MINES OF BEACON HILL. 
351 
intrusive contact, along which there has been occasionally a little local movement. 
Sills and dikes of phonolite are particularly abundant in the granite near the main 
phonolite mass, as may be well seen on level 2 and in the east branch of the new 
drainage tunnel. The contact dips steeply into Beacon Hill, usually at 75° or 80°. 
(See fig. 40.) 
LODE SYSTEMS. 
The principal lodes of the El Paso are the El Paso, Tillery, and C. K. & N. The 
El Paso and Tillery strike in general N. 35° E. Both dip northwest, the El Paso 
at about 70° and the Tillery at about 65°. They thus converge downward. At the 
X 
c 
o 
© o 
<0 
Fig. 40 — Diagrammatic northwest-southeast section across Beacon TTill, through El Paso and Zoe shafts. 
surface, near the old shaft, they are approximately 150 feet apart, while in the 
southwest part of level 4 they are apparently together. They diverge, however, to 
the northeast, and at the new shaft are 70 feet apart on level 4. Both lodes are 
rather irregular in strike and dip. The Tillery is very indistinct north of the main 
shaft and has not proved important in that direction. An east crosscut on level 2 
shows that the granite through which the Tillery lode would pass if it persisted so 
far north is too much shattered to allow the identification of the lode. The maxi¬ 
mum explored length of the Tillery lode is about 700 feet, chiefly in the vicinity of 
the old shaft. The El Paso lode has been explored from a point about 450 feet south¬ 
west of the old shaft to a point 800 feet northeast of the new shaft, a total length 
of 1,850 feet. On level 1 the El Paso lode meets the El Paso dike just east of the 
new shaft. The lode follows the foot wall of the dike for about 175 feet, and then 
turns slightly northward across the dike and continues on to the C. K. & X. lode. 
On level 2 the lode and dike exhibit a similar relation, the crossing on this level being 
about 500 feet northeast of the shaft (fig. 43). On levels 3 and 4 the intersection 
occurs successively farther north and nearer the C. K. & X. lode, but the develop¬ 
ment in this part of the mine was not extensive enough at the time of visit to make 
clear all the details of the relation between the dike and the El Paso and C. K. & X. 
lodes. Xear the dike the El Paso lode is rather irregular and changeable in dip 
and may be accompanied by considerable subsidiary Assuring. At the point 
