﻿212 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Diaphorostoma 
  niagarense 
  Hall 
  (Fig. 
  141) 
  (1852. 
  Pal 
  N. 
  Y. 
  

   2:287, 
  pi. 
  60) 
  

  

  Distinguishing 
  characters. 
  Globose 
  contour; 
  three 
  to 
  four 
  volu- 
  

   tions; 
  large 
  body 
  whorl, 
  inflated 
  toward 
  the 
  dilated 
  aperture; 
  deeply 
  

   depressed 
  sutures; 
  fine 
  longitudinal 
  and 
  strong 
  transverse 
  striae. 
  

   Not 
  infrequently 
  a 
  sinuosity 
  is 
  indicated 
  by 
  the 
  lines 
  of 
  growth. 
  

  

  Fig. 
  141 
  Diaphorostoma 
  niagarense 
  

  

  Found 
  in 
  the 
  Clinton 
  limestone 
  lenses, 
  and 
  the 
  lower 
  and 
  middle, 
  

   and 
  rarely 
  the 
  upper 
  Rochester 
  shale 
  at 
  Niagara. 
  Also 
  at 
  Lock- 
  

   port 
  and 
  elsewhere 
  (Hall). 
  

  

  Genus 
  pleurotomaria 
  De 
  France 
  

  

  [Ety. 
  : 
  TzAcupd, 
  side; 
  ro/irj, 
  a 
  cut] 
  

  

  (1824. 
  Tableau 
  d. 
  corps 
  organises 
  fossilcs, 
  p. 
  114, 
  ^.nd 
  Diet. 
  sci. 
  

  

  nat. 
  41 
  :38i) 
  

  

  Shell 
  T 
  r 
  o 
  c 
  h 
  u 
  s 
  -shaped, 
  more 
  or 
  less 
  conic, 
  with 
  or 
  without 
  

   umbilicus; 
  volutions 
  angular, 
  flattened, 
  or 
  rounded, 
  their 
  surfaces 
  

   variously 
  ornamented; 
  aperture 
  subquadrate 
  to 
  suborbicular, 
  the 
  

   inner 
  lip 
  thin. 
  The 
  outer 
  lip 
  bears 
  a 
  narrow, 
  deep 
  fissure 
  or 
  sinus, 
  

   which 
  is 
  the 
  unclosed 
  continuation 
  of 
  a 
  revolving 
  band. 
  

  

  Pleurotomaria 
  littorea 
  Hall 
  (Fig. 
  142) 
  (1852. 
  Pal. 
  N. 
  Y. 
  2:12, 
  

  

  pi. 
  4 
  (bis)) 
  

  

  Distinguishing 
  characters. 
  Me- 
  

   dium 
  size; 
  subconical 
  form; 
  

   three 
  to 
  four 
  somewhat 
  ob- 
  

   tusely 
  angular 
  volutions, 
  which 
  

   enlarge 
  rapidly; 
  small 
  umbihcus. 
  

   Found 
  in 
  the 
  upper 
  Medina 
  sandstone 
  at 
  Lockport 
  (Hall). 
  Frag- 
  

   ments 
  in 
  the 
  same 
  rock 
  at 
  Niagara 
  seem 
  to 
  be 
  of 
  this 
  species. 
  

  

  Fig. 
  142 
  Pleurotomaria 
  littorea 
  

  

  