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  Hatcher 
  — 
  Sedimentary 
  Rocks 
  of 
  Southern 
  Patagonia. 
  

  

  Patagonian 
  beds. 
  — 
  The 
  type 
  locality 
  for 
  the 
  Patagonian 
  

   beds 
  may 
  be 
  considered 
  as 
  the 
  bluffs 
  of 
  the 
  Atlantic 
  coast 
  

   from 
  Port 
  Desire 
  southward 
  to 
  the 
  Mt. 
  of 
  Observation, 
  some 
  

   forty 
  miles 
  south 
  of 
  the 
  Santa 
  Cruz 
  River. 
  Anywhere 
  along 
  

   this 
  coast 
  within 
  these 
  limits 
  the 
  Patagonian 
  beds 
  may 
  be 
  

   found 
  well 
  represented 
  and 
  rich 
  in 
  the 
  remains 
  of 
  fossil 
  inver- 
  

   tebrates. 
  They 
  appear 
  to 
  attain 
  their 
  maximum 
  development 
  

   in 
  the 
  region 
  of 
  San 
  Julian, 
  where 
  they 
  show 
  a 
  thickness 
  

   above 
  the 
  water 
  level 
  of 
  about 
  900 
  feet. 
  From 
  this 
  point 
  

   they 
  dip 
  gently 
  to 
  the 
  southeast, 
  so 
  that 
  at 
  Coy 
  Inlet 
  their 
  

   uppermost 
  strata 
  pass 
  beneath 
  the 
  water 
  level. 
  The 
  Patago- 
  

   nian 
  beds 
  are 
  also 
  known 
  to 
  extend 
  along 
  the 
  Atlantic 
  coast 
  for 
  

   a 
  considerable 
  distance 
  north 
  of 
  Port 
  Desire, 
  and 
  are 
  found 
  

   exposed 
  in 
  many 
  localities 
  in 
  the 
  bluffs 
  of 
  the 
  streams 
  through- 
  

   out 
  the 
  interior 
  of 
  all 
  that 
  portion 
  of 
  southern 
  Patagonia 
  lying 
  

   north 
  of 
  the 
  Santa 
  Cruz 
  River. 
  They 
  may 
  also 
  be 
  seen 
  in 
  a 
  

   series 
  of 
  outcrops 
  extending 
  all 
  along 
  the 
  eastern 
  base 
  of 
  the 
  

   Andes. 
  In 
  the 
  section 
  of 
  the 
  Rio 
  de 
  las 
  Minas, 
  they 
  conform- 
  

   ably 
  overlie 
  the 
  Upper 
  Lignites. 
  They 
  also 
  appear 
  in 
  the 
  

   bluffs 
  near 
  Lakes 
  Argentina, 
  Yiedma 
  and 
  San 
  Martin, 
  at 
  Shell 
  

   Gap 
  and 
  various 
  other 
  places 
  on 
  the 
  head 
  of 
  the 
  Rio 
  Chico 
  

   and 
  in 
  the 
  Pueyrredon 
  and 
  Rio 
  Tarde 
  sections, 
  where 
  they 
  are 
  

   700 
  feet 
  thick 
  and 
  rest 
  directly 
  upon 
  the 
  Variegated 
  Sandstones 
  

   or 
  are 
  separated 
  from 
  the 
  latter 
  by 
  about 
  fifty 
  feet 
  of 
  col- 
  

   umnar 
  basalt. 
  The 
  entire 
  series 
  of 
  strata 
  constituting 
  the 
  Lower 
  

   Lignites, 
  Guaranitic 
  and 
  Magellanian 
  beds 
  and 
  the 
  Upper 
  

   Lignites 
  are 
  wanting 
  in 
  the 
  Pueyrredon 
  region. 
  

  

  Ameghino 
  has 
  always 
  considered 
  the 
  Patagonian 
  and 
  Supra- 
  

   Patagonian 
  beds 
  as 
  distinct 
  and 
  separated 
  by 
  a 
  considerable 
  

   period 
  of 
  time, 
  and 
  in 
  my 
  former 
  paper 
  I 
  took 
  the 
  same 
  view, 
  

   since 
  at 
  that 
  time 
  I 
  had 
  worked 
  but 
  little 
  in 
  the 
  typical 
  Pata- 
  

   gonian 
  beds. 
  During 
  the 
  last 
  two 
  years, 
  however, 
  I 
  have 
  

   given 
  considerable 
  attention 
  to 
  a 
  study 
  of 
  the 
  Patagonian 
  beds 
  

   in 
  the 
  type 
  localities, 
  and 
  have 
  made 
  extensive 
  collections 
  of 
  

   vertebrate 
  and 
  invertebrate 
  fossils 
  from 
  them 
  at 
  Port 
  San 
  

   Julian 
  and 
  Darwin 
  Station, 
  some 
  twenty 
  miles 
  south 
  of 
  that 
  

   port, 
  and 
  about 
  the 
  mouth 
  of 
  the 
  Santa 
  Cruz 
  River 
  and 
  the 
  

   Mt. 
  of 
  Observation 
  farther 
  south 
  on 
  the 
  Atlantic 
  coast. 
  These 
  

   collections 
  from 
  the 
  typical 
  Patagonian 
  beds 
  I 
  have 
  also 
  sup- 
  

   plemented 
  by 
  collections 
  made 
  at 
  many 
  different 
  localities 
  

   throughout 
  the 
  interior 
  region, 
  and 
  representing 
  every 
  con- 
  

   ceivable 
  horizon 
  from 
  the 
  base 
  to 
  the 
  top 
  of 
  the 
  so-called 
  

   Supra-Patagonian 
  beds 
  of 
  that 
  region, 
  as 
  well 
  as 
  at 
  the 
  Mt. 
  

   of 
  Observation. 
  Among 
  the 
  localities 
  from 
  which 
  such 
  col- 
  

   lections 
  were 
  made 
  I 
  may 
  mention 
  the 
  following 
  : 
  the 
  bluffs 
  of 
  

   the 
  Santa 
  Cruz 
  River, 
  source 
  of 
  Rio 
  Shehuen, 
  several 
  localities 
  

   between 
  the 
  latter 
  stream 
  and 
  the 
  Rio 
  Chico, 
  at 
  Sierra 
  Oveja 
  

  

  