﻿264 
  S. 
  Roth 
  — 
  Some 
  remarks 
  on 
  the 
  latest 
  

  

  near 
  the 
  Li 
  may 
  four 
  times, 
  and 
  have 
  never 
  seen 
  a 
  trace 
  of 
  

   marine 
  deposits, 
  and 
  the 
  same 
  results 
  have 
  been 
  obtained 
  by 
  

   Drs. 
  Moreno, 
  Wehrli, 
  Zabalowicz, 
  Siemiradzki 
  and 
  others. 
  On 
  

   the 
  Pichipicuru 
  Leufu, 
  Mr. 
  Hauthal 
  has 
  met 
  with 
  marine 
  

   deposits 
  in 
  the 
  upper 
  part 
  ; 
  these, 
  however, 
  belong 
  to 
  the 
  

   Lower 
  Cretaceous 
  and 
  have 
  nothing 
  in 
  common 
  with 
  those 
  

   from 
  Roca. 
  On 
  the 
  Rio 
  Collon 
  Cura 
  itself 
  there 
  are 
  — 
  as 
  far 
  as 
  

   it 
  has 
  been 
  explored 
  — 
  no 
  marine 
  deposits 
  ; 
  but 
  such 
  deposits 
  

   are 
  present 
  in 
  what 
  is 
  called 
  Angostura, 
  several 
  hours 
  distant 
  

   from 
  the 
  river. 
  These, 
  however, 
  are 
  of 
  Jurassic 
  age 
  (Lias). 
  

   These 
  two 
  marine 
  deposits 
  are 
  no 
  doubt 
  much 
  older 
  than 
  those 
  

   near 
  Roca, 
  and 
  it 
  is 
  impossible 
  that 
  they 
  belong 
  to 
  one 
  and 
  the 
  

   same 
  stage. 
  Upon 
  what 
  grounds 
  Ameghino 
  places 
  the 
  marine 
  

   beds 
  of 
  Roca 
  in 
  his 
  Piso 
  Sehuense, 
  does 
  not 
  appear 
  in 
  his 
  paper. 
  

  

  3. 
  Regarding 
  the 
  Tertiary 
  tufa-deposits 
  on 
  the 
  Collon 
  Cura 
  

   discovered 
  by 
  me, 
  he 
  says 
  that 
  they 
  belong 
  to 
  the 
  Patagonian 
  

   formation. 
  As 
  to 
  the 
  latter, 
  so 
  much 
  confusion 
  prevails, 
  that 
  a 
  

   more 
  extended 
  discussion, 
  than 
  is 
  now 
  possible, 
  would 
  be 
  neces- 
  

   sary 
  to 
  determine 
  the 
  validity 
  of 
  this 
  correlation. 
  It 
  is 
  suffi- 
  

   cient 
  to 
  remark, 
  that 
  the 
  tufas 
  in 
  question 
  are 
  of 
  the 
  same 
  age 
  

   as 
  the 
  marine 
  beds 
  on 
  the 
  coast 
  near 
  the 
  mouth 
  of 
  the 
  Rio 
  

   Chubut, 
  and 
  that 
  in 
  both 
  the 
  same 
  mammalian 
  remains 
  are 
  

   found 
  as 
  in 
  the 
  Santacruzian. 
  Ameghino 
  bases 
  his 
  opinion, 
  

   that 
  the 
  tufas 
  of 
  Collon 
  Cura 
  are 
  older 
  than 
  the 
  Santa-Cruz- 
  

   beds, 
  on 
  the 
  fact 
  that 
  remains 
  of 
  Propachyrucos 
  and 
  Etctrachy- 
  

   theres 
  are 
  present 
  in 
  them, 
  which 
  he 
  regards 
  as 
  characteristic 
  

   Cretaceous 
  mammals. 
  Eutrachytheres, 
  however, 
  or 
  at 
  least 
  a 
  

   very 
  closely 
  allied 
  genus 
  of 
  the 
  family 
  Typotheridce, 
  is 
  found 
  

   in 
  Patagonia 
  in 
  very 
  much 
  younger 
  deposits, 
  from 
  which 
  we 
  

   have 
  secured 
  several 
  species 
  of 
  the 
  genus 
  Toxodon 
  and 
  a 
  

   species 
  of 
  Megatherium. 
  Propachyrucos 
  is 
  so 
  closely 
  allied 
  

   to 
  Pachyrucos, 
  found 
  abundantly 
  in 
  the 
  lower 
  Pampean 
  beds, 
  

   that 
  its 
  presence 
  in 
  the 
  Santacruzian 
  is 
  not 
  at 
  all 
  strange. 
  The 
  

   very 
  presence 
  of 
  these 
  two 
  genera, 
  so 
  highly 
  specialized, 
  in 
  the 
  

   so-called 
  Pyrotherium 
  fauna, 
  is 
  an 
  argument 
  for 
  the 
  young 
  age 
  

   of 
  the 
  latter, 
  and 
  if 
  it 
  were 
  not 
  for 
  some 
  more 
  primitive 
  forms 
  

   associated 
  with 
  them, 
  we 
  could 
  agree 
  with 
  Mr. 
  Hatcher's 
  

   opinion, 
  that 
  the 
  Pyrotherium 
  fauna 
  is 
  younger 
  than 
  the 
  Santa- 
  

   cruzian. 
  But, 
  as 
  is 
  shown 
  by 
  stratigraphical 
  evidence, 
  it 
  is 
  

   really 
  older 
  than 
  the 
  latter. 
  

  

  4. 
  The 
  sandstone-formation 
  of 
  the 
  Rio 
  Negro, 
  which 
  has 
  

   been 
  described 
  carefully 
  by 
  Zapalowicz* 
  and 
  myself,f 
  is 
  placed 
  

   by 
  Ameghino 
  in 
  the 
  Piso 
  Rionegrense, 
  which 
  he 
  believes 
  to 
  

   be 
  Lower 
  Miocene. 
  Apparently 
  his 
  reason 
  for 
  this 
  is, 
  that 
  he 
  

   confuses 
  the 
  sandstone 
  formation 
  with 
  the 
  marine 
  deposits, 
  

   which 
  are 
  exposed 
  in 
  some 
  places 
  near 
  Carmen 
  de 
  Patagones. 
  

  

  *Das 
  Rio 
  Negro 
  Gebiet 
  in 
  Patagonien. 
  Denkschr. 
  k. 
  Akad. 
  Wiss. 
  Wien 
  , 
  1893. 
  

   f 
  Apuntes 
  sobra 
  la 
  Geologia, 
  etc., 
  1898. 
  

  

  