470 WISCONSIN STATE AGRICULTURAL SOCIETY. 
cant these few feet of sandstone appear when compared with 
the hard crystalline bed of toadstone that cuts off the 
veins of the first bed of the Derbyshire limestone. And 
when the intelligence and enterprise of Wisconsin waver 
before such an obstacle, can we blame that of Derbyshire for 
confining her mining operations to the upper bed of limestone 
for centuries? If we are to look to the history of other lead 
districts, similar to our own for information, it is certainly in 
favor of the extension of our ore-deposits into the lower strata. 
Before leaving the origin of our mineral veins, and the evi¬ 
dences of the action of forces from below, I would refer to one 
other class of phenomena noticed in connection with this north 
and south axis, both in the lead district and immediately to the 
north of it. 
Everv miner in the lead district is familiar with what are 
1/ 
called bars of rock, sometimes called sulphur bars. These 
bars of rock form no distinct part in the series, but are the 
same rock locally changed. Where they are found in the ga¬ 
lena limestone, (and we usually find them there,) the rock is 
changed from a comparatively soft, granular rock to a very 
hard, bluish gray, crystalline rock, as hard as any trap rock can 
be. I have known as high as one hundred dollars per foot 
paid for sinking a shaft in it. These bars are always found in 
connection with our best ore deposits, the ore olten extending 
away from them into softer rock; or as the ore approached 
from the other way, it is said to give out in a bar, or is cut off 
by a bar. In some places this hard, crystalline rock appears 
to have been broken up subsequent to this hardening process 
and the angular fragments cemented together by the oxide of 
iron in a crystalline condition, forming, what the geologist 
would call, a breccia, or a conglomerate with angular fragments 
of rock. 
These bars are not peculiar to any one locality in the lead 
district, but are found in almost every mining locality, and al¬ 
ways near the center, or where the richest deposits are found. 
At New Diggings, beautiful specimens of this “bar” rock may 
be found with these angular fragments cemented together with 
