346  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
I 
In  view  of  the  great  differences  in  the  amount  of  iron  found  in  the 
so-called  "  iron  ore  "  by  the  various  chemists,  it  should  be  said  that 
they  did  not  analyze  exactly  the  same  specimens.  The  specimens  for 
analysis  by  the  Survey  were  collected  by  myself,  in  Mr.  Roberts's 
presence,  so  as  to  be  sure  and  get  the  right  material.  We  have  also 
some  specimens  kindly  sent  in  later  by  Mr.  Roberts.  One  of  the 
specimens,  he  says,  "  contains  about  the  average  amount  of  iron." 
It  was  given  to  Mr.  Steiger  for  examination,  and  he  reports  15.26 
per  cent  of  Fe203,  equivalent  to  10.68  per  cent  of  metallic  iron. 
When  determining  the  amount  of  iron  present,  Mr.  Steiger,  in 
the  Geological  Survey  laboratory,  followed  a  well-established  method 
of  procedure,  using  the  standard  potassium-permanganate  solution 
for  titration. 
No  analysis  was  made  of  the  basalt  which  Mr.  Roberts  said  he 
used  as  a  flux,  but  a  thin  section  of  it  shows  it  to  be  a  normal  feld- 
spar basalt,  which  is  rather  rich  in  olivine  and  most  likely  contains 
about  9  per  cent  of  iron.  If,  therefore,  the  basalt  can  be  used  to 
flux  the  basalt  tuff,  it  would  add  its  iron  to  that  of  the  tuff,  but 
would  leave  the  general  average  of  the  charge,  ore  and  flux  com- 
bined, not  over  10  per  cent  of  metallic  iron,  an  amount  which  is 
below  the  lowest  that  is  in  general  worked  successfully  as  a  source 
of  iron,  even  with  the  most  advantageous  circumstances  in  the 
accessibility  of  ore,  flux,  and  fuel,  as  well  as  distribution  of  output. 
In  order  to  get  the  opinion  of  an  expert  who  is  well  qualified  to 
judge  of  such  matters,  a  letter  stating  the  essential  facts  was  referred 
by  the  office  to  Mr.  John  Birkinbine,  of  Philadelphia,  whose  reply  is 
as  follows: 
Acknowledging  receipt  of  the  letter  of  J.  S.  Diller  concerning  the  so-called 
"  iron  ore  "  obtained  along  the  Columbia  River,  I  would  state  that  it  seems  to 
be  a  ferruginous  basalt  tuff  rather  than  an  iron  ore,  and  I  doubt  very  much  if 
it  would  be  practicable  for  the  commercial  manufacture  of  iron  by  the  ordinary 
smelting  process.  Its  contents  of  magnesia  and  lime  would  assist  in  fluxing 
the  necessary  amount  of  silica,  but  it  would  undoubtedly  have  to  have  addi- 
tional flux,  and  the  percentage  of  metallic  iron  would  demand  that  fully  10 
tons  of  the  material  would  be  required  to  produce  a  ton  of  pig  iron.  I  also 
notice  that  the  titanic  acid  in  the  analyses  is  3.37  per  cent.  This  would  assist 
in  making  the  material  refractory  and  demand  excessive  fuel. 
The  furnace  fed  with  material  of  this  character  would  be  rather  a  slag  pro- 
ducer than  an  iron  producer,  and  I  question  very  seriously  whether  any  eco- 
nomical value  would  result  from  treating  the  ore  in  the  ordinary  smelting  fur- 
nace. It  is  also  questionable,  even  with  electricity  supplied  at  a  very  low  rate, 
if  the  metallic  contents  of  this  ore  could  he  separated  and  made  marketable. 
In  the  above  reply  I  am  treating  the  ore  as  not  exceeding  the  analyses  given 
by  Mr.  Diller. 
The  consideration  of  this  ferriferous  basaltic  material  on  the 
Columbia  recalls  a  discovery  by  Mr.  S.  F.  Emmons  while  engaged  on 
the  Fortieth  Parallel  Survey,  near  Palisade  Canyon. 
