CONTRIBUTIONS  TO  ECONOMIC  GEOLOGY,  1904. 
S.  F.  Emmons, 
C.  W.  Hayes, 
Geologists  in  Charge. 
INTRODUCTION. 
By  C.  W.  Hayes,  Geologist  in  Charge  of  Geology. 
This  bulletin  is  the  third  of  a  series,  the  first  being  Bulletin  No.  218 
id  the  second  Bulletin  No.  225,  Contributions  to  Economic  Geology 
)r  1902  and  for  1903,  respectively.  These  bulletins  are  prepared 
rimarily  with  a  view  to  securing  prompt  publication  of  the  eco- 
omic  results  of  investigations  made  by  the  United  States  Geological 
urvey.  They  arc  designed  to  meet  the  wants  of  the  busy  man,  and 
:e  so  condensed  that  he  will  be  able  to  obtain  results  and  conclusions 
ith  a  minimum  expenditure  of  time  and  energy.  They  also  afford 
better  idea  of  the  work  which  the  Survey  as  an  organization  is  car- 
ping on  for  the  direct  advancement  of  mining  interests  throughout 
le  country  than  can  readily  be  obtained  from  the  more  voluminous 
sports.  The  bulletins  for  1902  and  1908  have  been  so  favorably 
;ceived  by  those  interested  in  the  development  of  the  mineral  indus- 
ies  of  the  United  States  that  it  is  proposed  to  issue  early  in  each 
ilendar  year  a  similar  publication  containing  the  results  of  the  last 
3ar's  field  work  in  economic  geology. 
In  the  two  preceding  bulletins  of  this  series  were  included  numer- 
is  papers  relating  to  the  economic  geology  of  Alaska.  In  view  of 
le  rapid  increase  during  the  past  year  of  economic  work  both  in 
laska  and  in  the  States  and  the  organization  of  a  division  of  Alas- 
m  mineral  resources,  distinct  from  the  division  of  geology,  it  has 
ben  considered  advisable  to  exclude  from  the  present  volume  all 
japers  relating  to  Alaska.  These  have  been  brought  together  into  a 
$arate  volume  entitled  "  Report  of  Progress  of  Investigations  of 
iaeral  Resources  of  Alaska  in  1904,"  Bulletin  No.  259.  It  is 
Sieved  that  the  information  will  be  most  economically  and  effect- 
rely  disseminated  bv  this  segregation. 
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