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  PROCEEDINGS 
  OF 
  THE 
  CALIFORNIA 
  

  

  Conrad, 
  the 
  Nestor 
  of 
  American 
  palaeontoloo;i3ts, 
  over 
  twenty 
  years 
  ago, 
  de- 
  

   scribed 
  as 
  unmistakably 
  eocene, 
  a 
  group 
  of 
  fossils, 
  now 
  known 
  as 
  the 
  Tejon 
  

   group, 
  among 
  which 
  he 
  thought 
  was 
  the 
  Cardila 
  planicosta, 
  " 
  that 
  finger-post 
  

   of 
  the 
  eocene, 
  both 
  in 
  Europe 
  and 
  America." 
  Mr. 
  Gabb, 
  finding 
  from 
  better 
  

   specimens 
  that 
  this 
  shell 
  diffcTed 
  from 
  Cardita 
  plairicosta, 
  described 
  it 
  as 
  

   new, 
  and 
  referred 
  the 
  Tejitn 
  gronp 
  to 
  the 
  cretaceous, 
  finding 
  in 
  it 
  a 
  very 
  few 
  

   species 
  which 
  he 
  considered 
  identical 
  with 
  the 
  lower 
  beds, 
  proved 
  to 
  be 
  creta- 
  

   ceous 
  by 
  the 
  presence 
  of 
  numerous 
  ammonites. 
  He 
  also 
  stated, 
  in 
  an 
  article 
  in 
  

   our 
  Proceedings, 
  published 
  November, 
  1865, 
  that 
  "a 
  solitary 
  ammonite, 
  repre- 
  

   sented 
  by 
  half 
  a 
  dozen 
  specimens, 
  has 
  been 
  found 
  by 
  myself 
  in 
  plare, 
  even 
  to 
  

   the 
  very 
  top 
  of 
  the 
  formation." 
  This 
  slender 
  evidence 
  (which 
  might 
  be 
  rejected 
  

   after 
  finding 
  a 
  carboniferous 
  fossil 
  in 
  a 
  pliocene 
  deposit) 
  is 
  all 
  the 
  proof 
  we 
  have 
  

   of 
  the 
  TL'jun 
  beds 
  being 
  cretaceous 
  ; 
  and 
  that 
  it 
  is 
  quite 
  arbitrary 
  is 
  shown 
  by 
  

   the 
  other 
  fossils 
  foan 
  1 
  with 
  it 
  being 
  nearly 
  all 
  different 
  from 
  the 
  lower 
  ones, 
  less 
  

   than 
  one-tenth 
  of 
  the 
  cretaceous 
  shells 
  being 
  common 
  to 
  both 
  according 
  to 
  

   Gabb, 
  of 
  which 
  several 
  may 
  be 
  distinct. 
  On 
  the 
  other 
  hand, 
  many 
  of 
  the 
  Tejon 
  

   group 
  are 
  :5Curcely 
  distinguishable 
  from 
  tertiary 
  and 
  living 
  forms. 
  One,Aturia 
  

   Mathewsordi, 
  is 
  so 
  near 
  the 
  eocene 
  A. 
  zigzag, 
  as 
  to 
  have 
  been 
  taken 
  for 
  it, 
  no 
  

   other 
  cretaceous 
  Aturia 
  being 
  known. 
  

  

  I 
  may 
  add 
  that 
  the 
  ammonite 
  (J. 
  jiigaHs, 
  Gabb) 
  was 
  found 
  by 
  me 
  in 
  a 
  stratum 
  

   just 
  beneath 
  the 
  Mt. 
  Diablo 
  coal, 
  and 
  apparently 
  on 
  the 
  same 
  level 
  as 
  those 
  from 
  

   Clayton 
  and 
  " 
  Curry's," 
  found 
  by 
  Gabb, 
  so 
  that 
  its 
  existence 
  above 
  the 
  coal, 
  or 
  

   in 
  the 
  Ttjon 
  group 
  itself, 
  is 
  perhaps 
  accidental. 
  But, 
  to 
  pass 
  by 
  this 
  doubtful 
  

   era, 
  we 
  have 
  still 
  later 
  strata, 
  referred 
  to 
  the 
  eocene 
  by 
  Conrad, 
  near 
  the 
  mouth 
  

   of 
  the 
  Columbia, 
  where 
  we 
  would 
  expect 
  the 
  first 
  tertiary 
  to 
  rise 
  near 
  the 
  sur- 
  

   face, 
  and 
  this 
  time 
  the 
  eocene 
  Aturia 
  zigzag 
  again 
  appears, 
  though 
  with 
  a 
  

   different 
  group 
  of 
  shells. 
  Mr. 
  Gabb, 
  while 
  admitting 
  that 
  this 
  time 
  it 
  is 
  the 
  

   true 
  zigzag, 
  is 
  so 
  opposed 
  to 
  recognizing 
  any 
  eocene 
  here, 
  that 
  he 
  calls 
  the 
  

   formation 
  miocene 
  ! 
  The 
  general 
  character 
  of 
  these 
  fossils, 
  of 
  which 
  there 
  are 
  

   several 
  in 
  the 
  Academy's 
  Museum, 
  shows, 
  however, 
  that 
  they 
  are 
  of 
  a 
  more 
  

   tropical 
  group 
  than 
  any 
  of 
  our 
  miocene 
  species, 
  the 
  Aturia 
  itself 
  being 
  very 
  simi- 
  

   lar 
  to 
  the 
  Nautili 
  now 
  living 
  in 
  the 
  tropics. 
  Though 
  perhaps 
  mixed 
  with 
  miocene 
  

   species 
  among 
  the 
  broken 
  rocks 
  so 
  numerous 
  on 
  the 
  lower 
  Columbia 
  shores, 
  it 
  

   is 
  m0 
  5t 
  probable 
  that 
  true 
  eocene 
  strata 
  exist 
  there, 
  and, 
  as 
  shown 
  by 
  the 
  Acad- 
  

   emy's 
  specimens 
  extend 
  south 
  nearly 
  to 
  California, 
  where 
  later 
  strata 
  cover 
  them. 
  

   From 
  all 
  we 
  yet 
  know, 
  we 
  may 
  assume 
  that 
  the 
  gap 
  between 
  the 
  cretaceous 
  and 
  

   tertiary, 
  so 
  marked 
  on 
  the 
  Atlantic 
  shores, 
  was 
  bridged 
  over 
  in 
  part 
  by 
  the 
  ex- 
  

   istence 
  here 
  of 
  the 
  •' 
  Tejon 
  Group," 
  continuing 
  cretaceous 
  forms 
  of 
  mollusca 
  

   down 
  so 
  as 
  to 
  be 
  contemporaneous 
  with 
  the 
  eocene 
  epoch 
  there, 
  or 
  the 
  earlier 
  

   part 
  of 
  it, 
  just 
  as 
  we 
  find 
  the 
  flora 
  and 
  fauna 
  of 
  Australia 
  resembling 
  forms 
  

   fossil 
  in 
  the 
  eocene 
  formation 
  of 
  Europe, 
  but 
  continued 
  to 
  the 
  present 
  epoch. 
  

   After, 
  perhaps, 
  a 
  short 
  geological 
  period 
  of 
  convulsions 
  and 
  death, 
  we 
  find 
  the 
  

   eocene 
  mollusca 
  appearii:g 
  in 
  Oregon, 
  just 
  preceding 
  the 
  miocene, 
  nearly 
  like 
  

   those 
  of 
  the 
  Atlantic 
  basin. 
  

  

  Though 
  I 
  cannot 
  speak 
  positively 
  on 
  the 
  subject, 
  my 
  impression 
  is 
  that 
  the 
  

  

  