﻿Plate 
  15 
  

  

  Page 
  

  

  Figs. 
  1—6. 
  Laterocavea 
  dutempleana 
  D'Orbigny, 
  1S53 
  85 
  

  

  1,2. 
  A 
  bifurcated 
  frond, 
  natural 
  size 
  and 
  X12, 
  showing 
  

   the 
  broad 
  celluliferous 
  frontal 
  face. 
  

   3. 
  Celluliferous 
  face, 
  >(25. 
  

   4, 
  5. 
  Lateral 
  noncelluliferous 
  face, 
  X12 
  and 
  X25. 
  

  

  6. 
  Tangential 
  thin 
  section, 
  X25, 
  showing 
  the 
  arrange- 
  

  

  ment 
  of 
  the 
  mesopores 
  around 
  the 
  peristomes. 
  

   Lower 
  Cretaceous 
  (Aptian) 
  : 
  Faringdon, 
  England. 
  

   Figs. 
  7-10. 
  Zonopora 
  arborea 
  Koch 
  and 
  Dunker, 
  1837 
  90 
  

  

  7. 
  Zoarial 
  fragments, 
  natural 
  size. 
  

  

  8, 
  9. 
  Portion 
  of 
  a 
  specimen, 
  X12 
  and 
  X25, 
  exhibiting 
  no 
  

   zones 
  of 
  mesopores. 
  

  

  10. 
  Specimen, 
  X12, 
  showing 
  a 
  false 
  ovicell. 
  

  

  Lower 
  Cretaceous 
  (Valangian) 
  : 
  Sainte-Croix, 
  Switzer- 
  

   land. 
  

   Figs. 
  11-14. 
  Sparsicavea 
  irregularis 
  D'Orbigny, 
  1853 
  91 
  

  

  11. 
  Specimens, 
  natural 
  size. 
  

  

  12. 
  A 
  reticulated 
  specimen, 
  X12. 
  

  

  L3. 
  Specimen 
  showing 
  the 
  large 
  areas 
  of 
  mesopores, 
  X12. 
  

  

  14. 
  Same 
  specimen, 
  X25. 
  The 
  apertures 
  are 
  rounded 
  

  

  and 
  the 
  mesopores 
  are 
  polygonal. 
  

   Lower 
  Cretaceous 
  (Aptian): 
  Faringdon, 
  England. 
  

   Figs. 
  15-17. 
  Zonopora 
  compressa, 
  new 
  species 
  90 
  

  

  15. 
  Fragments, 
  natural 
  size. 
  

  

  10, 
  17. 
  A 
  bifurcated 
  frond, 
  X12, 
  and 
  portion, 
  X25. 
  

   Lower 
  Cretaceous 
  (Valangian): 
  Sainte-Croix, 
  

   Switzerland. 
  

   108 
  

  

  