L  /tf.3' 
Bulletin  No.  260 
Series  A,  Economic  Geology,  53 
DEPARTMENT  OF  THE  INTERIOR 
UNITED  STATES  GEOLOGICAL  SURVEY 
CHARLES  D.  WALCOTT,  Director 
CONTRIBUTIONS 
ECONOMIC   GEOLOGY 
1  9  O  4 
S.   F.   EMMONS 
C.    W.    HAYES 
G-eoiogists  in  Charge 
WASHINGTON 
GOVERNMENT     PRINTING     OFFICE 
1905 
