﻿PLATE 
  V. 
  

  

  Steeptelasma 
  radicals 
  Hall. 
  

  

  Page 
  106. 
  

  

  Figs. 
  1, 
  2. 
  Dorsal 
  and 
  ventral 
  views 
  of 
  an 
  imperfect 
  specimen, 
  showing 
  the 
  

   spreading 
  root-like 
  base. 
  

  

  Fig. 
  3. 
  Lateral 
  view 
  of 
  a 
  similar 
  specimen. 
  

  

  Fig. 
  4. 
  An 
  enlarged 
  longitudinal 
  section, 
  showing 
  the 
  depth 
  of 
  the 
  cup 
  and 
  the 
  

   character 
  of 
  the 
  lamellse. 
  The 
  continuation 
  of 
  the 
  lower 
  part 
  

   from 
  the 
  horizontal 
  line 
  is 
  incorrectly 
  represented, 
  the 
  lamellae 
  

   becoming 
  obsolete 
  and 
  solid 
  at 
  a 
  short 
  distance 
  below. 
  

  

  Zaphrentis 
  celator 
  Hall. 
  

   . 
  Page 
  107. 
  

   Figs. 
  5, 
  6. 
  Lateral 
  and 
  posterior 
  views 
  of 
  a 
  specimen 
  showing 
  the 
  form 
  of 
  the 
  

   cup. 
  

  

  Streptelasma 
  (Dtjncanella) 
  borealis 
  Nicholson. 
  

  

  Page 
  106. 
  

  

  Fig. 
  7. 
  A 
  fragment 
  of 
  rock 
  showing 
  two 
  individuals 
  of 
  this 
  species. 
  

   Fig. 
  8. 
  An 
  enlargement 
  of 
  one 
  of 
  the 
  above 
  to 
  show 
  the 
  form 
  and 
  character 
  of 
  

   the 
  exterior. 
  

  

  LlCHENALIA 
  CONCENTRIC 
  A 
  Hall. 
  

   Page 
  116. 
  

  

  Fig. 
  9. 
  A 
  small 
  irregularly 
  growing 
  specimen. 
  

  

  Fig. 
  10. 
  Another 
  irregular 
  specimen 
  — 
  the 
  frond 
  being 
  enrolled 
  upon 
  itself. 
  

  

  Fig. 
  11. 
  Section 
  of 
  the 
  specimen 
  fig. 
  10, 
  showing 
  the 
  great 
  increase 
  in 
  length 
  

   of 
  the 
  cells 
  on 
  the 
  enrolled 
  portion. 
  

  

  Fig. 
  12. 
  The 
  celluliferous 
  surface 
  of 
  a 
  large 
  irregular 
  specimen 
  which 
  has 
  en- 
  

   crusted 
  other 
  bodies, 
  and 
  in 
  places 
  shows 
  a 
  tendency 
  to 
  form 
  

   tubular 
  extensions 
  and 
  branches. 
  

  

  Fig. 
  13. 
  An 
  enlargement 
  from 
  the 
  surface 
  of 
  the 
  specimen 
  fig. 
  9, 
  showing 
  the 
  

   form 
  and 
  arrangement 
  of 
  cells. 
  

  

  Fig. 
  14. 
  An 
  enlargement 
  from 
  the 
  surface 
  of 
  fig. 
  12. 
  showing 
  angular 
  (subtri- 
  

   angular) 
  cell-apertures. 
  This 
  character 
  is 
  shown 
  only 
  on 
  a 
  part 
  of 
  

   the 
  surface, 
  the 
  other 
  portions 
  having 
  oval 
  or 
  circular 
  apertures. 
  

  

  Fig. 
  15. 
  Enlargement 
  from 
  a 
  specimen 
  similar 
  to 
  fig. 
  13, 
  but 
  with 
  larger 
  cells. 
  

  

  Fig. 
  16. 
  A 
  portion 
  of 
  a 
  Strophostylus 
  cyclostomus, 
  bearing 
  four 
  young 
  specimens 
  

   of 
  Lichenalia 
  and 
  the 
  base 
  of 
  a 
  Cornulites 
  ; 
  the 
  entire 
  surface 
  of 
  

   the 
  shell 
  below 
  being 
  covered 
  by 
  another 
  Bryozoan 
  (PaUschara) 
  . 
  

  

  Fig. 
  17. 
  A 
  young 
  frond 
  growing 
  upon 
  the 
  surface 
  of 
  Platyostoma 
  Niagarense. 
  

  

  