Mineral Deposits of Southwest Wisconsin. — Blake. 237 
THE MINERAL DEPOSITS OF SOUTHWEST 
WISCONSIN. 
By William P. Blake, New Haven, Conn., and Shullsburg, Wis. 
The numerous and copious reports of geological surveys 
made in the lead and zinc region of Wisconsin leave, perhaps. 
but little room for any original work, or for descriptive de- 
tails of the nature and origin of the deposits not already 
given in the exhaustive memoirs of Percival, Whitney and 
Chamberlin and their associates. However, since the com- 
pletion of the last survey, in 1S79. much more attention has 
been given than before to the exploration of the ores of zinc. 
especially of late years, since the region has been better 
opened up by railways and the zinc industry of the country 
has assumed large proportions, giving a constantly increasing 
demand for zinc ores. 
A residence of more than a year in the region, and the ac- 
tive direction during that time of mining operations over a 
considerable area, have familiarized me with the forms and 
peculiarities of many of the deposits; and it appears prob- 
able that some observations upon them, especially from the 
mining and commercial standpoint, may interest the members 
of the Institute. A few notes on the structure of the deposits 
from the mineralogical and chemical standpoints have already 
been presented by Die to the Wisconsin Academy of Arts and 
Sciences.* 
The presence of lead-ore in the soil at many points along 
the Mississippi river was well known to the aborigines, and 
early attracted the attention of the frontier traders, who pur- 
chased from the Indians the ore and even lead smelted out 
by the squaws. The demand for the lead-ore soon increased, 
and it became one of the early and potent factors determining 
the settlement of southwestern Wisconsin, and the develop- 
ment of its mining and agricultural resources. The mines of 
that section, together with those of Missouri and the Missis- 
sippi valley, may be said to have been the cradle of mining 
in the western United States. The deposits of ore being at 
or near the surface, and being numerous and widely distrib- 
uted, afforded to poor men an opportunity to mine on their 
* December Meeting at Madison, 1892, " Notes on the Structure of 
the Ore Deposits of Southwest Wisconsin." 
