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  ISEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Life 
  of 
  the 
  Triassic 
  period 
  

  

  In 
  the 
  Triassic 
  was 
  the 
  reign 
  of 
  the 
  amphibians, 
  some 
  of 
  which 
  

   were 
  very 
  large. 
  The 
  most 
  highly 
  developed 
  was 
  the 
  labyrin- 
  

   thodon, 
  which 
  had 
  the 
  form 
  of 
  a 
  frog 
  and 
  was 
  as 
  large 
  as 
  an 
  ox. 
  

   Reptiles 
  were 
  very 
  large 
  and 
  numerous 
  but 
  their 
  remains 
  are 
  

   more 
  abundant 
  in 
  Europe 
  than 
  America. 
  The 
  mammalian 
  fauna 
  

   was 
  insignificant; 
  fishes 
  were 
  numerous; 
  mollusks 
  were 
  abun- 
  

   dant, 
  but 
  were 
  not 
  a 
  prevailing 
  type. 
  

  

  JURASSIC 
  SYSTEM 
  

  

  The 
  connection 
  between 
  the 
  Triassic 
  and 
  Jurassic 
  is 
  very 
  close 
  

   and 
  the 
  passage 
  is 
  very 
  gradual. 
  The 
  Jurassic 
  takes 
  its 
  name 
  

   from 
  the 
  Jura 
  mountains 
  of 
  France 
  and 
  Switzerland, 
  which 
  are 
  

   chiefly 
  composed 
  of 
  the 
  rocks 
  of 
  this 
  age. 
  In 
  eastern 
  North 
  

   America 
  the 
  Jurassic 
  is 
  moderately 
  developed, 
  and 
  it 
  is 
  con- 
  

   sidered 
  that 
  a 
  part 
  of 
  the 
  Triassic 
  sandstone, 
  already 
  described, 
  

   may 
  have 
  been 
  deposited 
  during 
  this 
  age. 
  

  

  West 
  of 
  the 
  Mississippi 
  the 
  Jurassic 
  is 
  well 
  developed. 
  

  

  Life 
  of 
  the 
  Jurassic 
  period 
  

  

  The 
  Jurassic 
  was 
  especially 
  characterized 
  by 
  the 
  prominence 
  

   of 
  reptilian 
  life 
  which 
  appeared 
  in 
  a 
  great 
  variety 
  of 
  forms 
  

   nnd 
  occupied 
  every 
  place 
  in 
  nature. 
  Reptiles 
  were 
  large 
  and 
  

   numerous, 
  in 
  the 
  ocean 
  and 
  on 
  land. 
  Even 
  in 
  the 
  air 
  immense 
  

   lizards 
  vrith 
  wings 
  like 
  those 
  of 
  a 
  bat 
  were 
  abundant. 
  In 
  this 
  

   age 
  the 
  first 
  of 
  the 
  birds 
  appears. 
  This 
  was 
  the 
  archaeopteryx, 
  

   found 
  in 
  the 
  slates 
  of 
  Solenhofen, 
  Germany, 
  a 
  bird 
  which 
  was 
  

   rudimentary 
  in 
  its 
  development. 
  The 
  wings 
  were 
  short 
  and 
  also 
  

   the 
  wing 
  feathers 
  which 
  v/ere 
  radiated. 
  The 
  tail 
  was 
  vertebrated 
  

   and 
  the 
  vertebrae 
  bore 
  feathers. 
  It 
  had 
  no 
  teeth. 
  The 
  sharks 
  

   and 
  ganoid 
  fishes 
  were 
  large 
  and 
  abundant. 
  The 
  mammals 
  were 
  

   numerous, 
  but 
  subordinate 
  in 
  rank, 
  not 
  being 
  larger 
  than 
  rats 
  

   and 
  opossums. 
  

  

  In 
  this 
  system 
  also 
  was 
  the 
  culmination 
  of 
  the 
  ammonite 
  fam- 
  

   ily, 
  a 
  group 
  of 
  coiled 
  cephalopoda 
  named 
  from 
  their 
  resemblance 
  

   to 
  the 
  horns 
  on 
  the 
  statues 
  of 
  Jupiter 
  Ammon. 
  As 
  the 
  cephalo- 
  

  

  