﻿286 
  E. 
  M. 
  Kindle 
  — 
  Age 
  of 
  the 
  Eurypterids 
  of 
  Kokomo. 
  

  

  the 
  two. 
  It 
  may 
  be 
  observed 
  that 
  one 
  species 
  which 
  Foerste 
  

   finds 
  in 
  the 
  Kokomo 
  fauna, 
  Anopiotheca 
  congregata, 
  was 
  

   described 
  by 
  the 
  writer 
  in 
  connection 
  with 
  the 
  faunas 
  of 
  the 
  

   Noblesville 
  and 
  Huntington 
  dolomites, 
  but 
  in 
  connection 
  with 
  

   the 
  description 
  the 
  statement 
  was 
  made 
  that 
  " 
  the 
  species 
  

   apparently 
  does 
  not 
  belong 
  to 
  the 
  Niagaran 
  fauna 
  and 
  is 
  prob- 
  

   ably 
  a 
  representative 
  of 
  the 
  " 
  Waterlime" 
  fauna.* 
  The 
  occur- 
  

   rence 
  in 
  the 
  Kokomo 
  fauna 
  of 
  a 
  Wilsonia 
  and 
  of 
  Dalmanella 
  

   elegantula 
  might 
  be 
  cited 
  as 
  suggestive 
  of 
  a 
  Lockport 
  horizon. 
  

   The 
  Wilsonia, 
  however, 
  is 
  a 
  distinct 
  species 
  from 
  that 
  found 
  

   in 
  the 
  Noblesville 
  and 
  Huntington 
  and 
  the 
  Dalmanella 
  ele- 
  

   gantula 
  is 
  described 
  as 
  " 
  a 
  small 
  variety 
  " 
  of 
  that 
  species 
  by 
  

   Foerste. 
  The 
  lack 
  of 
  harmony 
  of 
  the 
  remainder 
  of 
  the 
  fauna 
  

   with 
  that 
  of 
  the 
  Lockport 
  appears 
  however 
  to 
  indicate 
  that 
  

   these 
  species 
  represent 
  a 
  heritage 
  from 
  the 
  Lockport. 
  They 
  

   belong, 
  as 
  Hyatt 
  remarks 
  of 
  certain 
  groups 
  of 
  fossils, 
  to 
  " 
  types 
  

   which 
  remain 
  comparatively 
  simple, 
  or 
  do 
  not 
  progress 
  to 
  the 
  

   same 
  degree 
  as 
  others 
  of 
  their 
  own 
  group. 
  "f 
  In 
  association 
  

   with 
  other 
  fossils 
  of 
  distinctly 
  post-Lockport 
  type 
  Dalmanella 
  

   elegantula 
  clearly 
  fills 
  the 
  role 
  of 
  a 
  late 
  survivor 
  of 
  an 
  early 
  

   fauna 
  just 
  as 
  Phacops 
  rana 
  does 
  in 
  the 
  Portage 
  or 
  Phipido- 
  

   mella 
  vanuxemi 
  in 
  the 
  Chemung. 
  . 
  It 
  is 
  a 
  survivor 
  of 
  a 
  fauna 
  

   which 
  has 
  been 
  almost 
  completely 
  replaced 
  by 
  later 
  types. 
  

   The 
  presence 
  in 
  the 
  Kokomo 
  fauna 
  of 
  a 
  Conchidium 
  cannot 
  

   be 
  taken 
  as 
  evidence 
  of 
  its 
  Lockport 
  age. 
  In 
  the 
  Indiana 
  prov- 
  

   ince 
  Oonchidium 
  persists 
  through 
  the 
  Huntington 
  dolomite, 
  

   which 
  is 
  the 
  representative 
  of 
  the 
  Guelph 
  in 
  that 
  region. 
  It 
  is 
  

   true 
  that 
  C 
  oolletti 
  is 
  not 
  allied 
  to 
  the 
  Huntington 
  species, 
  but 
  

   neither 
  is 
  it 
  to 
  any 
  of 
  the 
  Noblesville 
  species 
  of 
  the 
  genus. 
  

   Its 
  specific 
  characteristics 
  are 
  markedly 
  different 
  from 
  those 
  of 
  

   any 
  Nobles 
  ville 
  Conchidium. 
  If 
  comparison 
  of 
  this 
  shell 
  is 
  

   made 
  with 
  C. 
  laqueatum, 
  the 
  form 
  nearest 
  to 
  it 
  in 
  the 
  Nobles- 
  

   ville, 
  it 
  will 
  be 
  seen 
  to 
  have 
  about 
  double 
  the 
  number 
  of 
  plica- 
  

   tions 
  characteristic 
  of 
  that 
  species. 
  The 
  remarkable 
  expansion 
  

   and 
  flattening 
  of 
  the 
  front 
  of 
  the 
  shell 
  sharply 
  differentiates 
  it 
  

   not 
  only 
  from 
  this 
  but 
  from 
  all 
  other 
  species 
  of 
  Conchidium. 
  

   It 
  recalls 
  the 
  extravagant 
  expansion 
  in 
  sub-parallel 
  planes 
  of 
  

   the 
  anterior 
  portion 
  of 
  the 
  shell 
  of 
  Atrypa 
  reticularis 
  which 
  is 
  

   shown 
  by 
  certain 
  varieties 
  in 
  the 
  later 
  stages 
  of 
  its 
  phylogenetic 
  

   history. 
  A 
  primitive 
  pentameroid 
  feature 
  which 
  some 
  of 
  the 
  

   Lockport 
  species 
  of 
  Conchidium 
  exhibit 
  very 
  distinctly 
  in 
  anon- 
  

   plicated 
  umbonal 
  area 
  is 
  conspicuously 
  absent 
  in 
  C. 
  colletti. 
  

   The 
  fine 
  plications 
  and 
  their 
  complete 
  extension 
  over 
  the 
  

   umbones 
  in 
  C. 
  colletti 
  suggest 
  that 
  it 
  belongs 
  to 
  the 
  latest 
  

   surviving 
  type 
  of 
  the 
  genus. 
  

  

  *28th 
  Ann. 
  Kept. 
  Ind. 
  Dept. 
  Geol. 
  & 
  Nat. 
  Res., 
  p. 
  445, 
  1904. 
  

   fPhylogeny 
  of 
  an 
  Acquired 
  Characteristic. 
  Proc. 
  Am. 
  Phil. 
  Soc, 
  vol. 
  

   xxxii, 
  1895. 
  

  

  