﻿PLATE 
  XXVII. 
  

  

  A3IPHICCELIA 
  LEIDn 
  Hall 
  

  

  'Page 
  171 
  . 
  

   Fig. 
  1. 
  An 
  imperfect 
  left 
  valve. 
  

  

  Fig. 
  2. 
  An 
  imperfect 
  right 
  valve, 
  which 
  presents 
  some 
  difference 
  in 
  the 
  form 
  

  

  and 
  position 
  of 
  the 
  beak 
  ; 
  probably 
  indicating 
  a 
  distinct 
  species. 
  

  

  MODIOLOPSIS 
  PERLATUS 
  Hall. 
  

  

  Page 
  172. 
  

  

  lis;. 
  3. 
  A 
  risrht 
  valve 
  characteristic 
  of 
  the 
  species. 
  

  

  Fig. 
  L 
  Cardinal 
  view 
  of 
  the 
  same, 
  showing 
  the 
  convexity 
  of 
  the 
  valve. 
  

  

  MODIOLOPSIS 
  5UBALATUS 
  Hall. 
  

  

  Page 
  173. 
  

  

  Fig. 
  5. 
  The 
  left 
  valve 
  of 
  a 
  form 
  closely 
  resembling 
  the 
  M: 
  sulxilatus 
  of 
  New 
  

  

  York, 
  but 
  of 
  larger 
  dimensions. 
  

   Fig. 
  6. 
  A 
  right 
  valve, 
  having 
  a 
  proportionally 
  greater 
  length 
  — 
  in 
  this 
  feature 
  

  

  more 
  nearly 
  approaching 
  the 
  Xew 
  York 
  specimens. 
  

  

  - 
  

  

  Pterixea 
  beisa 
  Hall. 
  

  

  Page 
  1*3. 
  

  

  Fig. 
  7. 
  The 
  exterior 
  of 
  a 
  small, 
  imperfect 
  left 
  valve, 
  with 
  weii-preserved 
  sur- 
  

   face 
  characters. 
  

   Fig. 
  8. 
  The 
  interior 
  of 
  a 
  large 
  imperfect 
  left 
  valve. 
  

   Fig. 
  9. 
  An 
  internal 
  cast 
  of 
  a 
  small 
  left 
  valve. 
  

  

  ALYTTLARCA 
  SIGILLA 
  Hall. 
  

   -tage 
  1 
  1 
  -±. 
  

   Fig. 
  10. 
  A 
  small 
  right 
  valve 
  of 
  a 
  specimen 
  of 
  this 
  species. 
  

  

  AMB 
  ONYCHIA 
  ACUTIR05TRA 
  Hall 
  

  

  Page 
  171. 
  

  

  See 
  plate 
  7, 
  fig. 
  12, 
  under 
  description 
  of 
  SageneUa 
  eUgans. 
  

   i 
  

  

  Orthoceras 
  simulator 
  Hall. 
  

  

  Page 
  179. 
  

  

  Fig. 
  11. 
  A 
  figment 
  of 
  the 
  septate 
  portion 
  of 
  a 
  specimen, 
  showing 
  its 
  general 
  

  

  form 
  and 
  character. 
  

   Fig. 
  12. 
  A 
  smaller 
  fragment, 
  similar 
  to 
  the 
  last, 
  but 
  apparently 
  retaining 
  the 
  

  

  exterior 
  shell 
  over 
  a 
  portion 
  of 
  the 
  tube. 
  

  

  Trochoceras 
  Waldsournse 
  Hall. 
  

  

  Page 
  179. 
  

  

  Fig. 
  13. 
  Lateral 
  view 
  of 
  a 
  specimen 
  preserving 
  one 
  volution, 
  and 
  showing 
  the 
  

  

  annulations, 
  but 
  no 
  septa. 
  

   Fig. 
  14. 
  Ventral 
  view 
  of 
  the 
  same, 
  showing 
  the 
  compressed 
  condition 
  of 
  the 
  

  

  specimen, 
  and 
  the 
  sinus 
  in 
  the 
  annulations 
  on 
  the 
  ventral 
  side 
  

   Fig. 
  15. 
  Lateral 
  view 
  of 
  a 
  specimen 
  preserving 
  about 
  the 
  same 
  extent 
  of 
  the 
  

  

  tube, 
  with 
  the 
  annulations 
  less 
  distinct, 
  and 
  showing 
  no 
  septa. 
  

  

  