20 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



part of its movement of displacement is distributed to the Union fault. The 

 prevailing dip of the formations is to the east, except in the vicinity of the 

 South Evans anticline. 



Weston fault. This fault is approximately parallel with Ball Mountain 

 fault, and follows the same general direction that it had in the area already 

 described outside the limits of the Leadville map. From its intersection 

 with Mosquito fault in Empire gulch, it crosses the Long and Derry Ridge, 

 near the foot of the steeper slope of the Upper Long and Deny Hill, and 

 descends into Iowa gulch just east of the Ella Beeler tunnel (E-7), where 

 it is joined by the Union fault; it runs thence diagonally up the southwest 

 slope of Green Mountain, a little east of the North Star (E-23) and Alta 

 (E-22), and crosses the head of California gulch between the Tiger shaft 

 (E-24) and the Ella tunnel (F-39). From here up the slope of Breece Hill 

 its position cannot be exactly defined, owing to the fact that Pyritiferous 

 Porphyry forms the reck surface on either side. In the ground of the 

 Highland Chief No. 2, however, it passes between two shafts of that claim 

 (F-40 and F-41), the former of which is in the Weber Grits and the 

 latter in Pyritiferous Porphyry, and just east of its main shaft (F 59) ; it 

 then follows the crest of the ridge to its north point and down its steep north 

 slope between the Chemung tunnel on the east and the Fenian Queen on the 

 west, along the line of the west fork of Lincoln gulch to Big Evans gulch, 

 which it crosses just above the month of Lincoln gulch. On the south 

 slope of Prospect Mountain its movement of displacement becomes \ery 

 slight, and is proved only by the discrepancy in the position of the divid- 

 ing line between Weber Shales and Gray Porphyry, as shown in the Still- 

 well (K-ll), La Harpe (K-12), and other shafts in Little Evans gulch 

 on the one side and in the Mary Able (K-35) on the other. 



The movement of displacement of this fault is quite remarkable, being 

 an upthrow to the west of about six hundred feet in Iowa gulch and about 

 the same amount of displacement reversed, the upthrow being on the east 

 side, near the mouth of Lincoln gulch, opposite the South Evans anticline. 

 This movement becomes null between these two points somewhere in the 

 neighborhood of the Yates shaft (F-6(i) on Breece Hill. 



