Bulletin  No.  225  Series  A,  Economic  Geology, 
DEPARTMENT  OF  THE  INTERIOR 
UNITED  STATES  GEOLOGICAL  SURVEY 
CHARLES  D.  WALCOTT,  Director 
CONTRIBUTIONS 
TO 
ECONOMIC   GEOLOGY 
1903 
S.  F.   EMMONS 
O.  W.  HAYES 
G-eologists  in  Charge 
WASHINGTON 
GOVERNMENT     PRINTING     OFFICE 
1904 
