ZINC  AND  LEAD  DEPOSITS  OF  SOUTHWESTERN  WISCONSIN. 
By  U.  S.  Grant. 
INTRODUCTION. 
The  lead  and  zinc  region  of  Wisconsin  comprises  Grant,  Lafayette,] 
and  Iowa  counties.  It  lies  between  the  Wisconsin  Kiver  on  the  north, 
the  Illinois  boundary  on  the  south,  and  the  Mississippi  River  on  the 
west.  Mining  for  lead  began  here  about  eighty  years  ago  and  hasj 
continued  to  the  present  time,  Zinc  mining  was  not  undertaken  until] 
some  years  after  lead  mining  began,  but  at  the  present  time  the  zinc 
ores  are  the  most  important.  There  was  a  marked  depression  in  the 
mining  business  in  this  region  until  within  the  last  four  or  five  years, 
when  active  operations  were  resumed,  and  the  region  has  again  be-J 
come  an  active  producer  of  lead,  and  especially  of  zinc. 
The  Wisconsin  region  comprises  the  most  important  part  of  thj 
upper  Mississippi  Valley  lead  and  zinc  district,  which  also  includes 
adjoining  portions  of  Iowa  and  Illinois.  Investigations  in  this  disj 
trict  have  been  recently  carried  on  by  the  United  States  Geological 
Survey  and  by  the  Wisconsin  Geological  and  Natural  History  Survey! 
and  some  preliminary  results  have  been  published."  The  Federal! 
Survey  has  in  preparation  an  extensive  report  on  the  ore  deposits  oi 
the  upper  Mississippi  Valley  lead  and  zinc  district  and  a  report  on  the 
geology  of  the  Mineral  Point  quadrangle,  which  includes  the  major j 
part  of  the  producing  mines  in  Wisconsin.  The  State  survey  has  ill 
preparation  a  report  which  will  include  detailed  topographic  and  geo-l 
logic  maps  of  several  areas  in  which  mining  operations  are  now  active.] 
The  principal  towns  of  the  Wisconsin  region  are  Mineral  Point, 
Platteville,  Dodgeville,  Darlington,  and  Shullsburg.  Branch  line! 
of  the  Chicago  and  Northwestern,  the  Chicago,  Milwaukee  and  StJ 
9  Paul,  and  the  Illinois  Central  railways  reach  this  region  and  furnish! 
an  outlet  for  ore  to  the  zinc  smelters  at  Lasalle,  Peru,  and  WenonaJ 
111.,  at  which  points  much  of  the  zinc  ore  is  reduced.     Some  is  alsJ 
"Bain,  H.  F.,  Load  and  zinc  deposits  of  Illinois:  Bull.  U.  S.  Geol.  Survey  No.  229 
1904,  pp.  202-207. 
Bain,  II.  F.,  Zinc  and  lead  deposits  of  northwestern  Illinois:  Bull.  U.  S.  Geol.  Surveyj 
No.  246,  1905. 
Grant,   U.   S.,  Preliminary  report  on   the  lead  and  zinc  deposits  of  southwestern   Wis- 
consin :    Bull.  Wisconsin  Geol.  Nat.  Hist.  Survey  No.  9,  1903. 
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