Mineral Deposits of Southwest Wisconsin. — Blake. 243 
Chemical compound. Mineral species. Local name. 
Lead sulphide. Galenite. Mineral. 
Zinc carbonate. Smithsonite. Bone. 
Zinc sulphide. Sphalerite or blende. Jack. 
Iron sulphide. Pyrite or iron pyrites. Sulphur. 
Of these, the zinc-ores largely preponderate, and the pro- 
duction is increasing- with the constantly growing demands of 
the spelter and the white zinc-oxide industries. 
The lead-ore is not now so much sought as formerly, and 
most of the old deposits are regarded as exhausted, although 
now and then new discoveries are made. The production 
may be regarded, however, as chiefly incidental to the exploit- 
ation of the zinc-deposits. As these are followed, new de- 
posits of lead-ore are sometimes uncovered, and in some of 
the zinc-deposits a little galena is intermingled with the 
carbonate and with the blende. 
The bulk of the shipments of lead-ore is in the form of coarse 
lump-galenite in large sheets ("sheet mineral"), or masses 
("chunk mineral' 1 ), or in crystalline masses as broken out from 
the deposits and culled by hand. When in large cubical crystals 
the ore is known as " block-ore " or " cog-wheel mineral," or 
"dice-mineral," if in smaller cubes. The name "mineral" 
for all forms of lead-ore is in general use. When the galen- 
ite is the product of separation by jigging from either dry- 
bone or jack, it is of course broken up into small pieces and 
finer, and it is then somewhat contaminated with residues of 
pyrite and of jack, or possibly barytes, by which its per cent- 
age is lowered. It is sold by the "thousand" (thousand 
pounds), and the price varies with the market value of pig- 
lead and the immediate needs of the smelters. In 1892 it 
ranged from $20 to $25 per thousand pounds, or from $40 to 
$50 per ton. It has special value to smelters by reason of its 
purity, being without arsenic, antimony, or silver, and thus 
furnishing a clean lead for corroding. 
The total shipments of zinc- and lead-ores from Benton, the 
principal ore-shipping railway station in the southwestern 
part of the lead- and zinc-region, amounted in 1892 to 13,- 
800,000 pounds, of which the le;id-ore was SHI). 000 pounds, or 
only about 6 percent, of the whole. This may he taken as repre- 
sentative of the present ratio of production by weight, though 
in the case of some new discovery of lead-ore the shipments 
for a season may be greatly increased. 
