﻿New 
  or 
  Rare 
  Species 
  of 
  Fossils 
  from 
  the 
  

   Horizons 
  of 
  the 
  Livonia 
  Salt 
  Shaft. 
  

  

  Coccosteus 
  (?) 
  halmodeus, 
  sp. 
  nov. 
  

  

  Plate 
  I, 
  figs. 
  1, 
  2. 
  

  

  From 
  the 
  level 
  of 
  825-828 
  feet 
  in 
  the 
  Shaft 
  in 
  the 
  densely 
  

   bituminous, 
  blocky 
  layers 
  of 
  the 
  Marcellus 
  shales, 
  a 
  number 
  of 
  

   specimens 
  of 
  plaeoderm 
  fishes 
  was 
  obtained, 
  some 
  of 
  them 
  of 
  

   large 
  size, 
  coarsely 
  tubercled, 
  and 
  similar 
  to 
  the 
  plates 
  which 
  

   have 
  been 
  termed 
  Aspidicthys 
  by 
  Newberry 
  and 
  von 
  Koenen. 
  

   Of 
  others, 
  two 
  belong 
  to 
  a 
  fish 
  evidently 
  coccostean 
  in 
  its 
  rela- 
  

   tions, 
  and 
  as 
  one 
  of 
  these 
  is 
  in 
  a 
  quite 
  unusual 
  condition 
  of 
  

   preservation 
  for 
  a 
  fish 
  from 
  the 
  Devonian 
  shales 
  of 
  New 
  York, 
  

   it 
  seems 
  desirable 
  to 
  give 
  some 
  account 
  of 
  it, 
  especially 
  as 
  it 
  is 
  

   believed 
  to 
  present 
  some 
  interesting, 
  if 
  not 
  novel, 
  structural 
  

   features.* 
  

  

  This 
  specimen 
  presents 
  the 
  nearly 
  entire 
  dorsal 
  aspect 
  of 
  the 
  

   cranium, 
  with, 
  at 
  the 
  left, 
  perhaps 
  a 
  portion 
  of 
  the 
  plates 
  of 
  

   the 
  ventral 
  side. 
  All 
  of 
  these 
  plates 
  are 
  in 
  very 
  close 
  articulation, 
  

   although 
  the 
  entire 
  armature 
  has 
  been 
  compressed. 
  About 
  the 
  

   main 
  body 
  of 
  plates 
  lie 
  some 
  scattered 
  fragments 
  near 
  the 
  

   posterior 
  region, 
  and, 
  to 
  the 
  left 
  and 
  above, 
  two 
  denticulated 
  

   mandibles, 
  to 
  which 
  detailed 
  reference 
  will 
  be 
  duly 
  made. 
  

  

  The 
  exposure 
  is 
  a 
  clean 
  dorsal 
  surface, 
  showing 
  with 
  great 
  

   clearness 
  the 
  distribution 
  of 
  the 
  coarse 
  and 
  fine 
  granules 
  upon 
  

   the 
  plates. 
  The 
  sutures 
  of 
  the 
  plates 
  are, 
  however, 
  extremely 
  

   obscure, 
  while 
  the 
  sensory 
  canals 
  are 
  very 
  distinct; 
  in 
  conse- 
  

   quence 
  it 
  has 
  been 
  difficult 
  to 
  determine 
  in 
  all 
  instances 
  whether 
  

   certain 
  of 
  these 
  lines 
  are 
  to 
  be 
  regarded 
  as 
  the 
  one 
  or 
  the 
  other, 
  f 
  

  

  * 
  The 
  writer 
  pretends 
  to 
  no 
  accurate 
  knowledge 
  of 
  piscine 
  osteology. 
  No 
  other 
  attempt 
  is 
  

   here 
  made 
  than 
  to 
  present 
  the 
  structure 
  of 
  this 
  fossil 
  so 
  far 
  as 
  it 
  can 
  be 
  made 
  out 
  satisfactorily, 
  

   and 
  in 
  this 
  form 
  to 
  submit 
  the 
  account 
  to 
  the 
  criticism 
  of 
  those 
  more 
  expert 
  in 
  this 
  department 
  

   of 
  research. 
  

  

  f'The 
  reading 
  of 
  the 
  cranial 
  buckler 
  of 
  Coccosteus 
  in 
  much 
  complicated, 
  by 
  the 
  fact 
  that 
  

   certain 
  superficial 
  grooves 
  belonging 
  to 
  the 
  lateral-line 
  system 
  are 
  very 
  conspicuous 
  and 
  apt 
  to 
  

   be 
  mistaken 
  for 
  sutures, 
  while 
  the 
  true 
  sutures 
  are 
  visible 
  with 
  difficulty 
  and 
  can 
  only 
  be 
  made 
  

   out 
  in 
  exceptionally 
  well-preserved 
  examples." 
  (Traquair, 
  loc. 
  cit., 
  p. 
  4.) 
  

  

  