the 1,000-foot level. 
In the Captain group of lodes the largest ore body is something less than 300 
feet in length, and most of those discovered are shorter than this. These lodes 
