﻿350 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Apr. 
  27, 
  

  

  Calamites 
  arenaceus 
  and 
  Vlmannia 
  selaginoides. 
  In 
  the 
  laminated 
  

   beds 
  overlying 
  the 
  Fish-bed, 
  and 
  marked 
  E 
  in 
  the 
  section, 
  Acrolepis 
  

   has 
  occurred, 
  as 
  it 
  has 
  also 
  in 
  the 
  upper 
  part 
  of 
  the 
  grey 
  stone 
  

   about 
  the 
  horizon 
  marked 
  F. 
  At 
  or 
  about 
  the 
  level 
  marked 
  G 
  was 
  

   also 
  found 
  the 
  large 
  reed-like 
  Plant. 
  At 
  certain 
  horizons 
  of 
  the 
  

   Dun 
  Stone, 
  marked 
  H 
  and 
  I 
  in 
  the 
  section, 
  examples 
  of 
  Acrolepis, 
  

   Ulmcmnia, 
  and 
  Palceonisciis 
  varians 
  have 
  occurred 
  in 
  the 
  order 
  indi- 
  

   cated 
  in 
  the 
  section. 
  And, 
  lastly, 
  a 
  single 
  badly 
  preserved, 
  though 
  

   determinable, 
  specimen 
  of 
  P. 
  varians 
  in 
  the 
  Main 
  or 
  Honeycombe 
  

   Limestone, 
  at 
  the 
  point 
  marked 
  J 
  — 
  this 
  being 
  the 
  highest 
  horizon 
  at 
  

   which 
  traces 
  of 
  Fish 
  or 
  any 
  other 
  fossils 
  have 
  as 
  yet 
  been 
  met 
  with 
  

   at 
  Fulwell. 
  The 
  space 
  between 
  the 
  highest 
  and 
  lowest 
  points 
  of 
  

   occurrence 
  is 
  about 
  fifty-four 
  feet 
  ; 
  and, 
  according 
  to 
  our 
  present 
  

   knowledge, 
  this 
  represents 
  the 
  vertical 
  range 
  of 
  this 
  small 
  group 
  of 
  

   species. 
  

  

  To 
  take 
  a 
  more 
  comprehensive 
  view 
  of 
  the 
  position 
  of 
  these 
  fish- 
  

   bearing 
  strata 
  in 
  the 
  Permian 
  formation, 
  it 
  may 
  be 
  observed 
  that 
  

   they 
  are 
  situated 
  about 
  150 
  feet 
  from 
  the 
  top 
  of 
  the 
  Upper 
  Limestone. 
  

   In 
  the 
  north 
  of 
  Durham 
  this 
  member 
  is 
  the 
  highest 
  in 
  the 
  series 
  ; 
  

   but 
  in 
  Yorkshire 
  its 
  equivalent 
  subdivision 
  (Brotherton 
  Beds 
  and 
  

   Red 
  Marls 
  and 
  Gypsum) 
  is 
  overlain 
  by 
  some 
  marls 
  and 
  red 
  sand- 
  

   stone 
  of 
  no 
  great 
  thickness, 
  which 
  some 
  geologists 
  refer 
  to 
  the 
  

   Permian 
  formation. 
  Assuming 
  that 
  these 
  latter 
  deposits 
  are 
  thus 
  

   rightly 
  classified, 
  the 
  fish-bearing 
  beds 
  will 
  not 
  be 
  more 
  than 
  200 
  

   feet, 
  probably 
  less, 
  from 
  the 
  Trias. 
  On 
  the 
  other 
  hand, 
  they 
  are 
  

   separated 
  from 
  the 
  Coal-measures 
  by 
  the 
  Middle 
  and 
  Lower 
  Lime- 
  

   stones, 
  Marl-slate, 
  and 
  Lower 
  Bed 
  Sandstone, 
  which 
  represent 
  an 
  

   aggregate 
  thickness 
  of 
  460 
  feet. 
  Previous 
  to 
  their 
  discovery, 
  the 
  

   highest 
  authenticated 
  horizon 
  on 
  record 
  for 
  the 
  occurrence 
  of 
  Fish 
  in 
  

   the 
  Permian 
  series 
  of 
  Durham 
  was 
  the 
  inferior 
  beds 
  of 
  the 
  Lower 
  

   Limestone, 
  which 
  had 
  yielded 
  a 
  single 
  specimen 
  of 
  Platysomus 
  

   striatus, 
  — 
  the 
  Marl-slate, 
  however, 
  being 
  their 
  chief 
  and 
  almost 
  only 
  

   horizon. 
  The 
  discovery 
  of 
  the 
  Fulwell 
  Fish 
  has, 
  therefore, 
  carried 
  

   the 
  Permian 
  Yertebrata 
  from 
  the 
  lower 
  beds 
  of 
  the 
  Durham 
  series 
  

   high 
  into 
  the 
  upper, 
  and 
  near 
  enough 
  to 
  the 
  Trias 
  to 
  give 
  to 
  their 
  

   occurrence, 
  perhaps, 
  more 
  than 
  usual 
  interest. 
  

  

  Descriptions 
  of 
  the 
  Species. 
  

  

  Class 
  PISCES. 
  

  

  Order 
  Ganoidei. 
  

  

  Family 
  1. 
  Satjroidei. 
  

  

  ACROLEPIS, 
  Sp. 
  

  

  A. 
  Sedgwickii, 
  Ag. 
  Kirkby, 
  Annals 
  of 
  Nat. 
  Hist. 
  3 
  ser. 
  vol. 
  ix. 
  

   p. 
  269. 
  

  

  About 
  a 
  dozen, 
  or 
  probably 
  rather 
  more, 
  specimens 
  of 
  an 
  Acrolepis 
  

   have 
  occurred, 
  which 
  may 
  possibly 
  belong 
  to 
  one 
  of 
  the 
  forms 
  of 
  

   this 
  genus 
  already 
  described 
  from 
  Permian 
  rocks. 
  All 
  the 
  specimens, 
  

   with 
  one 
  exception, 
  are 
  fragments. 
  The 
  perfect 
  specimen 
  belongs 
  

  

  