CONTRIBUTIONS  TO  ECONOMIC  GEOLOGY,  1903. 
S.  F.  Emmons, 
C.  W.  Hayes, 
Geologists  in   Charge. 
INTRODUCTION. 
By  C.  W.  Hayes,  Geologist  in  Charge  of  Geology. 
This  bulletin  is  the  second  of  a  series,  the  first  being  Bulletin  No. 
213,  Contributions  to  Economic  Geology  for  1902.  These  bulletins 
are  prepared  primarily  with  a  view  to  securing  prompt  publication  of 
the  economic  results  of  investigations  by  the  United  States  Geological 
Survey.  They  are  designed  to  meet  the  wants  of  the  busy  man,  and 
are  so  condensed  that  he  will  be  able  to  obtain  results  and  conclusions 
with  a  minimum  expenditure  of  time  and  energy.  They  also  afford  a 
better  idea  of  the  work  which  the  Survey  as  an  organization  is  carry- 
ing on  for  the  direct  advancement  of  mining  interests  throughout  the 
country  than  can  readily  be  obtained  from  the  more  voluminous 
reports.  The  bulletin  for  1902  was  so  favorably  received  by  those 
interested  in  the  development  of  the  mineral  industries  of  the  United 
States  that  it  is  proposed  to  publish  earl}r  in  each  calendar  }^ear  a 
similar  bulletin  containing  the  results  of  the  last  year's  field  work  in 
economic  geology. 
In  the  preparation  of  the  present  volume  promptness  of  publication 
has  been  made  secondary  only  to  the  economic  utility  of  the  material 
presented.  The  papers  included  are  such  only  as  have  a  direct 
economic  bearing,  all  questions  of  purely  scientific  interest  being 
excluded. 
The  papers  are  of  two  classes:  (1)  Preliminary  discussions  of  the 
results  of  extended  economic  investigations,  which  will  later  be  pub- 
lished by  the  Survey  in  more  detailed  form;  (2)  comparatively  detailed 
descriptions  of  occurrences  of  economic  interest,  noted  by  geologists 
of  the  Survey  in  the  course  of  their  field  work,  but  not  of  sufficient 
importance  to  necessitate  a  later  and  more  extended  description.  A 
third  class  of  papers  was  included  in  the  bulletin  for  1902,  namely, 
11 
