﻿186 
  1 
  A 
  I. 
  /HOMOLOGY 
  OF 
  ILLINOIS. 
  

  

  Geological 
  {">xiti"ii 
  and 
  localitiet: 
  Upper 
  Burlington 
  fish-bed 
  : 
  Bur- 
  

   lington, 
  Pleasant 
  Grove, 
  Augusta, 
  Bnffington 
  creek, 
  Louisa 
  county, 
  

   (Iowa); 
  Eoney 
  creek, 
  Henderson 
  county, 
  dll.i 
  The 
  mandibular 
  

   median 
  teeth 
  especially 
  alluded 
  to 
  above 
  are 
  amongst 
  the 
  beautiful 
  

   collections 
  from 
  the 
  Buffington 
  creek 
  locality, 
  belonging 
  to 
  Mr. 
  

   Sprii 
  

  

  Sandalodub 
  i.i.vi-snirs. 
  N. 
  and 
  W. 
  

  

  PL 
  XII, 
  Fig. 
  8, 
  9. 
  

  

  dalodus 
  UeoUtimut 
  Nbwbkbbi 
  and 
  Wobthdt, 
  1884 
  DLOeoL 
  Sun., 
  II, 
  r. 
  IM, 
  PL 
  i". 
  

  

  f. 
  6, 
  -. 
  8. 
  

   Sandalod't 
  * 
  Qr 
  audit, 
  Nf.wherkt 
  and 
  WOBTHKH, 
  U>.. 
  II. 
  p 
  l 
  n 
  "'. 
  IM. 
  in. 
  f. 
  '.'. 
  

   idua 
  orandis, 
  Xewhekry 
  ami 
  WoiiTnEx, 
  il>.. 
  II, 
  p. 
  101, 
  IM. 
  IX. 
  f. 
  ?. 
  Ba. 
  

   • 
  -. 
  N'EwiicniiY 
  and 
  WOBT 
  en. 
  it... 
  II. 
  i'. 
  PI. 
  PL 
  VIII. 
  f. 
  . 
  

   Paammodu* 
  ? 
  temi-cylindricu*, 
  Newberry 
  and 
  WoMHSH, 
  lb., 
  II. 
  p. 
  W, 
  PL 
  XI. 
  f. 
  4. 
  4a. 
  

   rmiodut 
  '- 
  rhomboideva, 
  Nvwbkbbi 
  and 
  Wouthen, 
  lb.. 
  II. 
  p. 
  UO, 
  PL 
  XI, 
  f. 
  

  

  Mandibular 
  median 
  (?i 
  teeth 
  attaining 
  large 
  Bize, 
  triangular 
  in 
  

   outline, 
  strongly 
  arched 
  longitudinally 
  with 
  strong 
  spiral 
  inrollment 
  

   of 
  outer 
  extremity, 
  lateral 
  borders 
  diverging 
  at 
  an 
  angle 
  of 
  about 
  

   Postero-lateral 
  border 
  making 
  an 
  angle 
  of 
  about 
  80 
  with 
  tin- 
  inner 
  

   margin, 
  very 
  gently 
  curved 
  in 
  its 
  course, 
  corona] 
  enamel 
  forming 
  a 
  

   narrow 
  fold 
  Btrongly 
  inbeveled 
  to 
  tin- 
  channeled 
  basal 
  portion, 
  which 
  

   is 
  rounded 
  below 
  into 
  the 
  inferior 
  surface 
  of 
  the 
  tooth: 
  ant 
  

   Lateral 
  border 
  considerably 
  shorter 
  and 
  slightly 
  concave 
  in 
  its 
  

   course, 
  thick 
  articular 
  edge 
  not 
  shown; 
  inner 
  margin 
  very 
  gently 
  

   and 
  regularly 
  arched 
  between 
  the 
  subacute 
  anterior 
  and 
  post 
  

   angles, 
  inbeveled 
  below. 
  

  

  Coronal 
  region 
  presenting 
  a 
  uniform 
  plane 
  Burface 
  transvei 
  

   with 
  a 
  Blight 
  convexity 
  near 
  to 
  and 
  parallel 
  with 
  tin 
  postero-lateral 
  

   border, 
  Interrupted 
  toward 
  inner 
  margin 
  by 
  irregularly 
  dis] 
  

  

  transverse 
  undulations, 
  or 
  lines 
  of 
  growth, 
  and 
  faint 
  longitudinal 
  

   1 
  i 
  1 
  1. 
  s, 
  Rometimes 
  appearing 
  as 
  narrow 
  impressed 
  sulci. 
  Surface 
  

   punctation 
  minute 
  and 
  crowded, 
  along 
  the 
  inner 
  margin 
  com 
  

  

  ith 
  the 
  dense 
  enamel 
  layer. 
  The 
  punctate 
  structure 
  h< 
  ars 
  

  

  men! 
  with 
  that 
  observed 
  in 
  the 
  large 
  posterior 
  fori: 
  

   Sandalodtu 
  lavit$imu. 
  A 
  Lai 
  tooth 
  m 
  the 
  inner 
  

  

  margin 
  •'<•» 
  mm.: 
  Length 
  aloi 
  tero-lateral 
  holder 
  to 
  point 
  of 
  in- 
  

  

  rollment, 
  17 
  mm.; 
  ditto, 
  along 
  the 
  antero-lateral 
  border, 
  about 
  

  

  :;u 
  mm. 
  

  

  