﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  247 
  

  

  occur 
  in 
  the 
  Cretaceous. 
  In 
  North 
  America 
  they 
  predominate 
  in 
  the 
  Cretaceous. 
  The- 
  

   codontia 
  are 
  Triassic 
  in 
  both 
  continents 
  ; 
  and 
  the 
  Pythonomorpha 
  are 
  alike 
  Cretaceous. 
  

   The 
  serpents 
  are 
  in 
  neither 
  region 
  older 
  than 
  Eocene. 
  

  

  Among 
  Testudinata, 
  Trionyx 
  is 
  first 
  Cretaceous 
  in 
  America, 
  first 
  Eocene 
  in 
  Europe. 
  

   Chelonoid 
  Emydidse, 
  also 
  Cretaceous 
  here, 
  are 
  first 
  Jurassic 
  in 
  Europe. 
  In 
  the 
  latter 
  

   period 
  the 
  order 
  has 
  so 
  far 
  been 
  best 
  represented; 
  those 
  beds 
  are 
  rare 
  in 
  our 
  country, 
  but 
  

   if 
  present, 
  it 
  could 
  scarcely 
  be 
  more 
  abundantly 
  productive 
  of 
  them 
  than 
  is 
  our 
  Cretaceous. 
  

  

  Among 
  the 
  Crocodilia, 
  the 
  amphiccelian 
  division 
  is 
  especially 
  Jurassic, 
  not 
  occurring 
  in 
  

   the 
  Cretaceous; 
  our 
  only 
  genus 
  was 
  abundant 
  in 
  the 
  latter 
  period. 
  The 
  procoeli 
  are 
  

   characteristic 
  of 
  the 
  tertiary 
  in 
  Europe, 
  a 
  very 
  few 
  being 
  noted 
  as 
  from 
  the 
  upper 
  Cre- 
  

   taceous. 
  Here 
  their 
  chief 
  abundance 
  is 
  in 
  the 
  Cretaceous, 
  from 
  which 
  they 
  extend 
  to 
  the 
  

   present 
  time. 
  

  

  The 
  Dinosauria 
  are 
  characteristic 
  of 
  the 
  upper 
  Cretaceous 
  period 
  in 
  North 
  America, 
  

   and 
  of 
  the 
  Jurassic 
  to 
  a 
  less 
  degree. 
  In 
  Europe 
  they 
  characterize 
  the 
  Jurassic, 
  and 
  are 
  

   rare 
  in 
  the 
  Cretaceous. 
  Thus, 
  of 
  corresponding 
  genera 
  Lselaps 
  is 
  upper 
  Cretaceous, 
  Me- 
  

   galosaurus 
  and 
  Poecilopleurum, 
  Jurassic. 
  Hadrosaurus, 
  upper 
  Cretaceous 
  and 
  Jurassic; 
  

   Iguanodon, 
  Jurassic 
  and 
  lower 
  Cretaceous. 
  Astrodon 
  and 
  Hypsibema 
  middle 
  Cretaceous 
  ; 
  

   Hylseosaurus, 
  Jurassic. 
  Further, 
  we 
  have 
  evidence 
  of 
  many 
  Dinosauria 
  in 
  the 
  Trias., 
  by 
  

   their 
  foot-tracks 
  and 
  the 
  remains 
  of 
  Megadactylus, 
  Clepsysaurus 
  and 
  Bathygnathus, 
  which 
  

   are 
  nearly 
  related 
  to 
  the 
  genera 
  of 
  the 
  Trias 
  of 
  England 
  and 
  Germany. 
  

  

  STRATIGRAPHICAL 
  OBSERVATIONS. 
  

  

  I. 
  The 
  Cretaceous 
  of 
  New 
  Jersey. 
  

  

  A 
  full 
  review 
  of 
  the 
  vertebrate 
  species 
  from 
  the 
  Cretaceous 
  of 
  New 
  Jersey, 
  results 
  in 
  

   the 
  conviction 
  that 
  but 
  few 
  of 
  them 
  belong 
  to 
  types 
  which 
  are 
  necessarily 
  marine, 
  while 
  

   many 
  of 
  them 
  are 
  the 
  representatives 
  of 
  the 
  genera 
  which 
  are 
  at 
  the 
  present 
  day 
  purely 
  

   fresh-water. 
  Taking 
  them 
  seriatim, 
  it 
  is 
  obvious 
  that 
  the 
  six 
  Dinosauria 
  are 
  terrestrial, 
  

   and 
  if 
  at 
  all, 
  but 
  occasional 
  swimmers. 
  The 
  eight 
  Crocodiles 
  have 
  only 
  fresh-water 
  re- 
  

   presentatives 
  at 
  the 
  present 
  day. 
  The 
  shortness 
  of 
  the 
  limbs 
  of 
  these 
  reptiles 
  is 
  not 
  

   adapted 
  to 
  stemming 
  the 
  waves 
  of 
  the 
  open 
  ocean 
  or 
  an 
  undefended 
  coast, 
  for 
  any 
  long 
  

   period; 
  and 
  this 
  observation 
  will 
  apply 
  to 
  all 
  marine 
  vertebrates 
  with 
  separated 
  digits 
  

   whose 
  life 
  is 
  spent 
  in 
  the 
  water, 
  and 
  who 
  rely 
  on 
  their 
  limbs 
  for 
  progression, 
  unless 
  their 
  

   bulk 
  be 
  such 
  as 
  to 
  render 
  them 
  independent 
  of 
  the 
  waves, 
  or 
  they 
  are 
  furnished 
  with 
  

   wings. 
  Thus, 
  the 
  marine 
  turtles 
  possess 
  long 
  oar-like 
  limbs, 
  while 
  those 
  of 
  brackish 
  and 
  

   fresh 
  waters 
  have 
  short 
  paddles 
  of 
  far 
  less 
  power. 
  The 
  limbs 
  of 
  the 
  twenty-four 
  species 
  

   found 
  in 
  New 
  Jersey, 
  are 
  of 
  the 
  latter 
  character, 
  and 
  all 
  their 
  modern 
  representatives 
  in- 
  

  

  