166 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bum.. 213.1 
Wolverine claims. — This property, owned by the Cold Water Min- 
ing Company, is located about 2^ miles south of Pearl. The eountrJ 
rock is extremely variable, showing all gradations from black dioritet 
to pink granite, and the granites are in part hornblende-granites 
related to the diorites. The ore in the discovery shaft is chalcocitel 
containing disseminated specks of chalcopyrite and zinc blende. I 
This ore is of a very friable nature, and on exposure crumbles to a 1 
sand. An examination of the material thrown out and of the neigh-' 
boring outcrops shows that the ore has resulted from the replacement! 
of biotite in a rock originally composed of quartz, biotite, and garnets 
Of these three minerals the quartz alone remains in the form of a 
granular gangne surrounded by the sulphides of copper. The extent 
of this ore and the shape of the ore body have not been ascertained,, 
but surface outcrops are sufficient to show that the mass of the rock in 
which it occurs is rather limited, having the shape of a wedge which! 
disappears toward the southeast. 
The shaft where the work is now being done is situated a few feet< 
north of the point of the wedge of granite, and through its top there' 
passes a vein having a course N. 40° W. This shaft is in pink gran-' 
ite, but diorite is present on both sides. The general trend of thei 
banded structure is N. 80° E. The various rocks near the mouth of) 
the shaft are cut in an intricate manner by small dikes of pegmatite, 
and certain coarse phases of granite in the vicinity contain red oxide 1 
of iron, which has been derived probably from magnetite. Some good; 
specimens of chalcopyrite have been taken from the shaft, but no 
regular deposit of the mineral has been proved thus far. 
Mount Zirlcd shaft. — The shaft on the property of the Mount ZirJ 
kel Company is located about 2,500 feet northeast of the Wolverine] 
shaft, and while the general nature of the country rock is identical,! 
the ore here occurs in a different manner, nainelj 7 , in granite pegma- 
tite and in a broken or brecciated gneiss adjacent. 
The shaft has been sunk to a depth of 185 feet, and drifts started 
at 71 and 155 feet. The pegmatite is extremely coarse grained, and 
is composed of quartz and cream-colored feldspar, with occasional 
flakes of mica. This material has been fractured and chalcopyrite 
has been deposited in the openings thus formed, sometimes as a filling 
of brecciated bands, and at other times occurring along cracks which 
pass from the feldspar into the quartz. As shown in the workings,! 
the pegmatite has a course approximately N. 80° E. For the first 35 
feet there is a dip of 70° S., then for 90 feet the vein stands nearly 
vertical, and below 125 feet it dips perhaps 75° N. The pegmatite is 
inclosed in a much broken gneiss of variable composition. On the) 
north side of the vein diorite and granite seem to be intricately mixed, 
and here local pockets of chalcopyrite are found in the 155-foot level, 
and also in the discovery shaft at the surface, where there is a well- 
defined streak of iron oxide stained with green copper mineral, evi-\ 
