222  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
The  Permian  in  the  Mansfeld  region  of  middle  Germany  consists 
of  barren  red  sandstones  and  conglomerates  (Rothliegende)  below 
and  limestones  (Zechstein)  above  the  copper-bearing  shales  (Kup- 
ferschiefer). 
In  the  "  Red  Bed  "  development  of  either  formation  in  all  parts  of 
the  world  there  is,  however,  a  strong  resemblance  in  the  sediments  of 
which  they  are  composed,  and  hence,  presumably,  in  the  conditions 
that  prevailed  during  sedimentation,  so  that  for  present  purposes 
it  is  relatively  unimportant  whether  the  deposits  under  consideration 
belong  more  properly  to  one  or  the  other  of  these  two  series.  The 
conditions  referred  to  are  an  abundance  of  coarse  material,  frequent 
cross-bedding,  ripple  marks,  and  raindrop  impressions,  and  a  great 
abundance  of  plant  remains,  indicating  shallow-water  deposition  in 
the  vicinity  of  land  masses.  The  frequent  occurrence  of  interbedded 
deposits  of  rock  salt,  gypsum,  and  other  soluble  salts  points,  more- 
over, to  deposition  in  more  or  less  closed  seas,  and  the  prevailing  red 
color  to  climatic  conditions  favoring  oxidation  of  the  iron-bearing 
constituents,  hence  chemical  activity  in  general. 
The  most  famous  copper  deposits  in  these  beds  are  those  of  Man*- 
feld,  in  Germany,  which  have  been  worked  for  about  TOO  years  and 
are  still  producing  about  $5,000,000  worth  of  metal  annually.  There 
the  copper  occurs  finely  disseminated  in  the  lower  2  feet  of  the  Zech- 
stein formation,  the  ore-bearing  seam  rarely  exceeding  10  inches  in 
thickness  and  carrying  on  an  average  about  2  per  cent  of  copper  with 
a  little  silver.    Some  nickel  and  lead  are  associated  with  the  deposits. 
The  Permian  in  many  other  parts  of  Germany,  in  northeastern 
Bohemia,  and  notably  on  the  west  flank  of  the  Urals,  in  Russia,  car- 
ries copper  ore  in  workable  quantities,  in  all  cases  associated  with 
plant  remains. 
In  Alsace-Lorraine  it  is  the  Triassic  sandstones  that  carry  copper 
under  similar  conditions.  In  Bolivia,  at  Corocoro  and  Cobrizos, 
argentiferous  copper  ores  are  worked  in  Permian  sandstones  that 
carry  gypsum  and  some  rock  salt.  As  reported  by  David  Forbes, 
however,  these  deposits  are  in  a  region  in  which  igneous  action  has 
been  very  active  and  the  beds  in  which  the  copper  occurs  are  much 
folded  and  disturbed.  The  ore  occurs  in  several  successive  sandstone 
strata,  upturned  at  tolerably  steep  angles,  which  are  hence  called  by 
the  miner  "  veins." 
In  this  country  copper  ores  have  been  worked  at  man}^  points  in  the 
red  sandstones  of  the  Appalachian  system,  generally  classed  as 
"  Trias,"  notably  in  Nova  Scotia  and  northern  New  Jersey,  while 
their  occurrence  in  limited  amount  in  these  sandstones  is  very  wide- 
spread. In  the  West  they  have  been  noted  over  large  areas  in  the 
red-sandstone  formations  of  western  Texas,  New  Mexico,  and  the 
