﻿GEOLOGY. 
  209 
  

  

  undations 
  and 
  atmospheric 
  irregularities 
  to 
  be 
  occupied, 
  

   to 
  much 
  extent, 
  by 
  a 
  higher 
  order 
  of 
  beings. 
  

  

  With 
  this 
  period, 
  also, 
  two 
  distinct 
  assemblages 
  of 
  

   terrestrial 
  plants 
  appear 
  to 
  have 
  flourished 
  and 
  become 
  

   extinct, 
  embracing 
  the 
  flora 
  of 
  the 
  Carboniferous 
  era. 
  

   With 
  the 
  cretaceous 
  system 
  (including 
  the 
  Maestricht 
  

   beds), 
  which 
  sometimes 
  connects 
  it 
  with 
  the 
  succeeding 
  

   formation, 
  ends 
  the 
  series 
  of 
  deposits 
  which 
  are 
  ranked 
  

   as 
  strata 
  of 
  the 
  Secondary 
  period 
  of 
  geology. 
  

  

  The 
  Tertiary 
  formation 
  comprehends 
  all 
  those 
  varied 
  

   stratiform 
  deposits, 
  more 
  recent 
  than 
  the 
  Secondary, 
  

   which 
  underlie 
  the 
  modern 
  group, 
  and 
  are 
  characterized 
  

   by 
  distinct 
  species 
  of 
  fossil 
  animals 
  and 
  plants 
  ; 
  present- 
  

   ing 
  the 
  striking 
  feature 
  of 
  repeated 
  alternations 
  of 
  

   marine 
  deposits 
  and 
  those 
  of 
  fresh 
  water. 
  

  

  During 
  this 
  period, 
  there 
  appears 
  to 
  have 
  been 
  a 
  con- 
  

   stantly 
  increasing 
  provision 
  for 
  the 
  diffusion 
  of 
  animal 
  

   life. 
  Its 
  most 
  ancient 
  deposits 
  contain 
  organic 
  remains 
  

   related 
  to 
  those 
  of 
  the 
  Secondary 
  period, 
  and 
  the 
  most 
  

   recent 
  contain 
  many 
  existing 
  species 
  of 
  animals 
  asso- 
  

   ciated 
  with 
  forms 
  now 
  extinct. 
  

  

  Mr. 
  Lyell 
  has 
  subdivided 
  the 
  Tertiary 
  into 
  the 
  

   Eocine, 
  the 
  Meocine, 
  and 
  the 
  older 
  and 
  the 
  newer 
  Plio- 
  

   cene, 
  founded 
  on 
  the 
  relative 
  proportions 
  of 
  the 
  extinct 
  

   and 
  recent 
  species 
  of 
  shells 
  which 
  they 
  contain. 
  In 
  

   these 
  divisions 
  are 
  found 
  also 
  the 
  unconsolidated 
  rocks, 
  

   such 
  as 
  the 
  sands, 
  clays, 
  and 
  marls, 
  as 
  well 
  as 
  lignites 
  

   and 
  conglomerates. 
  

  

  Above 
  these 
  principal 
  divisions 
  we 
  have 
  the 
  Quater- 
  

   nary, 
  embracing 
  the 
  modern 
  group 
  " 
  to 
  which 
  belong 
  all 
  

   those 
  formations 
  now 
  completed, 
  or 
  in 
  progress, 
  upon 
  

   the 
  face 
  of 
  the 
  earth 
  or 
  in 
  its 
  waters, 
  which 
  contain 
  the 
  

   remains 
  of 
  man, 
  or 
  of 
  his 
  works, 
  or 
  the 
  remains 
  of 
  

   14 
  

  

  