﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  6j 
  

  

  development. 
  During 
  this 
  era 
  the 
  great 
  dinosaur 
  reptiles, 
  the 
  largest 
  

   land 
  animals 
  that 
  every 
  lived, 
  stalked 
  the 
  western 
  plains. 
  Some 
  

   remains 
  of 
  smaller 
  dinosaurs 
  have 
  been 
  found 
  in 
  the 
  Triassic 
  beds 
  

   of 
  the 
  Atlantic 
  coast, 
  one 
  specimen 
  lately 
  having 
  been 
  discovered 
  

   in 
  the 
  Newark 
  beds 
  along 
  the 
  lower 
  Hudson. 
  Reptilian 
  tracks 
  

   abound 
  in 
  the 
  Newark 
  strata. 
  Mammals 
  appeared 
  in 
  the 
  early 
  

   Mesozoic, 
  but 
  throughout 
  the 
  era 
  they 
  continued 
  small 
  and 
  com- 
  

   paratively 
  insignificant. 
  The 
  first 
  birds 
  and 
  true 
  bony 
  fishes 
  

   (teleosts) 
  appeared 
  in 
  the 
  later 
  Mesozoic, 
  but 
  they 
  are 
  either 
  absent 
  

   or 
  not 
  important 
  in 
  the 
  Mesozoic 
  of 
  the 
  middle 
  Atlantic 
  coast. 
  The 
  

   invertebrate 
  life 
  of 
  the 
  era 
  was 
  in 
  general 
  very 
  different 
  from 
  that 
  

   of 
  the 
  Paleozoic, 
  few 
  types 
  from 
  the 
  latter 
  era 
  having 
  persisted, 
  

   and 
  by 
  the 
  end 
  of 
  the 
  Mesozoic 
  the 
  invertebrates 
  took 
  on 
  a 
  decidedly 
  

   modern 
  aspect. 
  

  

  Among 
  plants, 
  those 
  of 
  the 
  early 
  era 
  were 
  still 
  simple 
  nonflower- 
  

   ing 
  kinds 
  much 
  like 
  those 
  of 
  the 
  Carbonic 
  or 
  " 
  Coal 
  age," 
  while 
  in 
  

   the 
  late 
  Mesozoic 
  flowering 
  plants 
  of 
  very 
  modern 
  types, 
  including 
  

   many 
  of 
  our 
  present 
  forest 
  trees, 
  were 
  prominently 
  developed. 
  The 
  

   Cretacic 
  beds 
  of 
  the 
  Atlantic 
  coast 
  are 
  rich 
  in 
  fossil 
  plants. 
  

  

  THE 
  CRETACIC 
  PENEPLAIN 
  AND 
  ITS 
  UPLIFT 
  

  

  During 
  all 
  the 
  Mesozoic 
  era 
  most 
  of 
  the 
  eastern 
  portion 
  of 
  the 
  

   United 
  States 
  was 
  above 
  water 
  and 
  undergoing 
  erosion, 
  so 
  that, 
  

   as 
  a 
  result 
  of 
  this 
  very 
  long 
  period 
  of 
  wear, 
  the 
  region 
  was 
  reduced 
  

   to 
  the 
  condition 
  of 
  a 
  more 
  or 
  less 
  perfect 
  peneplain. 
  It 
  is 
  known 
  

   as 
  the 
  Cretacic 
  peneplain 
  because 
  of 
  its 
  best 
  development 
  during 
  

   the 
  Cretacic 
  period. 
  This 
  vast 
  plain 
  extended 
  over 
  the 
  areas 
  of 
  the 
  

   Appalachian 
  mountains, 
  Piedmont 
  plateau, 
  all 
  New 
  York 
  State, 
  

   the 
  Berkshire 
  hills, 
  and 
  the 
  Green 
  mountains. 
  Its 
  most 
  perfect 
  

   development 
  was 
  in 
  the 
  northern 
  Appalachians, 
  for 
  example, 
  from 
  

   east-central 
  Pennsylvania 
  to 
  Virginia, 
  where 
  hard 
  and 
  soft 
  rocks 
  

   alike 
  had 
  been 
  so 
  thoroughly 
  cut 
  down 
  that 
  no 
  masses 
  projected 
  

   notably 
  above 
  the 
  level 
  of 
  the 
  low-lying 
  plain. 
  

  

  Farther 
  northward, 
  however, 
  over 
  New 
  York 
  and 
  western 
  New 
  

   England, 
  its 
  development 
  was 
  less 
  perfect 
  so 
  that 
  certain 
  masses 
  of 
  

   harder 
  rock 
  stood 
  out 
  more 
  or 
  less 
  prominently 
  above 
  the 
  general 
  

   level 
  of 
  the 
  plain. 
  In 
  the 
  central 
  and 
  eastern 
  Adirondacks 
  many 
  

   low 
  mountains 
  of 
  very 
  resistant 
  igneous 
  rock 
  rose 
  above 
  the 
  pene- 
  

   plain 
  surface. 
  In 
  a 
  similar 
  manner 
  an 
  occasional 
  low 
  mountain 
  

   stood 
  out 
  in 
  the 
  Berkshire 
  Hills 
  region, 
  and 
  it 
  seems 
  probable 
  that 
  

   the 
  hard 
  Devonic 
  sandstones 
  of 
  the 
  Catskills 
  also 
  rose 
  notably 
  above 
  

   the 
  peneplain, 
  though 
  in 
  the 
  latter 
  case 
  positive 
  proof 
  has 
  not 
  been 
  

   3 
  

  

  