﻿Report 
  of 
  the 
  State 
  Geologist. 
  361 
  

  

  There 
  are 
  two 
  small 
  subtriangular 
  bones, 
  undoubtedly 
  the 
  

   intermaxillaries 
  of 
  the 
  upper 
  jaw, 
  lying 
  embedded 
  in 
  the 
  rock 
  at 
  

   the 
  points 
  marked 
  a 
  and 
  b. 
  One 
  of 
  these 
  (\) 
  it 
  has 
  been 
  pos- 
  

   sible 
  to 
  remove 
  ; 
  the 
  other 
  is 
  complicated 
  with 
  the 
  extremity 
  of 
  

   the 
  mandible 
  {man. 
  1) 
  in 
  such 
  a 
  way 
  as 
  to 
  render 
  its 
  removal 
  

   without 
  damage 
  to 
  the 
  latter 
  impossible. 
  I 
  have 
  represented 
  

   these 
  two 
  bones 
  at 
  the 
  front 
  of 
  the 
  diagram, 
  in 
  the 
  relative 
  

   position 
  which 
  they 
  bear 
  on 
  the 
  specimen. 
  Each 
  is 
  concave 
  on 
  

   the 
  inner 
  surface, 
  convex 
  externally, 
  and 
  bore 
  a 
  somewhat 
  

   extended 
  inner 
  apophysis, 
  which 
  in 
  each 
  case 
  has 
  been 
  broken 
  

   off. 
  There 
  is 
  no 
  evidence 
  of 
  denticles 
  or 
  a 
  tubercled 
  surface 
  ; 
  

   the 
  lower 
  edge 
  is, 
  however, 
  rather 
  sharp 
  and 
  would 
  have 
  served 
  

   a 
  cutting 
  purpose. 
  

  

  Dr. 
  Newberry 
  restored 
  the 
  cranial 
  structure 
  in 
  Dinicthys 
  

   intermedins* 
  and 
  there 
  are 
  many 
  points 
  of 
  similarity 
  in 
  the 
  com- 
  

   position 
  of 
  the 
  cranial 
  plates 
  as 
  given 
  by 
  him 
  and 
  that 
  seen 
  in 
  our 
  

   specimen. 
  While 
  the 
  characteristic 
  triangular 
  form 
  of 
  the 
  cranium 
  

   of 
  Dinicthys 
  is 
  here 
  absent 
  and 
  there 
  is 
  a 
  palpably 
  closer 
  agree- 
  

   ment 
  in 
  the 
  cranial 
  structure 
  of 
  C.f 
  halmodeus 
  and 
  C. 
  decipiens 
  y 
  

   still 
  the 
  former 
  with 
  its 
  Dinicthys 
  mandibles 
  and 
  intermaxillaries 
  

   serves 
  to 
  demonstrate 
  very 
  forcibly 
  the 
  closeness 
  of 
  the 
  relations 
  

   existing 
  between 
  Coccosteus 
  and 
  Dinicthys. 
  

  

  This 
  description 
  may 
  be 
  closed 
  with 
  the 
  account 
  of 
  a 
  second 
  

   specimen 
  from 
  the 
  same 
  horizon, 
  in 
  regard 
  to 
  the 
  nature 
  of 
  which 
  

   I 
  have 
  felt 
  there 
  is 
  room 
  for 
  doubt. 
  In 
  its 
  general 
  external 
  

   aspect 
  and 
  outline 
  it 
  is 
  quite 
  similar 
  to 
  the 
  median 
  and 
  anterior 
  

   portion 
  of 
  the 
  cranium. 
  Upon 
  removing 
  a 
  portion 
  of 
  the 
  plate 
  

   on 
  the 
  right 
  it 
  appears 
  that 
  there 
  are 
  two 
  well-defined 
  and 
  sym- 
  

   metrical 
  lines 
  on 
  the 
  inferior 
  cast, 
  which 
  have 
  the 
  same 
  relative 
  

   position 
  and 
  extent 
  as 
  the 
  median 
  longitudinal 
  pair 
  of 
  sensory 
  

   canals 
  of 
  the 
  cranium. 
  That 
  these, 
  however, 
  are 
  not 
  such 
  canals, 
  

   but 
  sutures, 
  I 
  think 
  is 
  satisfactorily 
  shown, 
  not 
  only 
  by 
  the 
  sharp 
  

   impressions 
  they 
  have 
  left 
  in 
  the 
  inner 
  matrix, 
  but 
  also 
  by 
  the 
  

   fact 
  that 
  in 
  breaking 
  off 
  a 
  portion 
  of 
  the 
  plate 
  the 
  fracture 
  stops 
  

   sharply 
  at 
  this 
  line 
  and 
  leaves 
  a 
  clean 
  vertical 
  surface 
  transsecting 
  

   the 
  entire 
  thickness 
  of 
  the 
  bone. 
  This 
  pair 
  of 
  sutures 
  divides 
  

   the 
  shield 
  into 
  three 
  plates, 
  one 
  sublanceolate 
  median, 
  two 
  broad 
  

   undivided 
  lateral 
  plates. 
  The 
  median 
  plate 
  bears 
  on 
  its 
  inner 
  

  

  * 
  Op. 
  cit., 
  pi. 
  lii., 
  fig. 
  2. 
  

  

  46 
  

  

  