﻿104 
  Hatcher 
  — 
  Sedimentary 
  Rocks 
  of 
  Southern 
  Patagonia. 
  

  

  this 
  discrepancy 
  on 
  the 
  part 
  of 
  Dr. 
  Ameghino 
  is 
  largely 
  due 
  

   the 
  conflicting 
  opinions 
  at 
  present 
  expressed 
  by 
  him 
  concern- 
  

   ing 
  the 
  age 
  of 
  these 
  various 
  deposits. 
  

  

  The 
  Patagonian 
  beds 
  are 
  here 
  placed 
  in 
  the 
  Upper 
  Oligocene 
  

   and 
  Lower 
  Miocene 
  on 
  account 
  of 
  the 
  evidences 
  afforded 
  by 
  

   the 
  marine 
  invertebrates 
  found 
  in 
  them. 
  Moericke, 
  Steinmann, 
  

   Cossmann, 
  Dall 
  and 
  others, 
  all 
  of 
  whom 
  have 
  studied 
  more 
  or 
  

   less 
  material 
  from 
  these 
  beds, 
  are 
  agreed 
  in 
  placing 
  them 
  in 
  

   the 
  Miocene. 
  Dr. 
  A. 
  E. 
  Ortmann, 
  who 
  is 
  studying 
  our 
  collec- 
  

   tions 
  in 
  which 
  there 
  is 
  represented 
  much 
  the 
  most 
  complete 
  

   series 
  yet 
  brought 
  together 
  from 
  the 
  Tertiaries 
  of 
  Patagonia, 
  

   is 
  convinced 
  that 
  they 
  are 
  not 
  older 
  than 
  uppermost 
  Oligocene, 
  

   and 
  that 
  they 
  are 
  chiefly 
  Miocene. 
  Dr. 
  von 
  Ihering, 
  who 
  

   studied 
  the 
  collections 
  of 
  Carlos 
  Ameghino, 
  relying 
  upon 
  his 
  

   and 
  Dr. 
  Ameghino's 
  stratigraphic 
  determinations 
  and 
  differ- 
  

   entiations, 
  which 
  as 
  has 
  been 
  shown 
  are 
  only 
  local 
  develop- 
  

   ments 
  and 
  do 
  not 
  represent 
  distinct 
  horizons, 
  has 
  referred 
  the 
  

   Patagonian 
  beds 
  to 
  the 
  Upper 
  Eocene 
  and 
  the 
  so-called 
  Supra- 
  

   Patagonian 
  beds 
  to 
  the 
  Oligocene 
  and 
  Lower 
  Miocene. 
  Dr. 
  

   Ameghino 
  has 
  himself 
  considered 
  the 
  Patagonian 
  beds 
  as 
  

   belonging 
  to 
  the 
  Upper 
  Cretaceous 
  and 
  Lower 
  Eocene, 
  assign- 
  

   ing 
  them 
  this 
  position, 
  apparently, 
  in 
  order 
  to 
  accommodate 
  his 
  

   theory 
  concerning 
  the 
  great 
  antiquity 
  of 
  the 
  overlying 
  Santa 
  

   Cruz 
  beds. 
  

  

  In 
  connection 
  with 
  the 
  age 
  of 
  the 
  Patagonian 
  beds 
  it 
  is 
  

   interesting 
  to 
  note 
  the 
  remarkably 
  close 
  relationship 
  existing 
  

   between 
  this 
  invertebrate 
  fauna 
  and 
  the 
  invertebrates 
  from 
  the 
  

   Oamaru 
  and 
  Pareora 
  Systems 
  of 
  New 
  Zealand, 
  which 
  latter, 
  

   according 
  to 
  Hutton, 
  belong 
  respectively 
  to 
  the 
  Oligocene 
  

   and 
  Miocene. 
  Dr. 
  Ortmann 
  has 
  already 
  found 
  the 
  following 
  

   twelve 
  identical 
  species 
  : 
  Rhynchonella 
  squamosa 
  Hutt. 
  (=cos- 
  

   tata 
  Ten. 
  Wood 
  = 
  pyxidata 
  Dav.), 
  R. 
  nigricans 
  (Sow.) 
  (=pli- 
  

   cigera 
  v. 
  Ihr.), 
  Magellania 
  lenticularis 
  (Desh.) 
  (=globosa 
  v. 
  

   Ihr), 
  Terebratella 
  dorsata 
  (Gmel.), 
  Terebratella 
  patagonica 
  

   (Sow.), 
  Ostrea 
  ingens 
  Zitt. 
  (=patagonica 
  Aut. 
  non 
  d'Orb.= 
  

   percrassa 
  v. 
  Ihr. 
  = 
  hatcheri 
  and 
  phillippi 
  Ortm.), 
  Cucullcea 
  alia 
  

   Sow., 
  Zimopsis 
  insolita 
  (Sow.), 
  Dentalium 
  giganteum 
  Sow., 
  

   Scalaria 
  rugulosa 
  Sow. 
  (=lyrata 
  and 
  browni 
  Zitt.), 
  Orepidula 
  

   gregaria 
  Sow. 
  (=incurva 
  Zitt.), 
  Natica 
  solida 
  Sow., 
  and 
  he 
  

   informs 
  me 
  that 
  this 
  list 
  will 
  be 
  very 
  much 
  increased 
  and 
  that 
  

   many 
  other 
  species, 
  while 
  not 
  precisely 
  identical, 
  show 
  remarka- 
  

   bly 
  close 
  relationships. 
  The 
  affinities 
  exhibited 
  by 
  these 
  two 
  

   faunas 
  are 
  of 
  interest 
  not 
  only 
  for 
  the 
  evidence 
  they 
  afford 
  

   concerning 
  the 
  age 
  of 
  the 
  Patagonian 
  beds, 
  but 
  also 
  on 
  account 
  

   of 
  the 
  additional 
  proof 
  they 
  furnish 
  in 
  favor 
  of 
  the 
  theory 
  of 
  

   a 
  former 
  land, 
  or 
  at 
  least 
  exceedingly 
  shallow 
  sea, 
  connecting 
  

   New 
  Zealand 
  and 
  other 
  austral 
  lands 
  with 
  South 
  America. 
  

  

  