406 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
9 
TRACHYTE MINE. 
The Trachyte mine, on the claim of the same name, lies 500 feet southeast of 
the Deadwood, is also the property of the New Zealand Mining Company. It is 
explored by a shaft 400 feet deep and four levels, representing a total development 
of 2,500 to 3,000 feet. The elevation of the collar is 10,462 feet. The country rock 
is latite-phonolite, oxidized in places. The basalt dike from Deadwood No. 2 passes 
not far west of the shaft. ' 
Owing to accumulation of ice in the shaft below level 1, only that level was 
entered. A crosscut 120 feet to the north discloses a vein with a trend slightly 
south of east, and dipping about 65° N. It has been stoped from close to the sur¬ 
face down to at least level 2, for a distance of 200 to 300 feet along the vein. The 
character of the vein matter could not be seen. 
PEARL MINE. , 
The Pearl mine is situated between the Trachyte and the Deadwood No. 2, and 
has some workings on the Deadwood No. 2 basalt dike. 
DEADWOOD NO. 2 MINE 
INTRODUCTION. 
Near the south end of the Deadwood claim a shaft has been sunk and work done 
principally by lessees. It is called the Deadwood No. 2 mine, and is estimated to 
have produced $150,000. The shaft is 850 feet deep and has nine levels which rep¬ 
resent about 4,000 feet of drifting and crosscutting. The elevation of the collar is 
10,410 feet. 
GEOLOGICAL FEATURES. 
The shaft and workings are in latite-phonolite. Levels 2 and 9 appear to enter 
breccia 140 feet west of the shaft, but this point could not be definitely determined. 
A 3-foot vertical phonolite dike striking about north and south is exposed on level 
2 about 150 feet west of the shaft. The important geological feature of the mine is 
a basaltic dike cut by the shaft at level 1, having a general course about N. 20° W. 
and dipping on an average 80° W. The dip varies considerably, however, as does 
also the strike. The dike is irregular in width, ranging from 1 to 5 feet, but becomes 
more uniform with depth. On level 1 it appears to branch south of the shaft. The 
drift leaves the dike and soon cuts another approximately parallel dike. On level 2 
a similar occurrence is met with just north of the shaft. Twenty feet north of the 
shaft on level 1 the dike is faulted, the north part being thrown 1 foot to the west. 
A narrow seam with a strike parallel to the dike, but which dips every steeply toward 
the west, branches off from the dike just below level 1. On level 6 this seam, which 
is still at the shaft, carries 6 inches of decomposed basalt. It is cut again on the 
lower levels, where the dip becomes slightly less and the width of basalt increases 
to 15 inches on level 9. The main basalt dike shows a corresponding loss in width 
as the other widens. 
