﻿150 
  PALEONTOLOGY 
  OF 
  ILLINOl 
  

  

  Geological 
  position 
  and 
  locality: 
  Warsaw 
  limestone; 
  Jersey 
  county, 
  

   Illinois. 
  

  

  DELTOMS 
  0( 
  ( 
  ITiF.NTAI.lS? 
  (Leidy, 
  Bp.) 
  

  

  PI. 
  IX. 
  Fir. 
  »-l«. 
  

   Compare 
  DeUodui 
  ulU, 
  (Coohllodoc 
  Lm.PWL 
  

  

  „:,,.<. 
  Ni.v.r.,Ki^ 
  a..<l 
  Woi.nn.N. 
  lsfifi, 
  1! 
  f. 
  PL 
  IX. 
  I 
  

  

  j/ 
  The 
  collectioifrom 
  the 
  Warsaw 
  and 
  St. 
  Louis 
  formations 
  contain 
  

   rare 
  examples 
  of 
  the 
  teeth 
  of 
  both 
  the 
  mandibular 
  posterior 
  and 
  

   median 
  forms 
  and 
  of 
  the 
  maxillary 
  posterior 
  form 
  of 
  a 
  spi 
  I 
  

   closely 
  allisd 
  to, 
  if 
  indeed 
  it 
  proves 
  not 
  to 
  be 
  identical 
  with, 
  Delto- 
  

   ,/„,■ 
  occidental™, 
  (Leidy 
  sp.) 
  so 
  numerously 
  represented 
  in 
  t! 
  

   kuk 
  limestone. 
  The 
  Warsaw 
  specimens, 
  of 
  which 
  ■ 
  Binglfl 
  example 
  

   of 
  the 
  posterior 
  tooth 
  of 
  the 
  upper 
  and 
  lower 
  jaws 
  respectively 
  

   been 
  obtained, 
  though 
  fragmentary, 
  present 
  so 
  close 
  a 
  resemblance 
  

   to 
  the 
  Keokuk 
  species 
  that 
  were 
  their 
  Btratigrapbical 
  derivation 
  

   known 
  they 
  would 
  without 
  hesitation 
  be 
  relegated 
  thereto. 
  The 
  

   maxillary 
  tooth 
  (Warsaw) 
  does 
  not 
  show 
  quite 
  as 
  angular 
  corona] 
  

   ridge, 
  but 
  in 
  the 
  outline 
  and 
  coronal 
  contour 
  in 
  other 
  respects 
  it 
  is 
  

   most 
  intimate 
  in 
  its 
  relations 
  with 
  that 
  ■ 
  The 
  mandibular 
  

  

  tooth 
  (Jersey 
  county) 
  preserves 
  only 
  part 
  of 
  the 
  middle 
  or 
  elevated 
  

   portion 
  of 
  the 
  tooth, 
  the 
  borders 
  and 
  extremities 
  being 
  mutilated 
  

   showing 
  the 
  genera] 
  characteristics 
  save 
  the 
  Longitudinal 
  rid 
  

   tributable 
  to 
  the 
  Keokuk 
  teeth. 
  In 
  B 
  ize 
  they 
  are 
  a 
  little 
  

   than 
  the 
  prevailing 
  dimensions 
  attained 
  by 
  the 
  teeth 
  of 
  that 
  

   The 
  St. 
  Louis 
  Bpecimens 
  are 
  even 
  more 
  like 
  the 
  Keokuk 
  teeth 
  

   far 
  as 
  ,t 
  is 
  possible 
  to 
  judge 
  from 
  the 
  few 
  examples 
  thus 
  far 
  ob- 
  

   tained. 
  The 
  collection 
  Of 
  Mr. 
  \ 
  an 
  Jhunc 
  contains 
  a 
  fragment 
  of 
  

  

  the 
  mandibular 
  posterior 
  tooth, 
  from 
  Alton, 
  and 
  Prof. 
  Wort! 
  

   obtained 
  from 
  the 
  same 
  horizon 
  in 
  Monro, 
  county, 
  an 
  aln 
  

   though 
  Bomewhai 
  orushed 
  and 
  distorted, 
  examplfl 
  of 
  the 
  oppo 
  

  

  t 
  ,„, 
  tll 
  | 
  m1ii1 
  , 
  the 
  I- 
  ft 
  ramus 
  of 
  the 
  upper 
  jaw, 
  in 
  which 
  the 
  

  

  ,ron*] 
  iv 
  m. 
  The 
  ol 
  

  

  , 
  ,„.,,„.,;, 
  [ 
  S 
  ; 
  ,ho 
  very 
  Bimilar 
  to 
  the 
  Keokuk 
  teeth, 
  I 
  

  

  of 
  little 
  under 
  medium 
  

  

  compared 
  with 
  the 
  Keokuk 
  example 
  

  

  