228 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Printer Boy Hill and bending to the north beyond the Pilot tunnel, from 

 which it receives its name. It crosses California gulch a little above the 

 Lower Printer Boy mine, and White's Hill just east of the shaft L-34. 

 Beyond that point its position can no longer be defined, but it seems prob 

 able that it passes through a slight anticlinal fold under the Breece Hill 

 body of Pyritiferous Porphyry, the continuation of a fold farther north 

 which is proved by the explorations of the shafts in the neighborhood of the 

 Great Hope mine, above Evansville. 



union fault. The Union fault, which is principally developed south of 

 the limits of the map, lias a direction nearly parallel with the Mosquito 

 fault. As described in the preceding chapter, it crosses the western slope of 

 Empire Hill and disappears to the southward in the granite area adjoining 

 lower Weston gulch. Its displacement is an upthrow to the east, which 

 from a null point at its south end increases towards the north, reaching a 

 maximum of about one thousand feet at its junction with the Weston fault, 

 in Iowa gulch below the Ella Beeler tunnel, where the Archean comes in 

 contact with the upper portion of the White Porphyry above the Blue Lime- 

 stone. 



In the bed of Empire gulch Archean is exposed east of this fault, and 

 the overlying Cambrian and Silurian beds can be traced, sweeping up the 

 slopes on either side of the gulch, where not covered by the Empire 

 moraines. A few shafts and tunnels have penetrated the moraine material 

 to the underlying quartzite and silicious limestone. Such is the Little 

 Annie tunnel, just east of the fault, on the south slope of Long and Deny 

 Hill, which ran through moraine material into White Porphyry, and at 

 whose end a winze was sunk into the underlying limestone. Farther east 

 the Coffee, Louis Tell, California Rose, and Caledonian tunnels are run 

 upon the contact of White Porphyry and Silurian limestone, which beyond 

 them abut against the granite on the other side of Weston fault. 



Long and Derry Ridge. The structure of this ridge is best explained by 

 Section I, Atlas Sheet XX. The actual line of the Union fault on the crest 

 of the ridge is undefinable, since White Porphyry is found on either side. 

 Two small outcrops are found near the crest of the hill, adjoining the Weston 

 fault, which represent portions of the Blue Limestone above the lower beds 



