﻿288 
  E. 
  M. 
  Kindle 
  — 
  Age 
  of 
  the 
  Eurypterids 
  of 
  Kokomo. 
  

  

  ington 
  formations 
  appears 
  to 
  afford 
  no 
  grounds 
  for 
  their 
  corre- 
  

   lation. 
  The 
  presence 
  in 
  the 
  Kokomo 
  fauna, 
  on 
  the 
  other 
  

   hand, 
  of 
  species 
  which 
  are 
  represented 
  by 
  identical 
  or 
  nearly 
  

   allied 
  species 
  in 
  the 
  Salina 
  or 
  Cobleskill 
  indicates 
  that 
  it 
  repre- 
  

   sents 
  either 
  a 
  Salina 
  or 
  Cobleskill 
  horizon. 
  

  

  The 
  eurypterids 
  appear 
  to 
  afford 
  no 
  direct 
  evidence 
  concern- 
  

   ing 
  the 
  age 
  of 
  the 
  beds 
  since 
  none 
  of 
  the 
  Kokomo 
  species 
  have 
  

   been 
  recognized 
  outside 
  the 
  Kokomo 
  district 
  by 
  Clarke 
  and 
  

   Ruedemann. 
  One 
  of 
  the 
  Kokomo 
  species 
  however 
  is 
  closely 
  

   enough 
  allied 
  to 
  Eurypterus 
  lacustris 
  of 
  the 
  Bertie 
  waterlime 
  

   to 
  have 
  lead 
  Professor 
  Claypole* 
  to 
  cite 
  this 
  species 
  from 
  the 
  

   Kokomo 
  limestone. 
  Clarke 
  and 
  Ruedemann 
  recognized 
  in 
  

   Drepanopterus 
  characters 
  which 
  they 
  suppose 
  to 
  be 
  ancestral 
  

   to 
  those 
  of 
  certain 
  New 
  York 
  Salina 
  eurypterids. 
  Phyloge- 
  

   netic 
  evidence 
  will 
  undoubtedly 
  become 
  of 
  increasing 
  value 
  in 
  

   correlation 
  as 
  our 
  knowledge 
  of 
  the 
  history 
  of 
  biologic 
  groups 
  

   increases 
  in 
  completeness. 
  But 
  in 
  the 
  present 
  state 
  of 
  our 
  

   knowledge 
  of 
  the 
  very 
  imperfectly 
  known 
  Eurypterida 
  this 
  

   kind 
  of 
  evidence 
  cannot 
  be 
  given 
  much 
  weight 
  when, 
  as 
  

   already 
  pointed 
  out, 
  it 
  is 
  opposed 
  by 
  direct 
  evidence. 
  The 
  

   absence 
  from 
  the 
  Kokomo 
  eurypterid 
  fauna, 
  according 
  to 
  

   Clarke 
  and 
  Buedemann, 
  of 
  any 
  species 
  common 
  to 
  it 
  and 
  any 
  of 
  

   the 
  well 
  known 
  eurypterid 
  horizons 
  above 
  the 
  Lockport 
  in 
  the 
  

   Silurian 
  of 
  New 
  York, 
  suggests 
  a 
  lack 
  of 
  identity 
  between 
  the 
  

   Kokomo 
  and 
  any 
  one 
  of 
  these 
  horizons. 
  It 
  however 
  affords 
  

   no 
  evidence 
  that 
  the 
  Kokomo 
  fauna 
  does 
  not 
  represent 
  a 
  hori- 
  

   zon 
  intermediate 
  between 
  some 
  two 
  of 
  these. 
  It 
  is 
  a 
  striking 
  

   fact 
  that 
  but 
  one 
  of 
  the 
  twenty-nine 
  species 
  of 
  eurypterids 
  

   recorded 
  from 
  the 
  five 
  Silurian 
  eurypterid 
  horizons 
  above 
  the 
  

   Lockport 
  is 
  known 
  above 
  or 
  below 
  the 
  particular 
  horizon 
  in 
  

   which 
  it 
  was 
  discovered. 
  Hence 
  we 
  cannot 
  reasonably 
  expect 
  

   a 
  distinct 
  but 
  closely 
  related 
  horizon, 
  such 
  as 
  the 
  Kokomo 
  is 
  

   believed 
  to 
  be, 
  to 
  contain 
  species 
  identical 
  with 
  any 
  of 
  the 
  New 
  

   York 
  eurypterid 
  horizons. 
  In 
  the 
  writer's 
  opinion, 
  the 
  

   Kokomo 
  Eurypterid 
  fauna 
  represents 
  a 
  horizon 
  of 
  Salina 
  age 
  

   which 
  is 
  as 
  yet 
  faunally 
  unknown 
  in 
  New 
  York. 
  

   * 
  Am. 
  Geol., 
  vol. 
  vi, 
  p. 
  259, 
  1890. 
  

  

  