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  OF 
  SCIENCES. 
  419 
  

  

  The 
  Eocene 
  Epoch 
  in 
  California.— 
  Are 
  there 
  Really 
  no 
  Eocene 
  

   Strata 
  ? 
  

  

  BY 
  DR. 
  J. 
  G. 
  COOPER. 
  

  

  In 
  describing 
  the 
  miocene 
  formations 
  of 
  California, 
  I 
  made 
  the 
  remark 
  that 
  

   no 
  positively 
  eocene 
  fossils 
  had 
  been 
  found 
  here, 
  either 
  marine 
  or 
  terrestrial, 
  in- 
  

   dicating 
  a 
  wide 
  gap 
  in 
  the 
  early 
  tertiary 
  age. 
  Two 
  explanations 
  of 
  this 
  have 
  

   been 
  suggested. 
  One 
  is, 
  that 
  the 
  land 
  embraced 
  in 
  our 
  limits 
  was 
  entirely 
  above 
  

   the 
  ocean 
  during 
  that 
  epoch, 
  so 
  that 
  no 
  marine 
  deposits 
  could 
  be 
  formed 
  on 
  it. 
  

   But, 
  if 
  so, 
  the 
  land 
  must 
  have 
  been 
  so 
  extensive 
  that 
  it 
  would 
  almost 
  certainly 
  

   have 
  had 
  a 
  fauna 
  and 
  6ora, 
  like 
  those 
  so 
  richly 
  stored 
  up 
  in 
  the 
  Rocky 
  Mountaio 
  

   eocene, 
  and 
  traces 
  of 
  them 
  would 
  surely 
  be 
  found 
  fossil. 
  

  

  The 
  second 
  theory 
  is, 
  that 
  the 
  present 
  dry 
  land 
  was 
  then 
  sunk 
  so 
  deep 
  beneath 
  

   the 
  ocean 
  that 
  such 
  marine 
  animals 
  as 
  live 
  near 
  the 
  shore?, 
  and 
  have 
  furnished 
  

   most 
  of 
  the 
  fossils 
  in 
  other 
  formations, 
  could 
  not 
  exist, 
  or 
  that 
  the 
  rapid 
  sinking 
  

   of 
  the 
  rich 
  cretaceous 
  shores 
  caused 
  so 
  rapid 
  a 
  deposit 
  of 
  sand 
  and 
  mud 
  to 
  ac- 
  

   cumulate, 
  that 
  marine 
  animals 
  could 
  not 
  flourish. 
  There 
  is 
  some 
  proof 
  that 
  this 
  

   might 
  have 
  been 
  the 
  case, 
  in 
  the 
  fact 
  that 
  we 
  find 
  great 
  thicknesses 
  of 
  shales 
  

   and 
  sandstones, 
  above 
  the 
  so-called 
  cretaceous 
  fossils, 
  with 
  no 
  fossils 
  in 
  them 
  

   except 
  obscure 
  marks, 
  like 
  tracks 
  or 
  burrows 
  of 
  marine 
  worms 
  and 
  casts 
  of 
  sea- 
  

   weeds. 
  It 
  sunk 
  very 
  deep, 
  we 
  should 
  find, 
  however, 
  some 
  of 
  the 
  chalk-forming 
  

   protozoa, 
  still 
  living 
  in 
  the 
  bed 
  of 
  the 
  Atlantic, 
  which 
  are 
  so 
  abundant 
  in 
  the 
  

   Old 
  World. 
  

  

  Another 
  cause 
  for 
  scarcity 
  of 
  organic 
  life 
  in 
  these 
  beds 
  is 
  suggested 
  in 
  the 
  

   greater 
  prevalence 
  of 
  volcanic 
  action 
  on 
  the 
  shores 
  of 
  the 
  Pacific 
  than 
  of 
  the 
  

   Atlantic, 
  by 
  which, 
  during 
  periods 
  of 
  rapid 
  subsidence, 
  the 
  water 
  was 
  probably 
  

   heated 
  or 
  poisoned 
  through 
  vast 
  extents 
  of 
  the 
  ocean. 
  

  

  I 
  have 
  before 
  stated 
  the 
  evidence 
  to 
  show 
  that, 
  during 
  the 
  miocene 
  and 
  plio- 
  

   cene 
  epochs, 
  California 
  was 
  constantly 
  rising 
  above 
  the 
  sea, 
  and 
  we 
  have 
  evi- 
  

   dence 
  also 
  that 
  this 
  rise 
  was 
  commenced 
  in 
  the 
  cretaceous, 
  from 
  the 
  existence 
  

   of 
  coal-beds 
  referred 
  to 
  that 
  age, 
  in 
  the 
  strata 
  adjoining 
  to 
  which 
  we 
  find 
  fossil 
  

   laud-plants, 
  and 
  trunks 
  of 
  trees. 
  But 
  as 
  the 
  cretaceous 
  elsewhere 
  was 
  an 
  age 
  

   of 
  almost 
  general 
  subsidence 
  of 
  the 
  continents, 
  we 
  might 
  rather 
  suppose 
  that 
  

   after 
  the 
  burying 
  of 
  these 
  coal-beds 
  beneath 
  strata 
  of 
  marine 
  formation, 
  the 
  

   land 
  would 
  rise 
  still 
  more 
  extensively 
  than 
  before, 
  and, 
  as 
  in 
  Europe, 
  we 
  would 
  

   have 
  a 
  grand 
  terrestrial 
  eocene 
  fauna, 
  with 
  comparatively 
  narrow 
  deposits 
  of 
  

   marine 
  fossils 
  along 
  its 
  shores. 
  We 
  find, 
  however, 
  that 
  the 
  old' 
  geological 
  

   divisions 
  of 
  time, 
  founded 
  on 
  studies 
  in 
  Europe, 
  are 
  still 
  less 
  applicable 
  here 
  than 
  

   in 
  the 
  Atlantic 
  States, 
  and 
  there 
  is 
  reason 
  to 
  suspect 
  that 
  while 
  the 
  great 
  and 
  

   complete 
  change 
  from 
  the 
  cretaceous 
  to 
  Ae 
  tertiary 
  ages 
  was 
  occurring 
  th3re, 
  

   this 
  Coast 
  was 
  undergoing 
  a 
  very 
  gradual 
  transmutation, 
  with 
  only 
  partial 
  ex- 
  

   tinction 
  of 
  the 
  cretaceous 
  life, 
  or 
  an 
  evolution 
  of 
  the 
  tertiary 
  therefrom. 
  

  

  The 
  evidence 
  is 
  so 
  far 
  derived 
  from 
  only 
  a 
  few 
  marine 
  fossils 
  which 
  have 
  been 
  

   referred 
  by 
  diflferent 
  authors 
  to 
  the 
  cretaceous, 
  the 
  eocene, 
  and 
  the 
  miocene. 
  

   Pboc. 
  Cai, 
  Ac.\i>. 
  Sci., 
  Vol. 
  V.— 
  27. 
  December, 
  1874. 
  

  

  