24(5 The American Geologist. October, 1893 
a considerable proportion <»i' the light honey- yellow or amber- 
colored variety, generally known by the miners as "resin- 
jack." I have not yet seen any colorless and perfectly trans- 
parent blende in the Wisconsin ores, or in those of any lo- 
cality in the Mississippi valley. 
The jack, like the carbonate ore or bone, is prepared for 
market in three principal grades or conditions: 
1. The massive, hand-sorted, culled jack, cleaned as far as 
possible from all rock, pyrite, bone, and lead. 
2. The medium-sized fragments or "sieved jack," picked 
out from the mixed and broken Stuff of the mine and cleaned 
by washing. 
X. The jigged ore and "smittems." 
4. To the above we may now add the dressed-jack from the 
roasting process. 
The first commands the best price and is most desired by 
the smelters, though often carrying a considerable amount of 
pyrite in thin scales, which cannot be removed by the culling- 
hammer. The second grade contains a still greater admixture 
of pyrite. If pyrite is abundant in the original mass it can- 
not be profitably removed by hand, and the mixed ore is laid 
aside as unmerchantable, though sometimes sales are made to 
smelters at a greatly reduced price. The same observations 
apply to the jigged jack. If comparatively free of pyrite, it 
commands a good price, but it is generally impossible to ob- 
tain any large amount not thus contaminated. In the culling 
and sorting, employment is given to many boys during the 
summer months, the clean lumps of jack, freshly cleansed 
from the dirt of the mine by free washing, being picked out 
by hand at so much per box or per hundredweight. 
The chief market for the Wisconsin blende is at the spelter 
works of Wenona, Peru, and La Salle, Illinois, the route of 
delivery or transportation being by the Illinois Central rail- 
road branch southwards from AVarren. 
Occurrence of Barite. 
Barite (heavj^spar) is an occasional associate of the de- 
posits of blende, and usually occupies a medial position in 
the veins, being formed upon the horizontal sheets of jack, 
and generally in heaviest layers upon the lower side of the 
opening. It is rarely crystalline, but forms in rounded, snow- 
