﻿86 
  Hatcher 
  — 
  Sedimentary 
  Rocks 
  of 
  Southern 
  Patagonia. 
  

  

  ous 
  sedimentary 
  deposits 
  as 
  expressed 
  in 
  my 
  forme 
  paper 
  are 
  : 
  

   First, 
  the 
  age 
  of 
  the 
  Patagonian 
  beds. 
  A 
  study 
  of 
  the 
  very 
  

   extensive 
  collections 
  of 
  invertebrate 
  fossils 
  which 
  we 
  now 
  pos- 
  

   sess 
  from 
  the 
  typical 
  Patagonian 
  beds 
  makes 
  it 
  necessary 
  ta 
  

   remove 
  this 
  entire 
  series 
  of 
  strata 
  from 
  the 
  Eocene, 
  where 
  we 
  

   had 
  formerly 
  placed 
  it, 
  and 
  to 
  refer 
  the 
  rocks 
  composing 
  them 
  

   to 
  late 
  Oligocene 
  and 
  early 
  Miocene. 
  Second, 
  extensive 
  

   observations 
  in 
  the 
  Patagonian 
  and 
  Supra- 
  Patagonian 
  beds 
  

   at 
  many 
  different 
  and 
  widely 
  separated 
  localities, 
  has 
  demon- 
  

   strated 
  beyond 
  a 
  doubt 
  the 
  identity 
  of 
  these 
  two 
  deposits, 
  

   which 
  were 
  formerly 
  supposed 
  to 
  be 
  quite 
  distinct 
  and 
  sepa- 
  

   rated 
  by 
  a 
  considerable 
  period 
  of 
  time. 
  Third, 
  an 
  interstrati- 
  

   fication 
  has 
  been 
  observed 
  between 
  the 
  upper 
  Supra-Patagonian 
  

   and 
  lower 
  Santa 
  Cruz 
  beds. 
  This 
  condition 
  was 
  first 
  noticed 
  

   and 
  has 
  always 
  been 
  maintained 
  by 
  Florentino 
  and 
  Carlos 
  

   Ameghino. 
  It 
  was 
  erroneously 
  opposed 
  by 
  myself 
  in 
  my 
  for- 
  

   mer 
  paper, 
  due 
  to 
  insufficient 
  observations 
  on 
  my 
  part 
  at 
  that 
  

   time. 
  

  

  These 
  additional 
  observations 
  and 
  necessary 
  corrections 
  to 
  

   my 
  first 
  paper, 
  together 
  with 
  many 
  other 
  observations 
  of 
  

   scarcely 
  less 
  importance 
  made 
  during 
  the 
  past 
  two 
  years, 
  ren- 
  

   der 
  it 
  advisable 
  to 
  record 
  here 
  the 
  principal 
  geologic 
  features 
  

   observed, 
  and 
  to 
  give 
  a 
  correlation 
  of 
  the 
  various 
  sedimentary 
  

   rocks 
  now 
  known 
  in 
  southern 
  Patagonia 
  based 
  upon 
  our 
  

   present 
  more 
  advanced 
  study 
  of 
  the 
  fossils 
  found 
  in 
  them 
  and 
  

   upon 
  a 
  comparison 
  of 
  these 
  fossils 
  with 
  fossil 
  forms 
  from 
  

   North 
  America 
  and 
  Europe 
  found 
  in 
  beds 
  the 
  age 
  of 
  which 
  

   has 
  been 
  determined 
  beyond 
  a 
  reasonable 
  doubt 
  both 
  from 
  

   paleontologic 
  and 
  stratigraphic 
  evidences. 
  

  

  It 
  will 
  be 
  the 
  purpose 
  of 
  the 
  present 
  paper 
  to 
  give 
  a 
  brief 
  

   description 
  of 
  the 
  geology 
  of 
  southern 
  Patagonia, 
  together 
  with 
  

   a 
  short 
  discussion 
  of 
  the 
  age 
  of 
  the 
  various 
  sedimentary 
  

   deposits 
  found 
  there. 
  A 
  more 
  detailed 
  treatment 
  of 
  the 
  geog- 
  

   raphy, 
  topography, 
  stratigraphy 
  and 
  general 
  geology 
  of 
  the 
  

   region 
  in 
  question 
  will 
  be 
  reserved 
  for 
  chapters 
  under 
  those 
  

   heads, 
  which 
  will 
  appear 
  in 
  one 
  of 
  a 
  series 
  of 
  monographs 
  to 
  be 
  

   issued 
  by 
  the 
  department 
  of 
  geology 
  and 
  paleontology 
  of 
  

   Princeton 
  University 
  npon 
  the 
  natural 
  history 
  collections 
  made 
  

   by 
  the 
  University 
  expeditions 
  to 
  Patagonia. 
  This 
  series 
  of 
  

   monographs 
  is 
  now 
  in 
  preparation, 
  most 
  of 
  the 
  material 
  having 
  

   already 
  been 
  placed 
  in 
  the 
  hands 
  of 
  competent 
  specialists 
  in 
  

   each 
  department. 
  Its 
  early 
  publication 
  in 
  a 
  creditable 
  manner 
  

   has 
  been 
  made 
  possible 
  by 
  the 
  munificence 
  of 
  a 
  friend 
  of 
  

   science. 
  

  

  That 
  portion 
  of 
  Patagonia 
  of 
  which 
  it 
  is 
  the 
  purpose 
  of 
  this 
  

   paper 
  to 
  treat 
  lies 
  beyond 
  the 
  46th 
  parallel 
  of 
  south 
  latitude. 
  

   A 
  map 
  of 
  the 
  region, 
  including 
  Tierra 
  del 
  Fuego 
  and 
  the 
  

  

  