﻿180 
  

  

  all 
  compressed, 
  and 
  it 
  shows 
  the 
  peculiar 
  form 
  which 
  clearly 
  distin- 
  

   guishes 
  it 
  from 
  M. 
  bellacincta. 
  

  

  In 
  the 
  shaly 
  portion 
  of 
  the 
  Trenton 
  limestone, 
  near 
  Lowville, 
  Lewis 
  

   county. 
  (State 
  Collection.) 
  

  

  SUBULITES 
  ABBREVIATA, 
  (n. 
  species.) 
  

   Plate 
  3, 
  fig. 
  2, 
  a, 
  b, 
  c. 
  

  

  Short, 
  subfusiform, 
  last 
  volution 
  making 
  nearly 
  the 
  whole 
  bulk 
  of 
  the 
  

   shell 
  ; 
  spire 
  rapidly 
  diminishing 
  ; 
  composed 
  of 
  about 
  three 
  volutions 
  ; 
  

   aperture 
  long, 
  very 
  narrow 
  above 
  ; 
  outer 
  lip 
  straight 
  and 
  parallel 
  to 
  the 
  

   axis 
  of 
  the 
  shell 
  ; 
  margin 
  of 
  the 
  shell 
  opposite 
  the 
  outer 
  lip, 
  and 
  with 
  

   the 
  spire 
  above 
  forming 
  a 
  regular 
  curve 
  from 
  apex 
  to 
  base. 
  

  

  This 
  species 
  possesses 
  the 
  character 
  of 
  the 
  genus 
  as 
  expressed 
  in 
  the 
  

   S. 
  elongata, 
  but 
  it 
  is 
  extremely 
  different 
  from 
  that 
  one 
  in 
  the 
  short 
  spire 
  

   and 
  curved 
  outline 
  of 
  the 
  back 
  of 
  the 
  shell. 
  The 
  specimens 
  are 
  inte- 
  

   resting 
  as 
  presenting 
  a 
  second 
  species 
  of 
  a 
  peculiar 
  genus, 
  and 
  one 
  not 
  

   recognized 
  above 
  the 
  lower 
  silurian 
  period. 
  

  

  The 
  specimens 
  figured 
  were 
  obtained 
  from 
  the 
  semicrystalline 
  lime- 
  

   stone 
  in 
  the 
  higher 
  part 
  of 
  the 
  Trenton 
  limestone, 
  near 
  Watertown, 
  

   Jefferson 
  county. 
  The 
  position 
  and 
  associated 
  fossils 
  are 
  the 
  same 
  as 
  

   in 
  the 
  other 
  species 
  of 
  the 
  genus. 
  (State 
  Collection.) 
  

  

  ONCOCERAS 
  CONSTRICTUM. 
  

   Plate 
  3, 
  fig. 
  3. 
  

  

  Reference. 
  — 
  Page, 
  197, 
  plate 
  41, 
  figs. 
  6 
  and 
  7, 
  Palaeontology 
  of 
  New- 
  

   York, 
  vol. 
  1. 
  

  

  This 
  species 
  was 
  described 
  from 
  fragments 
  and 
  the 
  characters 
  were 
  

   not 
  completely 
  defined. 
  The 
  specimen 
  figured 
  is 
  almost 
  entirely 
  per- 
  

   fect, 
  showing 
  the 
  contracted, 
  nearly 
  circular 
  aperture, 
  and 
  the 
  swelling 
  

   above, 
  which 
  presents 
  a 
  transversely 
  oval 
  section, 
  suddenly 
  tapering 
  

   from 
  thence 
  towards 
  the 
  apex, 
  which 
  is 
  curved 
  from 
  the 
  commencement 
  

   of 
  the 
  contraction 
  ; 
  surface 
  finely 
  striated, 
  with 
  the 
  striae 
  arching 
  up- 
  

   ward 
  along 
  the 
  dorsal 
  line. 
  

  

  This 
  specimen 
  is 
  almost 
  entire, 
  a 
  small 
  portion 
  of 
  the 
  apex 
  having 
  

   been 
  broken 
  off 
  only. 
  It 
  is 
  one 
  of 
  the 
  most 
  remarkable 
  forms 
  of 
  

   cephalopoda 
  in 
  the 
  lower 
  strata. 
  The 
  specimens 
  figured 
  in 
  the 
  first 
  

   volume 
  of 
  the 
  Palaeontology 
  of 
  New- 
  York, 
  are 
  such 
  as 
  are 
  usually 
  

   found, 
  the 
  one 
  now 
  described 
  being 
  the 
  only 
  perfect 
  one 
  known 
  to 
  me. 
  

  

  From 
  the 
  limestone 
  in 
  the 
  neighborhood 
  of 
  Trenton 
  Falls. 
  

  

  