diller.] COPPEE DEPOSITS OF REDDING REGION, CAL. 
127 
associated with the largest ore bodies yet discovered is basaltic in 
character and particularly rich in soda, as indicated by the following 
chemical analysis (2) by Dr. Allen. 
Analyses of country rock of Bully Hill district. 
SiCV 
ALA 
FeA 
FeO. 
MgO 
CaO. 
Na 2 
K 2 0. 
H 2 0- 
H 2 OH 
Ti0 2 . 
Zr0 2 
C0 2 . 
PA- 
s____ 
Cr 2 3 
MnO 
BaO. 
81.25 
49.85 
9.03 
17.00 
.63 
4.02 
.40 
5.51 
2.48 
7.G5 
Trace? 
1.18 
.25 
4.78 
1.82 
None. 
1.09 
2.16 
2.81 
6.65 
.08 
.97 
None. 
None. 
None. 
None. 
Trace. 
.10 
.35 
.07 
None. 
None. 
Trace. 
None. 
.05 
Trace. 
100. 24 
99.94 
.13 
.03 
100.11 
99.91 
1. Bully Hill mine 400 feet west of ore body, west end of tunnel 2. 
2. Bully Hill mine east of ore body, in tunnel 3. 
g through 
This interesting rock (2) occurs in the form of a dike cuttii 
the older igneous rocks and the Triassic slates. Much of the rock in 
he mine, especially in the Copper City workings, looks like slate and is 
so called by the miners. The resemblance, however, is only superficial 
md results from the squeezing and shearing of the metarhyolite until 
t possesses a slaty structure. The ore deposits are found in the zones 
)f shearing. 
The shear zones are usually of limited extent ; none have been traced 
ipon the surface for over a mile. They vary in width from a few 
nches to nearly a score of feet, and are either vertical or dip steeply 
o the west, trending a few degrees east of north. In Bully Hill there 
ppear to be three shear zones, two of which are well mineralized and 
ontain valuable ore bodies. They are nearly parallel and only a few 
