15N The American Geologist, March, 189* 
No. V shows an almost typical dolomite No. VI only a mag- 
nesian limestone. No. V is dark bluish gray in color, while 
No. VI is white and sparkling. No. VI is at the bottom, 
nearly, of the drill hole and is in contact with granite and has 
spots, and, in places, crystals of chondrocyte. Analysis No. 
V proves very conclusively the extension of the bed of crys- 
talline dolomite from its outcrop on the front vein to a 
distance (east) of about 900 feet on the surface, or, following 
down the dip, a distance of about 1,700 feet. 
On the surface, about fifteen feet back of the front vein 
(fig. 1, a-b), the limestone is bluish-gray and does not effer- 
vesce with acid; it is probably a true dolomite. This would 
indicate that the doloniitic hanging wall of the ore body is 
the same as that proved by the analysis ( No. IV) of the drill 
core from the hanging wall and four hundred feet from the 
surface. (See fig. 2, y-b, for position of drill hole.) As a 
proof of the surface extension of this dolomite an analysis 
was made of samples taken from a large pump station cut in 
the shaft which is being sunk (see fig. 1). This pump 
station is 450 feet from the surface. 
VII. 
Insoluble 0.09 
Fe 2 O., + Al, 3 0.85 
Ca C0 3 55.28 
MgCO^ 44.51 
Total 100.73 
This sample is 500 feet above the ore body at this point. 
Since the above analysis was made, however, the shaft has 
been sunk to 750 feet. The material passed through was 
principally limestone, probably dolomite, as it did not effer- 
vesce with acid, till at about a depth of 700 feet a sparkling, 
white limestone was reached, which showed a brisk efferves- 
cence. This limestone was two feet thick and lay upon a 
granite dike twelve feet thick. Below the dike for thirty-six 
feet, the present depth, the limestone is very coarsely crystal- 
line, the crystals of calcite being often six inches across. 
Above and below the dike the effervescing limestone, probably 
non-magnesian, is thickly studded with clusters and bands of 
bright crystalline masses of chondrodite, phlogopite (decom- 
posed by sulphuric acid), and tremolite. Above 450 feet, to 
