Wisconsin and Missouri Lead Region. 37 
Beneath the cliff limestone is a thin stratum of blue limestone, 
and this rests on a body of brown sandstone. As one goes from 
the southern townships of Wisconsin towards the north, this blue 
limestone is observed to become higher and higher: in the hills, 
and the lead diggings to be every where above it. Though the 
sandstone rocks come out in bold bluffs on the'sides of the hills, 
no veins of ore are ever found in them; but in the cliff lime- 
stone above, they are found, though the rocks and its fissures lie 
hid under a great depth of soils The section annexed.(Fig. 1) 
represents this order of superposition, the character of the fissures, 
and about the relative proportion that the three rocks bear in the 
hills near Mineral Point. 
SSN — 
ST eS Wf 
These fissures are of every aupese of width, from fity fe feet 
down to thin cracks; all of them do not contain ore ; the large 
chambers, when they have any mineral in them, are iftied on the 
walls with a coating of lead ore, seldom over a foot thick, while 
the interior is filled with clay. Sometimes across the crevices 
run horizontal layers of galena; and again it occurs in loose 
“chunks” in the clay of the fissures or’ ‘of the soil above, and 
again it runs in a vertical sheet down, or still again filling narrow 
2 appearance of a vein dna of a bed in the solid rock. 
ut the pitcher the only ore these fissures contain ; mixed 
with it in every proportion, and even sometim mes getting the bet- 
ter of the galena and shutting it out odie soceur both the 
carbonate and sulphuret of zine; the one known to the miners 
by the name of “dry bone,” the other “black Jack.” “From the 
abundance of the carbonate of zinc, and its being an ore that 
when clear yields about 60 per cent. of the oxide, it seems prob- 
able that it will sometime become an object of importance; now 
it is considered a great obstruction whenever met with, and the 
galena when mixed with much of the zinc ore, brities an infe- 
rior price. 
~The direction of the fissures downwards is as variable as their 
size and shape. They run like cracks through a rock—some- 
* times vertically, sometimes inclined, and sometimes horizontally 
