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OUR  MINERAL  RESERVES.

The  phosphate  reserves  in  the  East  are  not  large,  and  domestic  use
can  be  found  for  all  this  material.
The  States  of  Florida,  Tennessee,  and  South  Carolina  have  for
many  years  been  the  main  source  of  phosphate  rock  in  the  United
States.  The  output  of  Florida,  the  leading  State  in  phosphate-rock
production,  has  about  reached  its  maximum,  particularly  so  far  as
the  hard-rock  industry  is  concerned.  The  land-pebble  industry
continues  to  show  a  vigorous  growth.
In  Tennessee  the  brown-rock  deposits,  which  several  years  ago
were  given  but  a  brief  future  existence,  promise  to  yield  as  much  or
more  phosphate  than  has  already  been  extracted  from  them,  as  they
are  now  worked  on  a  large  scale  with  modern  machinery  and  under
modern  mining  methods.  Pioneer  methods  are,  however,  still  employed ­
  in  some  parts  of  the  brown-rock  phosphate  regions  and  are
attended  by  a  great  waste  of  good  material.  With  the  passing  of
the  brown  and  blue  phosphate  fields  into  the  control  of  the  larger
fertilizer  corporations,  which  practice  modern  mining  methods  and
have  installed  expensive  plants  to  treat  the  mined  rock,  a  gradual
change  has  taken  place,  and  the  life  of  the  fields  is  being  thereby
prolonged.
.  The  South  Carolina  field  was  the  first  to  be  exploited  on  a  commercial ­
  basis.  Though  mining  has  fallen  off  in  this  field  it  is  quite
likely  that  much  rock  remains  for  future  use.  As  the  most  readily
accessible  material  has  been  removed,  the  remaining  rock  will  be
correspondingly  expensive  to  mine.  The  product,  moreover,  being
of  medium  grade,  can  not  compete  with  higher-grade  rock  in  the
manufacture  of  superphosphate.  Hardly  any  rock  is  being  exported
from  this  field  at  the  present  time.
The  new  western  phosphate  field  was  discovered  in  1906,  and
although  for  economic  reasons  it  has  not  yet  produced  on  a  large
scale,  the  main  production  of  phosphates  in  the  future  will  probably
come  from  the  West,  where  the  principal  deposits  are  located  on
the  public  domain.  Some  of  the  economic  reasons  that  retard  the
development  of  the  western  phosphate  fields  are  comparative  newness, ­
  lack  of  transportation  facilities,  high  freight  rates,  and  remoteness ­
  from  centers  of  consumption.
Since  the  discovery  of  the  western  fields  systematic  investigation
has  been  prosecuted  by  the  Survey,  and  this  work  has  resulted  in
the  discovery  of  new  and  important  deposits  and  has  greatly  added
to  the  known  extent  of  the  deposits.  Lands  remaining  in  Government ­
  ownership  that  are  known  to  contain  valuable  phosphate  deposits ­
  and  those  that  are  believed  to  contain  such  deposits  have  been
temporarily  withdrawn  from  entry.  These  reserves  are  located  in
Florida,  Idaho,  Utah,  Wyoming,  and  Montana.  The  work  of  surveying ­
  the  western  phosphate  lands  is  still  going  on,  and  it  only