﻿179 
  

  

  Fig, 
  1, 
  b, 
  a 
  portion 
  of 
  the 
  poriferous 
  surface 
  enlarged. 
  

  

  Fig. 
  1, 
  c, 
  another 
  fragment, 
  having 
  elevated 
  nodes 
  upon 
  the 
  surface 
  

   of 
  the 
  branches. 
  

  

  Fig. 
  1, 
  d, 
  an 
  enlarged 
  portion 
  of 
  the 
  non-poriferous 
  face. 
  

  

  Fig. 
  1, 
  e, 
  a 
  similar 
  fragment 
  of 
  the 
  non-poriferous 
  face, 
  partially 
  cov- 
  

   ered 
  by 
  an 
  incrusting 
  coral 
  which 
  has 
  the 
  character 
  of 
  Chastetes. 
  

  

  This 
  species 
  occurs 
  in 
  the 
  lower 
  part 
  of 
  the 
  Trenton 
  limestone, 
  near 
  

   Lowville, 
  Lewis 
  county. 
  (State 
  Collection.) 
  

  

  JEGILOPS, 
  (new 
  genus.) 
  

   Inequilateral, 
  valves, 
  somewhat 
  trigonal, 
  rounded 
  on 
  the 
  base, 
  slop- 
  

   ing 
  abruptly 
  from 
  the 
  beaks, 
  which 
  are 
  incurved 
  at 
  the 
  extremity. 
  

  

  ^GILOPS 
  SUBCARINATA, 
  

  

  Plate 
  4, 
  fig. 
  I, 
  a,b. 
  

  

  Trigonal, 
  with 
  the 
  beaks 
  much 
  elevated 
  and 
  incurved 
  ; 
  anterior 
  slope 
  

   short, 
  ending 
  in 
  a 
  slightly 
  rounded 
  extremity, 
  which 
  continues 
  into 
  the 
  

   curve 
  of 
  the 
  rounded 
  base 
  ; 
  posterior 
  slope 
  long 
  and 
  straight 
  ; 
  surface 
  

   marked 
  by 
  a 
  rounded 
  ridge 
  or 
  carina 
  extending 
  from 
  the 
  beak 
  nearly 
  

   to 
  the 
  base, 
  and 
  margined 
  on 
  each 
  side 
  by 
  a 
  corresponding 
  depres- 
  

   sion. 
  

  

  The 
  form 
  of 
  this 
  shell 
  is 
  peculiar 
  and 
  characteristic, 
  the 
  inequal- 
  

   ity 
  of 
  the 
  valves 
  is 
  only 
  apparent 
  or 
  due 
  to 
  pressure. 
  It 
  is 
  clearly 
  the 
  

   type 
  of 
  a 
  genus 
  which 
  has 
  not 
  hitherto 
  been 
  noticed 
  in 
  the 
  lower 
  Siluri- 
  

   an 
  rocks 
  of 
  this 
  country, 
  if 
  in 
  Europe. 
  

  

  This 
  species 
  was 
  found 
  in 
  the 
  Trenton 
  limestone, 
  near, 
  Lowville* 
  

   Lewis 
  county. 
  (State 
  Collection.) 
  

  

  MURCHISONIA 
  SUBFUSIFORMIS. 
  

  

  Plate 
  4, 
  fig. 
  2. 
  

  

  Reference. 
  — 
  Palaeontology 
  of 
  New- 
  York, 
  vol. 
  1, 
  page 
  234, 
  plate 
  39 
  

   fig. 
  2. 
  

  

  The 
  two 
  figures 
  of 
  this 
  fossil 
  referred 
  to, 
  give 
  but 
  a 
  very 
  imperfect 
  

   idea 
  of 
  the 
  species. 
  Nearly 
  all 
  the 
  specimens 
  procured 
  are 
  so 
  mutila- 
  

   ted 
  that 
  the 
  true 
  form 
  is 
  scarcely 
  to 
  be 
  determined. 
  The 
  specimen 
  

   now 
  figured 
  is 
  the 
  most 
  perfect 
  one 
  that 
  has 
  fallen 
  under 
  my 
  observa- 
  

   tion, 
  and 
  will 
  serve 
  to 
  give 
  a 
  better 
  idea 
  of 
  the 
  form 
  and 
  proportions 
  of 
  

   the 
  species, 
  than 
  those 
  heretofore 
  given. 
  It 
  preserves 
  five 
  volutions, 
  

   two 
  volutions 
  of 
  the 
  apex 
  are 
  broken 
  off 
  The 
  specimen 
  is 
  scarcely 
  at 
  

  

  