MINERAL  PRODUCTS.

17

in  Arkansas,  and  the  Livermore  and  Tesla  districts  in  California.
Districts  of  minor  importance  are  the  New  River  region  in  Virginia,
the  northeastern  Tennessee  region,  the  McCormick  region  in  South
Carolina,  and  the  Little  Grande  district  in  Utah.  Mining  and  shipping ­
  in  Virginia  are  now  confined  to  the  Blue  Ridge  and  James
River-Staunton  River  regions.
Manganiferous  iron  ores  consist  of  mixtures  of  manganese  and
iron  oxides  and  hydrous  oxides,  which,  though  usually  containing
manganese  in  excess  of  5  per  cent,  may  contain  as  little  as  1  per  cent.
The  proportion  of  iron  in  such  ores  is  highly  variable,  but  usually
exceeds  40  per  cent.  Manganiferous  iron  ores  occur  in  the  United
States  chiefly  in  the  New  England,  Appalachian,  and  Lake  Superior
regions,  and  minor  deposits  are  found  in  the  southern  part  of  the
Mississippi  Valley  and  in  the  Rocky  Mountain  region.  High-grade
manganiferous  iron  ore  used  for  its  manganese  content  occurs  in
the  Appalachian  region.  Other  manganiferous  iron  ores,  which  are
so  low  in  manganese  that  they  are  classed  as  iron  ores,  are  produced
in  the  Appalachian  and  Lake  Superior  districts.  In  the  blast  furnace ­
  they  yield  a  "  high-manganese  "  pig  iron,  which  is  used  for
special  purposes.
'  Manganiferous  silver  ores  consist  of  mixtures  of  manganese  and
iron  oxides  and  hydrous  oxides,  with  small  quantities  of  silver  and
lead  minerals.  As  a  rule  the  iron  content  exceeds  the  manganese
content,  but  locally  the  iron  is  altogether  absent.
Manganiferous  silver  ores  occur  in  the  Rocky  Mountain  and
Great  Basin  regions,  the  principal  producing  locality  being  Leaded ­
  lie,  Colo.  Leadville  ores  have  been  used  in  making  spiegeleisen
from  time  to  time,  but  none  are  now  used  for  this  purpose.
Manganiferous  zinc  residuum  is  an  artificial  furnace  product  consisting ­
  of  manganese  and  iron  oxides  in  a  matrix  of  slag.  It  is
obtained  from  zinc  volatilizing  and  oxidizing  furnaces  using  New
Jersey  zinc  ores.  Small  quantities  of  zinc  residuum  are  used  annually ­
  in  the  manufacture  of  spiegeleisen.
Bulletin  427  of  the  United  States  Geological  Survey  (“  Manganese
Deposits  of  the  United  States,”  by  E.  C.  Harder),  which  is  still
available  for  free  distribution,  contains  brief  descriptions  of  most
of  the  known  deposits  of  manganese  in  this  country  and  the  important ­
  deposits  of  other  countries,  and  concise  summaries  of  the  chemistry ­
  and  mineralogy  of  manganese.
ZINC.
By  a  queer  coincidence  the  great  smelting  centers  of  continental
Europe  are  in  regions  where  active  fighting  is  now  going  on  or  may
be  expected  in  the  near  future.  The  zinc  smelters  of  Upper  Silesia
are  in  the  extreme  southeastern  portion  of  Prussia,  mostly  in  the
50170°—Bull.  599—14  2