﻿The 
  Succession 
  of 
  the 
  Fossil 
  Faunas 
  in 
  the 
  

   Section 
  of 
  the 
  Livonia 
  Salt 
  Shaft. 
  

  

  Although 
  the 
  detailed 
  section, 
  which 
  has 
  been 
  given 
  by 
  

   Mr. 
  Luther 
  in 
  the 
  preceding 
  pages, 
  affords 
  a 
  fund 
  of 
  information 
  

   as 
  to 
  the 
  succession 
  of 
  the 
  faunas, 
  it 
  has 
  seemed 
  desirable, 
  even 
  

   at 
  the 
  risk 
  of 
  partial 
  repetition, 
  to 
  bring 
  together 
  under 
  one 
  head 
  

   all 
  the 
  knowledge 
  obtained 
  which 
  bears 
  upon 
  the 
  appearance, 
  

   predominance 
  and 
  disappearance 
  of 
  organic 
  types. 
  From 
  the 
  

   outset 
  of 
  the 
  work 
  it 
  was 
  the 
  purpose 
  to 
  record 
  the 
  exact 
  horizon 
  

   of 
  every 
  recognizable" 
  species 
  obtained, 
  and 
  this 
  has 
  been 
  done 
  in 
  

   every 
  instance 
  in 
  which 
  there 
  has 
  been 
  no 
  doubt 
  as 
  to 
  such 
  points. 
  

   As 
  elsewhere 
  explained, 
  each 
  specimen 
  received 
  the 
  mark 
  of 
  its 
  

   horizon 
  as 
  it 
  was 
  taken 
  out, 
  and 
  the 
  fossils 
  were 
  collected, 
  not 
  

   alone 
  with 
  the 
  purpose 
  of 
  securing 
  excellence 
  in 
  preservation, 
  

   but 
  of 
  obtaining, 
  as 
  far 
  as 
  circumstances 
  permitted, 
  a 
  full 
  repre- 
  

   sentation 
  of 
  the 
  organic 
  life 
  in 
  the 
  rocks 
  excavated. 
  The 
  careful 
  

   method 
  of 
  blasting 
  in 
  benches 
  and 
  the 
  precise 
  measurements 
  

   made 
  by 
  Mr. 
  Luther 
  have 
  reduced 
  the 
  error 
  in 
  these 
  determina- 
  

   tions 
  to 
  its 
  lowest 
  terms. 
  Care 
  has 
  been 
  taken 
  to 
  make 
  this 
  

   record 
  of 
  faunas 
  as 
  complete 
  as 
  possible, 
  the 
  more 
  so 
  in 
  view 
  of 
  

   the 
  fact 
  that 
  no 
  such 
  section 
  affording 
  an 
  uninterrupted 
  sequence 
  

   through 
  so 
  many 
  feet 
  of 
  palaeozoic 
  strata, 
  with 
  such 
  unrestricted 
  

   opportunity 
  to 
  study 
  the 
  fossils 
  of 
  these 
  strata, 
  has 
  ever 
  before 
  

   been 
  afforded. 
  

  

  It 
  is 
  a 
  most 
  regrettable 
  circumstance 
  that 
  the 
  first 
  384 
  feet 
  of 
  

   this 
  remarkable 
  section 
  was 
  lost 
  from 
  influences 
  beyond 
  control, 
  

   and 
  this 
  has 
  lost 
  to 
  us, 
  for 
  the 
  present 
  at 
  least, 
  a 
  complete 
  section 
  

   of 
  the 
  Genesee 
  shales 
  and 
  the 
  upper 
  and 
  most 
  highly 
  f 
  ossilif 
  erous 
  

   beds 
  in 
  the 
  Hamilton 
  group. 
  

  

  Mr. 
  Luther 
  has 
  succeeded 
  in 
  restoring 
  the 
  geological 
  section 
  

   by 
  careful 
  study 
  of 
  outcrops 
  in 
  the 
  vicinity 
  of 
  the 
  shaft, 
  but 
  we 
  

   have 
  no 
  more 
  precise 
  knowledge 
  of 
  the 
  missing 
  faunas 
  than 
  such 
  

  

  