diller.1  SO-CALLED   IRON    ORE    NEAR    PORTLAND,    OREG.  347 
In  describing  a  trachyte,  Volume  TT,  page  585.  Mr.  Emmons  re- 
marks : 
Apparently  inclosed  in  this  trachyte,  on  the  south  hank  of  the  river  at  the 
mouth  of  a  little  side  canyon,  is  a  hill  a  few  hundred  feet  in  height  containing 
a  large  mass  of  iron  ore  remarkably  fine  grained  and  having  a  thoroughly  con 
choidal  fracture.     At  a  little  distance  it  might  he  mistaken  for  a  basaltic  rock. 
An  analysis  of  this  ore  made  by  Mr.  B.  E.  Brewster  gave  the  following  results: 
Ferric   oxide 84.  217 
Alumina     .ITS 
Manganous   oxide 1.  454 
Magnesia    .  472 
Water 1.713 
Insoluble  residue 12.518 
Total _   100.552 
which  would  give  a  percentage  of  metallic  iron  58.95.  The  occurrence  of  such 
a  body  of  iron  ore  in  the  midst  of  volcanic  rocks  is  an  interesting  phenomenon, 
though  it  is  probably  too  far  from  any  source  of  fuel  supply  to  he  of  practical 
value.  It  is,  however,  a  remarkably  pure  ore,  being  entirely  free  from  phos- 
phorus or  sulphur,  though  containing  a  rather  high  percentage  of  silica. 
The  locality  from  which  this  remarkable  specimen  was  obtained 
has  not  since  been  studied  by  any  member  of  the  Geological  Survey. 
