PROGRESS  REPORT  ON  PARK  CITY  MINING  DISTRICT,  UTAH. 
By  J.  M.  Boutwell. 
STATEMENT  OF  PROGRESS. 
At  the  date  of  writing  the  last  progress  report  on  the  survey  of 
this  district,0  January,  1904,  the  detailed  study  of  the  ore  bodies  was 
being  made.  When  this  underground  work  had  been  nearly  finished 
it  was  discontinued  temporarily  to  complete  other  work,  but  office 
study  was  continued  through  the  winter  and  spring  of  1903-4.  The 
most  important  result  then  accomplished  was  a  thorough  study,  mi- 
croscopically, of  the  igneous  rocks  of  the  district  by  Mr.  L.  H.  Wool 
sey.  The  field  work  was  again  taken  up  in  the  season  of  1904  and 
finished  in  December  of  that  year.  This  included  the  detailed  map- 
ping of  the  surface  geology  in  the  areas  shown  on  the  Park  City 
special  map  and  on  the  larger  scale  special  map,  the  detailed  exami- 
nation of  the  geology  of  all  accessible  underground  workings,  with 
special  study  of  the  ore  deposits  and  the  investigation  of  particular 
geologic  problems.  At  the  conclusion  of  this  work  reconnaissance 
work  on  problems  of  geologic  correlation  was  carried  on  in  the  Wa- 
satch range,  in  the  neighboring  mining  camps  in  the  Cottonwood 
region,  west  of  Park  City,  and  in  the  areas  north  and  south  of  this 
general  locality.  The  work  in  this  district  affords  the  basis  for  a 
detailed  statement  on  the  occurrence  and  origin  of  the  ore  deposits, 
proof  of  the  character  and  amount  of  faulting  and  intrusion  which 
directly  affect  the  occurrence  and  continuance  of  ore  bodies,  sugges- 
tions as  to  best  areas  for  prospecting,  and  evidence  on  the  perma- 
nence of  old  and  discovery  of  new  ore  bodies,  and  thus  on  the  future 
of  the  camp.  Significant  facts,  mainly  of  a  paleontologic  and  strati- 
graphic  nature,  have  also  been  found  which  throw  new  light  upon 
the  geologic  history  of  the  region.     After  careful  study  of  the  evi- 
a  Boutwell,  J.  M.,  Progress  report  on  the  Park  City  ruining  district,  Utah  :  Bull.  U.  S. 
Geol.  Survey  No.  225,  pp.  141-150. 
150 
