bain.]  LEAD    AND    ZINC    RESOURCES    OF    UNITED    STATES.  255 
DESILVERIZED    LEAD. 
Idaho. — The  most  important  single  lead-producing  State  is  Idaho, 
and  in  this  State  more  than  96  per  cent  of  the  output  is  from  the 
Coeur  d'Alene  district.  The  geology  and  ore  deposits  of  this  dis- 
trict are  separately  discussed  in  this  bulletin  by  Mr.  Ransome.  The 
most  important  Idaho  district  aside  from  the  Coeur  d'Alene  is  that 
of  Wood  River.  This  district,  located  near  Hailey,  is  estimated  to 
have  produced  about  3,000  tons  of  lead  in  1903.  The  ores  occur  in 
closely  folded  limestones,  quartzites,  and  shales  of  Carboniferous  age 
in  connection  with  certain  intrusive  masses  of  granite.  They  are 
argentiferous,  and  have  been  discussed  in  some  detail  by  Mr.  Lind- 
gren." 
Utah. — The  second  producer  among  the  Western  States  is  Utah. 
The  only  available  distribution  of  the  production,  estimated  by  the 
Director  of  the  Mint  in  round  numbers  at  55,500  short  tons  in  1902, 
is  as  below : 
Production  of  lead,  by  leading  comities,  from   Utah  ores,  1902J> 
Short  tons. 
Summit 38,(524 
Juab    10,  183 
Beaver    2, 511 
Tooele 1,075 
Salt  Lake ■ 1,  G27 
The  production  of  Summit  County  comes  from  the  Park  City 
district,  and  that  of  Salt  Lake  County  from  the  Bingham  Canyon 
and  Cottonwood  districts.  These  are  elsewhere  discussed  by  Mr. 
Boutwell.  The  Juab  County  production  is  principally  from  the 
Tintic  region,  which  has  been  described  by  Messrs.  Tower  and 
Smith.' 
The  Beaver  County  production  is  from  the  Frisco  district,  in 
which  the  famous  Horn  Silver  mine  is  the  most  important  producer. 
This  property  has  been  briefly  described  by  Mr.  Emmons/  The  ore 
body  occurs  along  a  faulting  fissure  at  the  contact  of  an  altered 
igneous  rock  and  a  dolomite  of  uncertain  age,  and  near  an  intrusive 
■mass  of  monzonite.  The  limestone,  where  in  contact  with  the  mon- 
zonite,  has  been  subjected  to  contact  metamorphism.  The  mine  is 
essentially  a  lead  mine,  though  zinc  and  copper  occur  in  quantity  and 
'silver  has  always  contributed  largely  to  the  value  of  the  ore. 
"  Lind^ren,  Waldemiar,  Twentieth  Ann.  Kept.  U.  S.  Seol.  Survey,  pt.  3,  11)00,  pp. 
JUL90-218. 
S      ''  Tntem,  15.   II..   Report   of  the  Director  of  the  Mint.   1903,  pp.  200-206. 
i     e  Tower,  G.   W.,  and  Smith,  G.  <>..  Geology  and  mining  industry  of  the  Tintic  district. 
ilTtah  :    Nineteenth  Ann.  Kept.   I'.  S.  Geol.  Survey,  pt.  3,   L899,  pp.  001-707. 
d  Emmons;  S.  F..  The  Delamar  and  Horn  Silver  mines:  Trans.  Am.  Inst.  Min.  Eng., 
vol.  31,  1901,  pp.  675-683. 
